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UBC Theses and Dissertations

Gas absorption on wood pulp cellulose Orr, Ronald Gordon 1970

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i GAS ADSORPTION ON WOOD PULP CELLULOSE by Ronald Gordon Orr B.A.Sc. U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1963 A T h e s i s S u b m i t t e d I n P a r t i a l F u l f i l m e n t Of The Requirements F o r The Degree Of D o c t o r o f P h i l o s o p y In" The . Department Of Chemical E n g i n e e r i n g We accept t h i s t h e s i s as c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d . THE UNIVERSITY OF BRITISH COLUMBIA In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the r equ i r emen t s f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h C o l u m b i a , I ag ree tha t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y pu rposes may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . It i s u n d e r s t o o d tha t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t hou t my w r i t t e n p e r m i s s i o n . Department The U n i v e r s i t y o f B r i t i s h Co lumbia Vancouver 8, Canada ABSTRACT N i t r o g e n , argon and oxygen adsorption isotherms at 78 °K have been determined on samples of solvent exchange d r i e d , f u l l y bleached, k r a f t pulp of 1 western hemlock and D o u g l a s . f i r . The solvent exchange d r y i n g sequence used was water-methanol-n-pentane wi t h the n-pentane removed at room temperature. The pulp samples were i n two groups: one group was beaten to 'various l e v e l s on a P.P.I, m i l l and solvent exchange d r i e d from a water swollen s t a t e ; the second group was a i r d r i e d to d i f f e r e n t moisture contents and then solvent exchange d r i e d . The presence of micropores (Dubinin d e f i n i t i o n ) i n solvent exchange d r i e d c e l l u l o s e has been shown. This f i n d i n g was suggested by the r e s u l t s of H a r r i s , who noted that adsorbents having an average pore radius of l e s s than 18 A i n d i c a t e d an average K e l v i n pore r a d i u s of 18 ft. The f i n d i n g of micropores i n s olvent exchange d r i e d c e l l u l o s e was s u b s t a n t i a t e d by the pore volume d i s t r i b u t i o n which i n d i c a t e d a very l a r g e volume of pores at 18 & r a d i u s , and by the Dubinin p l o t technique f o r the measurement of micropore•volume. Some solvent exchange d r i e d wood pulp samples i n d i c a t e d that up to 70 percent of t h e i r t o t a l pore volume was present as micropores. The presence of micro-pores w i t h the a s s o c i a t e d enhanced adsorption and r e s t r i c t e d a d s o r p t i o n space complicates the a n a l y s i s of isotherms so that the B. E. T. surface area and K e l v i n type pore a n a l y s i s can-not be considered r e l i a b l e . i i i An i n v e s t i g a t i o n i n t o t h e e f f e c t s o f e r r o r s a s s o c i a t e d w i t h a s s u m i n g v a l u e s f o r t h e p h y s i c a l p r o p e r t i e s o f a d s o r b e d m o l e c u l e s l e d t o t h e c o n c l u s i o n t h a t gas a d s o r p t i o n i s u s e f u l f o r i n d i c a t i n g t r e n d s o r f o r use as a p a r a m e t e r f o r c o r r e l a t i o n s o f some p u l p a n d p a p e r p r o p e r t i e s b u t s h o u l d n o t be u s e d t o p o s t u l a t e m o d e l s o f s p e c i f i e d d i m e n s i o n s . The K e l v i n t y p e p o r e a n a l y s i s a n d t h e D u b i n i n p o r e a n a l y s i s h a v e b e e n shown t o be v e r y s e n s i t i v e t o t h e m o d e l a s s u m e d t o d e s c r i b e t h e p h y s i c a l s t r u c t u r e . o f t h e wood p u l p f i b r e . W h i l e gas a d s o r p t i o n t e c h n i q u e s a r e o f d o u b t f u l v a l i d i t y f o r s o l v e n t e x c h a n g e d r i e d p u l p s a m p l e s , t h e B.E.T. a n a l y s i s , was f o u n d t o be q u i t e r e l i a b l e on a i r d r i e d p a p e r s h e e t s . The e x i s t e n c e o f t h e l a r g e v o l u m e o f p o r e s o f a p p r o x -i m a t e l y 18' ft r a d i u s ( c y l i n d r i c a l p o r e m o d e l ) o r 25'ft w a l l s e p a r -a t i o n ( p a r a l l e l s i d e d f i s s u r e m o d e l ) i n s o l v e n t e x c h a n g e d r i e d c e l l u l o s i c m a t e r i a l s w h i c h h a v e b e e n f o u n d by o t h e r w o r k e r s h a s b e e n shown t o be d o u b t f u l . T h i s f i n d i n g i s s u b s t a n t i a t e d by t h e a c c e s s i b i l i t y d a t a o f S t o n e a n d S c a l l a n w h i c h does n o t i n d i c a t e a l a r g e v o l u m e o f p o r e s n e a r t h e most common p o r e s i z e s f o u n d by gas a d s o r p t i o n . P. F. I . m i l l b e a t i n g o f t h e p u l p was f o u n d t o l o w e r t h e s u r f a c e a r e a s l i g h t l y , t o s h i f t t h e p o r e s i z e d i s t r i b u t i o n s l i g h t l y t o l a r g e r p o r e s i z e s a n d t o s u b s t a n t i a l l y l o w e r t h e v o l u m e ' o f p o r e s a t t h e most common p o r e s i z e . The D u b i n i n m i c r o p o r e v o l u m e a n a l y s i s a l s o i n d i c a t e d l o w e r i n g o f m i c r o p o r e v o l u m e w i t h b e a t i n g . T h e s e r e s u l t s l e d t o t h e c o n c l u s i o n t h a t b e a t i n g a f f e c t e d t h e s t r u c t u r e o f t h e p u l p f i b r e e v e n i n s t r u c t u r a l e l e m e n t s o f t h e s m a l l e s t s i z e m e a s u r e d . P a r t i a l d r y i n g o f t h e p u l p h a n d s h e e t s p r i o r t o s o l v e n t e x c h a n g e d r y i n g was f o u n d t o l o w e r t h e s u r f a c e a r e a by n e a r l y two o r d e r s o f m a g n i t u d e a n d t o s h i f t t h e p o r e v o l u m e d i s t r i b u t i o n s t r o n g l y t o t h e s m a l l e r p o r e , s i z e s . The e f f e c t s o f . b e a t i n g a n d d r y i n g were e a s i l y i n t e r -p r e t e d on t h e b a s i s o f t h e S t o n e a n d S c a l l a n p a r a l l e l s i d e d f i s s u r e m o d e l o f t h e s t r u c t u r e o f c e l l u l o s e . C o m p a r i s o n s b e t w e e n i s o t h e r m s h a p e s i n d i c a t e d s o l v e n t e x c h a n g e d r i e d wood p u l p may h a v e a s t r u c t u r e s i m i l a r t o m o n t m o r i l l o n i t e , w h i c h i s known t o h a v e a f l a t p l a t e s t r u c t u r e . The K a g a n e r a n d " t " - p l o t a n a l y t i c a l t e c h n i q u e s w e re a p p l i e d t o t h e s o l v e n t e x c h a n g e d r i e d wood p u l p as a d d i t i o n a l m e t h o d s o f o b t a i n i n g e s t i m a t e s o f t h e s u r f a c e a r e a . The s u r f a c e a r e a s d e t e r m i n e d by t h e s e m e t h o d s w e r e s i g n i f i c a n t l y l a r g e r t h a n t h o s e f o u n d by t h e B. E. T. e q u a t i o n , h o w e v e r , t h e t r e n d s w e r e f o u n d t o be t h e same. H a n d s h e e t s w ere made f r o m t h e p u l p s a m p l e s a n d t h e s e s h e e t s w e r e s u b j e c t e d t o p h y s i c a l t e s t s . The s u r f a c e a r e a s o f t h e s e s h e e t s w e re d e t e r m i n e d a n d t h e b o n d e d a r e a s e s t i m a t e d . The b o n d e d a r e a was f o u n d t o i n c r e a s e w i t h t h e l e v e l o f b e a t i n g . S h e e t d e n s i t y i n c r e a s e d as b o n d e d a r e a i n c r e a s e d j S O d i d t h e b r e a k i n g l e n g t h a n d b u r s t . T e a r f a c t o r d e c r e a s e d as t h e b o n d e d a r e a i n c r e a s e d . VI GAS ADSORPTION ON WOOD PULP CELLULOSE I INTRODUCTION Page A. C e l l u l o s e 1 B. C e l l u l o s e Surface Area ' 4 C. P r e s e n t a t i o n of the Problem 5 I I PREVIOUS WORK A. The E f f e c t of Surface Tension on S t r u c t u r a l Changes i n C e l l u l o s e F i b r e s During Drying ' 7 B. . Stone and S c a l l a n Model f o r the S t r u c t u r e of a Wood Pulp F i b r e 8 C. Sample Requirements f o r Gas Adsorption 9 D. Freeze Drying 9 E. Solvent Exchange Drying 11 F. . Gas Adsorption on C e l l u l o s i c M a t e r i a l s 18 G. I n t e r p r e t a t i o n of Gas Adsorption Results i n Terms of the P a r a l l e l Sided F i s s u r e Model of C e l l u l o s e S t r u c t u r e 48 H . D i s t r i b u t i o n of Water 'in the C e l l Wall 49 I . E f f e c t of Beating on Surface Area of Solvent Exchange Dried Pulps 49 J . The Influence of Composition on P o r o s i t y and Surface Area 51 K. Solute A c c e s s i b i l i t y of C e l l u l o s i c M a t e r i a l s 53 I I I INTER FIBRE BONDING AND MEASUREMENT OF BONDED AREA 59 IV BACKGROUND THEORY A. The B.E.T. Equation and Surface Area 62 B. Most Common Pore Size and Adsorbate Molecule S i z e 66 v i i C. D e t e r m i n i n g Pore S i z e by the K e l v i n Page E q u a t i o n 6 8 D. D u b i n i n Pore S i z e C l a s s i f i c a t i o n s 7 5 1 . Macropores . 7 5 2 . I n t e r m e d i a t e or . T r a n s i t i o n a l Pores 7 6 3 . M i c r o p o r e s 7 8 E. The S p e c i a l Problem o f M i c r o p o r e s 8 0 F. The D u b i n i n Theory o f A d s o r p t i o n on M i c r o p o r o u s S o l i d s 8 3 G. The Kaganer Method f o r D e t e r m i n a t i o n o f the S u r f a c e Area 8 7 H. The Work o f H a r r i s and S i n g 8 9 I . " t " P l o t Method f o r A n a l y s i s o f A d s o r p t i o n Isotherms 92 V APPARATUS j MATERIALS AND EXPERIMENTAL PROCEDURES A. I n t r o d u c t i o n - 9 7 B. D e s c r i p t i o n o f M a t e r i a l s Used 9 7 C. Cont i n u o u s Flow A d s o r p t i o n A p p a r a t u s 9 7 D. The V o l u m e t r i c A p p a r a t u s 1 0 3 E. S o l v e n t E x t r a c t i o n A p paratus 1 0 6 F. B e a t i n g o f P u l p . 1 0 8 G. Paper T e s t i n g 1 0 8 H. E x p e r i m e n t s Performed 1 0 9 VI EXPERIMENTAL RESULTS AND DISCUSSION A. , Isot h e r m s of N i t r o g e n , A r g o n and Oxygen 1 1 1 B. B.E.T. A n a l y s i s o f Isot h e r m s . 1 2 8 C. Pore A n a l y s i s 1 3 8 D. Pore Volume D i s t r i b u t i o n s as C a l c u l a t e d f r om A c c e s s i b i l i t y and Gas A d s o r p t i o n Data 164 V I 1 1 Page E. Dubinin Pore A n a l y s i s 168a F. Kaganer Surface Area Determination 182 G. C e l l u l o s e " t " P l o t s 182 H. Comparison of Surface Areas C a l c u l a t e d by the Various Techniques 192 I. P h y s i c a l T e s t i n g of the Handsheets of the Experimental Pulps 192a VII CONCLUSIONS 201 NOMENCLATURE 20 3 LITERATURE CITED 205 APPENDIX A Experimental Isotherms 214 APPENDIX B Surface Area of Handsheets ( Dynamic Adsorption Apparatus) 218 APPENDIX C 1. Nitrogen Adsorption Data of Hunt,Blaine and Rowen . 219 2. Isotherm Data of Haselton 220 3. Isotherm Data of Merchant 221 4. Isotherm Data of Sommers 223 5. Isotherm Data on Hollow Filament Rayon Supplied by S c a l l a n 224 6. A c c e s s i b i l i t y Data of Stone and S c a l l a n 225 APPENDIX D 1. Pore A n a l y s i s Using Standardized Nitrogen Isotherms 226 2. Pore A n a l y s i s Using Experimental Values of Nitrogen Isotherms 228 3. Pore A n a l y s i s Using Standardized Argon Isotherms 230 k. Pore A n a l y s i s Using Experimental Values of .Argon Isotherms 5. Pore Volumes Expressed as Bulk L i q u i d Volumes 6. Reduced Cumulative Pore Volumes APPENDIX E Grades and S u p p l i e r s of Chemicals Used APPENDIX F 1. Argon Adsorption on Nonporous Adsorbent 2. Nitrogen Standard Isotherms APPENDIX G 1. Corrected Dubinin Data 2. B.E'.T. and Dubinin'(or Kaganer) Data APPENDIX H 1. " t " Plot. Data 2. Comparison of " t " P l o t Values Using the D i f f e r e n t Standard Isotherms APPENDIX I Study on the E f f e c t s of P o s s i b l e E r r o r s i n Volumetric Apparatus APPENDIX J E x t r a p o l a t i o n of Argon Bulk L i q u i d P r o p e r t i e s to 78°K APPENDIX K Comparison of Res u l t s from D u p l i c a t e Samples X LIST OF TABLES Page 1. E f f e c t on S u r f a c e Area o f F i n a l Exchange L i q u i d 14 2. E f f e c t o f I n t e r m e d i a t e S o l v e n t on S u r f a c e A r e a 14 3. Comparison o f S u r f a c e Areas Determined By Water and N i t r o g e n A d s o r p t i o n 20 4. V a r i a t i o n o f S u r f a c e A r e a o f C e l l u l o s e w i t h B e a t e r Treatment 23 5. E f f e c t o f Adsorbed Water on t h e Are a o f Benzene D r i e d , KOH-Extracted C h l o r i t e H o l o c e l l u l o s e 29 6. N i t r o g e n A d s o r p t i o n R e s u l t s on S o l v e n t Exchange D r i e d F i b r e s - B.E.T. Areas and Pore S i z e D i s t r i b u t i o n s 31 7. B. E. T. S u r f a c e Areas o f Samples P r e p a r e d by Sommers 33 8. S u r f a c e Areas and Pore Volumes f o r Is o t h e r m s Determined by Sommers 34 9. B. E. T. Areas and Pore Volumes f o r a V a r i e t y o f C e l l u l o s i c M a t e r i a l s (Stone and S c a l l a n ) 38 10. Porous S t r u c t u r e at V a r i o u s Stages o f D r y i n g a t 25 °C (Stone and S c a l l a n ) 44 11. Porous S t r u c t u r e Developed A f t e r P a r t i a l D r y i n g a t 25 °C and R e s w e l l i n g i n Water 47 12. P r o p e r t i e s o f Macromolecules Used by Stone and S c a l l a n 54 13. Approximate M o l e c u l a r C r o s s - s e c t i o n a l Areas on V a r i o u s M a t e r i a l s 65 14. R e l a t i v e A d s o r p t i o n V a l u e s f o r Benzene At 20 °C on Carbon B l a c k and A c t i v e Carbons 80 15. B. E. T. Monolayer Volumes and Areas o f S o l v e n t Exchange D r i e d Samples 130 16. R a t i o s Showing Dependence o f B.E.T. S u r f a c e A r e a on A d s o r b a t e 131 17. Ranges o f B. E. T. Areas on Beaten Samples 134 18. Dependence o f S u r f a c e A r e a on M o i s t u r e Content 137 19. E f f e c t o f I n i t i a l Data P o i n t on C u m u l a t i v e Pore Volume and C u m u l a t i v e Pore A r e a 141 x i Page 20. Pore Size at Steepest Descent on Desorption Isotherms 146 21. Molecular Volumes of Adsorbates 149 22. Pore Volumes of D i f f e r e n t Sized Pores 156 23. Comparison of Various C a l c u l a t e d Volumes 158 24. Median Pore Size as Determined By Equation 1. l 6 l 25. Comparison Between B. E. T. Surface Areas and Pore Areas 163 26. Area of Pores Above 25-2 ft Wall Separation or 21.2 ft Diameter (Nitrogen Isotherm) 170 27- Intercept Values f o r Corrected and Uncorrected Dubinin P l o t s With Moisture Content as V a r i a b l e 176 28. The E f f e c t of Beating on Corrected Dubinin A n a l y s i s 177 29. Uncorrected Dubinin P l o t I n t e r c e p t s 178 30. Surface Areas as Determined By " t " - P l o t Technique 188 31. " Comparison of Surface Areas C a l c u l a t e d by the Various Techniques 191 32. P h y s i c a l Test Results on Experimental Pulps 193 33- Estimated Bonded Areas of Handsheets 196 x i i LIST OP FIGURES Page 1. Formulae o f C e l l u l o s e 2 2. Model o f Stone and S c a l l a n 10 3. E f f e c t s o f S o l v e n t Exchange D r y i n g From V a r i o u s H y d r o c arbons at D i f f e r e n t Temperatures . 15 4. R e l a t i o n s h i p s Between F i b r e A r e a and R e s i d u a l L i q u i d 16 5. Data o f Hunt, B l a i n e and Rowen: N i t r o g e n A d s o r p t i o n on C o t t o n C e l l u l o s e 22 6. N i t r o g e n I s o t h e r m Data o f H a s e l t o n 26 7. Data o f Merchant Showing E f f e c t o f F i n a l S o l v e n t i n S o l v e n t Exchange D r y i n g on N i t r o g e n I s o t h e r m s 27 8. Data o f Merchant Showing E f f e c t o f D r y i n g and R e s w e l l i n g P r i o r t o S o l v e n t Exchange D r y i n g on N i t r o g e n I s o t h e r m s 28 9. I n f l u e n c e o f B e a t i n g on Pore D i s t r i b u t i o n i n C e l l u l o s e F i b r e s as Determined by Thode, Swanson and Becher 30 10. Sommers I s o t h e r m Data 35 11. Change o f Pore Volume D u r i n g D r y i n g 46 12. The D i s t r i b u t i o n o f Water i n P u l p F i b r e s 50 13. The A c c e s s i b i l i t y Data o f Stone and S c a l l a n 56 14. R e l a t i v e S i z e s o f Most Common Pore S i z e and Adsorbed N i t r o g e n M o l e c u l e s 67 15. E f f e c t o f Changing P h y s i c a l P arameters on Pore Volume D i s t r i b u t i o n ( C y l i n d r i c a l Pore Model) 71 16. E f f e c t o f Changing P h y s i c a l P arameters on Pore Volume D i s t r i b u t i o n ( P a r a l l e l S i d e d F i s s u r e Model) 72 17. E f f e c t o f Model of. T h i c k n e s s o f N i t r o g e n Adsorbed on Pore W a l l s on Pore Volume D i s t r i b u t i o n 74 18. Comparison o f Average Pore S i z e as C a l c u l a t e d By K e l v i n and G u r v i t c h E q u a t i o n s 91 19. Apparent Volume of M i c r o p o r o u s T i t a n i a as F u n c t i o n o f Temperature and A d s o r b a t e 93 x i i i Page 20. Types o f " t " - P l o t s 95 21. B a s i c U n i t s o f Co n t i n u o u s Plow Equipment 98 22. S c h e m a t i c Diagram o f Co n t i n u o u s Flow Equipment 99 23. Sample Tubes f o r Co n t i n u o u s Flow A d s o r p t i o n A p p a r a t u s 101 24. V o l u m e t r i c A d s o r p t i o n A p p a r a t u s 25. S o l v e n t E x t r a c t i o n A p paratus 1 0 ? 26. N i t r o g e n I s o t h e r m s on D u p l i c a t e S o l v e n t Exchange D r i e d Unbeaten P u l p Samples 1 1 2 27. N i t r o g e n I s o t h e r m s on D u p l i c a t e S o l v e n t Exchange D r i e d P u l p Samples Beaten f o r 10 M i n u t e s i n P.. P. I. M i l l 113 28. A r g o n I s o t h e r m s on D u p l i c a t e S o l v e n t Exchange D r i e d Unbeaten P u l p Samples 29. I s o t h e r m s o f N i t r o g e n , Argon and Oxygen at 78 °K on S o l v e n t Exchange D r i e d Unbeaten P u l p 30. I s o t h e r m s o f N i t r o g e n , Argon and Oxygen a t 78 °K on S o l v e n t Exchange D r i e d P u l p Beaten .1 Min. H ° 31. I s o t h e r m s o f N i t r o g e n , Argon and Oxygen a t 78 °K on S o l v e n t Exchange D r i e d P u l p Beaten 3 Min. 1 1 7 32. I s o t h e r m s o f N i t r o g e n and Argon a t 78 °K on S o l v e n t Exchange D r i e d P u l p B e a t e n 5 Min. 1 1 ° 33- I s o t h e r m s o f N i t r o g e n and Argon a t 78 °K on S o l v e n t Exchange D r i e d P u l p Beaten 10 Min. 1 1 9 34. I s o t h e r m s on S o l v e n t Exchange D r i e d Sheets P r e v i o u s l y Vacuum D r i e d 1^0 35- I s o t h e r m s on S o l v e n t Exchange D r i e d Sheets Which C o n t a i n e d 5-3 P e r c e n t M o i s t u r e 121 36. N i t r o g e n I s o t h e r m s a t 78 °K M o i s t u r e Content P r i o r t o S o l v e n t Exchange D r y i n g as Parameter 122 37. N i t r o g e n A d s o r p t i o n on S o l v e n t Exchange D r i e d P u l p C o n t a i n i n g 14.4 % M o i s t u r e 123 38. A d s o r p t i o n Isotherms o f N i t r o g e n , Argon and Oxygen on Vacuum D r i e d Unbeaten P u l p Sheets 124 X I V Page 39. I s o t h e r m s on M o n t m o r i l l o n i t e 126 40. B. E. T. P l o t s f o r N i t r o g e n , Argon and Oxygen on S o l v e n t Exchange D r i e d Unbeaten P u l p 129 41 . The E f f e c t o f B e a t i n g on t h e S o l v e n t Exchange D r i e d B. E. T. S u r f a c e A r e a 133 42. A r e a o f P u l p as a F u n c t i o n o f t h e M o i s t u r e Content P r i o r t o S o l v e n t Exchange D r y i n g 136 43. C u m u l a t i v e Pore Volume D i s t r i b u t i o n s f o r Unbeaten S o l v e n t Exchange D r i e d P u l p U s i n g N i t r o g e n and Argon D e s o r p t i o n I s o t h e r m s 139 44. C u m u l a t i v e Pore A r e a o f Unbeaten S o l v e n t Exchange D r i e d P u l p as Determined By N i t r o g e n and Argon D e s o r p t i o n I s o t h e r m s 140 45. D i f f e r e n t i a l Pore Volume D i s t r i b u t i o n s f o r Unbeaten S o l v e n t Exchange D r i e d P u l p U s i n g N i t r o g e n and Argon D e s o r p t i o n I s o t h e r m s 144 46. Reduced C u m u l a t i v e Pore Volume D i s t r i b u t i o n s f o r A Number o f C e l l u l o s i c M a t e r i a l s 145 47. C u m u l a t i v e Pore Volume E x p r e s s e d As mis o f A d s o r b a t e i n B u l k L i q u i d Form 148 48. C u m u l a t i v e Pore Volume D i s t r i b u t i o n E x p r e s s e d as L i q u i d A d s o r b a t e Vacuum D r i e d - S o l v e n t Exchange D r i e d Sample 150 49. D i f f e r e n t i a l Pore Volume D i s t r i b u t i o n s o f S o l v e n t Exchange Dried-Vacuum D r i e d Handsheets C a l c u l a t e d From N i t r o g e n and Argon Iso t h e r m s 151 50. C u m u l a t i v e Pore Volume D i s t r i b u t i o n w i t h Degree o f B e a t i n g as Parameter C a l c u l a t e d from N i t r o g e n D e s o r p t i o n I s o t h e r m s 153 51. C u m u l a t i v e Pore Volume D i s t r i b u t i o n s o f S o l v e n t Exchange D r i e d P u l p s Beaten V a r y i n g Amounts C a l c u l a t e d from Argon D e s o r p t i o n I s o t h e r m s 154 52. E f f e c t o f Water Content on Reduced C u m u l a t i v e Pore Volume D i s t r i b u t i o n 159 53. Reduced C u m u l a t i v e Pore Volumes as Determined by A c c e s s i b i l i t y and Gas A d s o r p t i o n 165 54. D i f f e r e n t i a l Pore Volume as Determined by A c c e s s i b i l i y and Gas A d s o r p t i o n 166 55. E f f e c t o f Model On C o r r e c t e d D u b i n i n P l o t 171 X V Page 56. S e n s i t i v i t y t o A r e a o f Pores 26 ft W a l l . S e p a r a t i o n Unbeaten Sample 173 57. C o r r e c t e d D u b i n i n P l o t s w i t h M o i s t u r e Content as Parameter 58. D u b i n i n P l o t s o f N i t r o g e n A d s o r p t i o n I s o t h e r m s ( U n c o r r e c t e d ) P e r c e n t M o i s t u r e P r i o r t o S. E. D r y i n g as Parameter 63. " t " - P l o t s w i t h M o i s t u r e Content P r i o r t o S o l v e n t Exchange D r y i n g as Parameter 65. P h y s i c a l P r o p e r t i e s o f Handsheets as a F u n c t i o n o f Time o f B e a t i n g o f P u l p 66. P h y s i c a l P r o p e r t i e s o f Handsheets as a F u n c t i o n o f the B. E. T. S u r f a c e A r e a 67. Dependence o f P h y s i c a l P r o p e r t i e s o f Handsheets on E s t i m a t e d Bonded A r e a 68. Some P h y s i c a l P r o p e r t i e s o f Handsheets as F u n c t i o n o f the I n v e r s e o f the Apparent Bonded Are a 174 175 59. D u b i n i n P l o t s o f N i t r o g e n , Argon and Oxygen A d s o r p t i o n I s o t h e r m s on S o l v e n t Exchange D r i e d „ Unbeaten P u l p ' i a o 60. D u b i n i n P l o t s o f N i t r o g e n A d s o r p t i o n I s o t h e r m s w i t h minutes P. F. I . M i l l B e a t i n g as Parameter 1 ° 1 61,. " t " - P l o t s o f S o l v e n t Exchange D r i e d P u l p u s i n g . D i f f e r e n t " S t a n d a r d " I s o t h e r m s i y 4 62. " t " - P l o t s w i t h Time B e a t e n as Parameter 1 8 6 187 64. " t " - P l o t s o f a V a r i e t y o f C e l l u l o s i c M a t e r i a l s W i t h N i t r o g e n A d s o r p t i o n E x p r e s s e d as Monolayers ^ 194 195 197 198 x v i ACKNOWLEDGMENT Thanks a re extended t o t h e f a c u l t y and s t a f f o f the C h e m i c a l E n g i n e e r i n g Department, U n i v e r s i t y o f B r i t i s h Columbia. The a u t h o r a l s o wishes t o thank t h e F a c u l t y of F o r e s t r y , U n i v e r s i t y o f B r i t i s h C olumbia, B. C. R e s e a r c h , F o r e s t P r o d u c t s L a b o r a t o r y and the B r i t i s h Columbia I n s t i t u t e of Technology f o r the k i n d use o f t h e i r f a c i l i t i e s . Drs. Stone and S c a l l a n o f P u l p and Paper Research I n s t i t u t e o f Canada and Dr. M. R. H a r r i s o f the U n i v e r s i t y o f S a l f o r d a r e t o thanked f o r t h e i r a s s i s t a n c e i n p r o v i d i n g comments and d a t a . A s p e c i a l thank you i s extended t o the a u t h o r ' s p a r e n t s , Mr. and Mrs. Gordon H. O r r , and t h e a u t h o r ' s wife,' C h a r l e e n , f o r t h e i r k i n d a s s i s t a n c e i n p r e p a r a t i o n o f the m a n u s c r i p t . The a u t h o r i s i n d e b t e d t o Dr. R. M. R. B r a n i o n f o r h i s d i r e c t i o n and support and i s g r a t e f u l f o r the f i n a n c i a l a s s i s t a n c e extended by the N a t i o n a l R esearch C o u n c i l . - 1 -I - INTRODUCTION C e l l u l o s e , the main component o f wood and p l a n t f i b r e s , i s the most abundant o r g a n i c raw m a t e r i a l a v a i l a b l e t o man, and i s one o f the few r e s o u r c e s t h a t i s c o n s t a n t l y b e i n g r e p l e n i s h e d . The unique c h e m i c a l and p h y s i c a l n a t u r e o f c e l l u l o s e has l e d t o a wide v a r i e t y o f u s e s . D e s p i t e r e m a r k a b l e advances due t o the i n t e n s e s t u d y o f c e l l u l o s e , t h e r e remains much t o be l e a r n e d about t h i s complex and i n t e r e s t i n g m a t e r i a l . I n most i n d u s t r i a l p r o c e s s i n g , c e l l u l o s i c m a t e r i a l s are t r a n s p o r t e d and t r e a t e d i n an aqueous medium, t h u s the b e h a v i o r o f c e l l u l o s e i n water i s one o f t h e most imp o r t a n t ' p h y s i c a l p r o p e r t i e s t o be s t u d i e d . A - C e l l u l o s e C e l l u l o s e i s a l i n e a r polymer o f D.-glucose a n h y d r i d e u n i t s , each u n i t j o i n e d t o the next by a 1-4g - g l y c o s i d i c l i n k a g e . F i g u r e 1 shows the c h e m i c a l and c o n f i g u r a t i o n a l f o r m u l a e o f the c e l l u l o s e m o l e c u l e (1,2). The degree o f p o l y m e r i z a t i o n , o r D.P., o f c e l l u l o s e v a r i e s w i d e l y w i t h v a l u e s r e p o r t e d o f up t o t e n t h o u s a n d , ( m o l e c u l a r weight o f up t o 1,620,000) ( 1 ) . P a r -t i c u l a r l y i m p o r t a n t t o the p r o p e r t i e s o f c e l l u l o s e are t h e one p r i m a r y and two secondary h y d r o x y l groups p r e s e n t on each mono-m e r i c u n i t . These may p a r t i c i p a t e i n i n t e r - o r i n t r a - m o l e c u l a r hydrogen bonds. Wood p u l p c o n t a i n s c o n s i d e r a b l e q u a n t i t i e s o f h e m i c e l l u l o s e , the amount p r e s e n t v a r y i n g from about 22 p e r c e n t o f t h e h o l o c e l l u l o s e i n an u n b l e a c h e d aspen s e m i c h e m i c a l p u l p t o v i r t u a l l y none i n an a l p h a c e l l u l o s e d i s s o l v i n g p u l p ( 1 ) . _ 2 -CHEMICAL DIAGRAM H H • H H 1 I I I FIGURE - L FORMULAE OF CELLULOSE -3-Whereas c e l l u l o s e i s c o m p r i s e d a l m o s t e n t i r e l y o f a n h y d r o - g l u c o s e u n i t s , t h e h e m i c e l l u l o s e s a l s o c o n t a i n many o t h e r h e x o s e a nd p e n t o s e u n i t s . A . v e r y common m o n o m e r i c u n i t i s a n h y d r o -x y l o s e w i t h anhydro'-mannose f r e q u e n t l y b e i n g p r e s e n t i n a p p r e -c i a b l e a m o u n t s . B e s i d e s t h e s e , t h e r e may be s m a l l .amounts o f t h e a n h y d r o f o r m s o f g l u c o s e , g a l a c t o s e , a r a b i n o s e , a n d r h a m n o s e . H e m i c e l l u l o s e s a l s o i n v a r i a b l y c o n t a i n u r o n i c a c i d u n i t s . The a v e r a g e D. P. o f i s o l a t e d h e m i c e l l u l o s e s i s u s u a l l y a b o u t 150. T h e s e p o l y s a c c h a r i d e s may be c o - p o l y m e r s a n d a r e s o m e t i m e s b r a n c h e d . I n wood p u l p , t h e c e l l u l o s e p o l y m e r c h a i n s a r e u s u a l l y a r r a n g e d p a r a l l e l t o e a c h o t h e r , t h e d e g r e e o f o r d e r v a r y i n g f r o m t h e l e s s o r d e r e d amorphous r e g i o n s t o t h e h i g h l y o r d e r e d c r y s t a l l i n e r e g i o n s w h i c h c a n be d e t e c t e d by x - r a y a n a l y s i s , i n f a r e d s p e c t r a l a n a l y s i s , o r b y - : c h e m i c a l m e t h o d s s u c h as d e u t e r a t i o n o r a c i d h y d r o l y s i s . (3) A l t h o u g h t h e e x a c t s t r u c t u r e o f c e l l u l o s e f i b r e s i s s t i l l n o t a g r e e d u p o n , ' e l e c t r o n m i c r o -s c o p y h a s shown t h a t t h e s e l i n e a r c h a i n s f o r m f i b r i l l a r s t r i n g s w h i c h i n t u r n make up t h e l a r g e r l i g h t m i c r o s c o p i c a l l y v i s i b l e f i b r e (4). Sommers (5) drew a v e r y a p p r o p r i a t e , i f g r o s s l y s i m p l i f i e d , s k e t c h o f t h e c e l l u l o s e f i b r e as b e i n g made up o f r o p e -l i k e f i b r e s composed o f s t r i n g s , a n d t h e s e s t r i n g s . i n t u r n made up o f s m a l l e r s t r i n g s , e t c , down t o t h e p o l y m e r m o l e c u l e i t s e l f . F r e y - W y s s l i n g a n d M u h l e t h a l e r (6) p o s t u l a t e d t h a t f i b r e s a r e made up o f 35 ft t h i c k c r y s t a l l i n e " e l e m e n t a r y f i b r i l s " . T h i s p o s t u l a t e h a s r e c e i v e d some s u p p o r t f r o m t h e x - r a y a n d e l e c t r o n m i c r o s c o p y d a t a o f Heyn (7,8). The s i z e o f t h i s " e l e m e n t a r y f i b r i l " i s s t i l l a s u b j e c t o f much d e b a t e . The s u r f a c e a r e a o f wood p u l p c e l l u l o s e i s o f f u n d a m e n t a l i m p o r t a n c e i n s t u d i e s o f t h e c h e m i c a l r e a c t i v i t y , p h y s i c a l a d -s o r p t i o n , r e t e n t i o n o f d y e s t u f f s a n d s i z i n g m a t e r i a l s , o p t i c a l p r o p e r t i e s a n d many o f t h e o t h e r p h y s i c a l a n d c h e m i c a l p r o p e r t i e s o f t h e p u l p o r t h e p a p e r made- f r o m i t . The s u r f a c e o f wood p u l p may be d i v i d e d i n t o two g e n e r a l r e g i o n s , t h e m i c r o s c o p i c a l l y v i s i b l e e x t e r n a l s u r f a c e a n d t h a t s u r f a c e i n t e r n a l t o t h e c e l l w a l l w h i c h i s p r e s e n t o n l y when t h e f i b r e i s i n a s w o l l e n s t a t e . S i n c e t h e e x t e n t , l o c a t i o n and a v a i l a b i l i t y o f t h e s u r f a c e o f a wood p u l p f i b r e i s a f u n c t i o n o f i t s m i c r o s c o p i c a n d m o l e c u l a r s t r u c t u r e , t h e p o r o u s s t r u c t u r e o f wood p u l p i s an i m p o r t a n t p a r a m e t e r . . . B - C e l l u l o s e . S u r f a c e A r e a The a p p a r e n t s u r f a c e a r e a o f c e l l u l o s e f i b r e s v a r i e s c o n s i d e r a b l y d e p e n d i n g on t h e h i s t o r y a n d s o u r c e o f t h e f i b r e s . F o r e x a m p l e , wood and c o t t o n c e l l u l o s e f i b r e s d r i e d f r o m w a t e r e x h i b i t s p e c i f i c s u r f a c e a r e a s o f 0.4 t o 1.0 sq.m./g. m e a s u r e d m i c r o s c o p i c a l l y ( 9 ) o r by n i t r o g e n a d s o r p t i o n ( 1 0 , 1 1 ) , w h e r e a s s i m i l a r f i b r e s when s o l v e n t e x c h a n g e d r i e d f r o m a w a t e r s w o l l e n s t a t e e x h i b i t n i t r o g e n a d s o r p t i o n s u r f a c e a r e a s o f up t o 200 s q . m. p e r gm. ( 5 , 1 2 , 1 3 ) . The a p p a r e n t s p e c i f i c s u r f a c e a r e a o f c e l l u l o s e f i b r e s - i s a l s o d e p e n d e n t on t h e s o u r c e o f t h e c e l l u l o s e ; t h e more c r y s t a l l i n e c o t t o n f i b r e s b e i n g somewhat l o w e r i n s u r f a c e a r e a t h a n c e l l u l o s e f i b r e s f r o m wood, w h i c h i n t u r n h a v e much l o w e r s u r f a c e a r e a s t h a n t h e c e l l u l o s e f r o m a e r i a l r o o t s o f t h e two p l a n t s p e c i e s v a n d a s u a v i s a n d p h i l o d e n d r o n  g i g a n t u m ( 1 4 ) . -5-The t h e o r e t i c a l maximum s p e c i f i c s u r f a c e a r e a of c e l l u l o s e assuming t h a t each m o l e c u l a r c h a i n i s s e p a r a t e d from i t s n e i g h b o u r s and I s a b l e t o adsorb a monolayer o f a s m a l l d i a -meter a d s o r b a t e may be e s t i m a t e d by one o f two methods:measure-ments on m o l e c u l a r models (the c a t a l i n models were used and i n d i c a t e d a v a l u e o f about 1600 sq.m./gm.)(14)measurement o f t h e a r e a o f s p r e a d i n g o f c e l l u l o s e as a monolayer on wat e r (15), which y i e l d s a s u r f a c e a r e a o f about 1200 sq.m./gm.However i t s h o u l d be kept i n mind t h a t s u r f a c e a r e a on a m o l e c u l a r - l e v e l cannot be p r e c i s e l y d e f i n e d . C - P r e s e n t a t i o n o f the Problem I n i t i a l l y t h i s p r o j e c t was c o n c e i v e d as a st u d y o f the r e l a t i o n s h i p s among t h e bonded a r e a and the p h y s i c a l p r o p e r t i e s of paper. Gas a d s o r p t i o n t e c h n i q u e s were p r o p o s e d as t h e means of m e a s u r i n g the bonded a r e a . These t e c h n i q u e s have been a p p l i e d w i t h c o n s i d e r a b l e s u c c e s s t o s t u d i e s on the s t r u c t u r e o f m a t e r i a l s such as s i l i c a g e l s , porous c a r b o n s , c l a y s and v a r i o u s h eterogeneous c a t a l y t i c m a t e r i a l s . Stone and S c a l l a n (16), H a s e l t o n (13), Merchant (12), Sommers (5). and o t h e r s ' (17-19) have used gas . a d s o r p t i o n t e c h n i q u e s t o st u d y c e l l u l o s i c m a t e r i a l s . " S o l v e n t exchange d r y i n g i s one o f t h e methods t h a t was pr o p o s e d t o y i e l d an e s t i m a t e o f t h e unbonded a r e a o f t h e p u l p f i b r e s p r i o r t o sheet f o r m a t i o n . However, s o l v e n t exchange d r y i n g can r e t a i n much o f the i n t e r n a l a r e a (pore a r e a ) o f the f i b r e . T h i s i n t e r n a l a r e a , w h i l e unable t o c o n t r i b u t e t o i n t e r -f i b r e bonded a r e a , can be t h e s i t e o f i n t r a f i b r e bonds wh i c h w i l l c o n t r i b u t e t o t h e s t r e n g t h o f t h e f i b r e and hence t o the s t r e n g t h o f t h e s h e e t . Thus i t was d e c i d e d t o c o n c e n t r a t e on a -6-s t u d y o f t h e e f f e c t s o f c h a n g e s i n t h e i n t e r n a l s t r u c t u r e s o f t h e wood p u l p when t h e p u l p was s u b j e c t e d t o v a r i o u s t r e a t m e n t s . A l i t e r a t u r e s e a r c h r e v e a l e d a p a p e r by H a r r i s (1^9) i n w h i c h he p r e s e n t e d d a t a on t i t a n i a s a n d a l u m i n a s i n d i c a t i n g t h a t p o r e s w h i c h i n r e a l i t y h a d r a d i i o f l e s s t h a n 18 ft w o u l d a p p e a r as p o r e s o f 18 ft r a d i u s on a d e s o r p t i o n i s o t h e r m . T h i s i m p l i e s t h a t t h e K e l v i n e q u a t i o n i s n o t v a l i d f o r p o r e s o f r a d i i l e s s t h a n 18 ft. Gas a d s o r p t i o n r e s u l t s on s o l v e n t e x c h a n g e d r i e d c e l l u l o s i c m a t e r i a l s (5,12,13,16) i n d i c a t e d t h a t a v e r y l a r g e v o l u m e o f p o r e s i s i n f a c t f o u n d a t 18 ft r a d i u s , . t h e p o r e r a d i u s a t w h i c h H a r r i s i n d i c a t e d many s m a l l e r s i z e d p o r e s w o u l d a l s o a p p e a r . T h e s e r e s u l t s w e r e i n t e r p r e t e d as i m p l y i n g t h a t s o l v e n t e x c h a n g e d r i e d wood p u l p c e l l u l o s e c o n t a i n e d p o r e s o f l e s s t h a n 18 ft r a d i u s ( m i c r o p o r e s by D u b i n i n d e f i n i t i o n , s e c t i o n I V - D - 3) • A b o o k by G r e g g a n d S i n g (20) i n d i c a t e d t h a t when an a d s o r b e n t c o n t a i n s m i c r o p o r e s , t h e u s u a l gas a d s o r p t i o n a n a l y t i c a l t e c h -n i q u e s ( i . e . B.E.T., K e l v i n p o r e a n a l y s i s ) a r e n o t r e l i a b l e . T h u s , as t h e p r e s e n c e o f m i c r o p o r e s i n s o l v e n t e x c h a n g e d r i e d wood p u l p was s u s p e c t e d , t h e r e l i a b i l i t y o f t h e gas a d s o r p t i o n a n a l y t i c a l t e c h n i q u e s . w a s a l s o s u s p e c t f o r s u r f a c e a r e a m e a s u r e m e n t s As a r e s u l t o f t h e s e f i n d i n g s t h e f i n a l o b j e c t i v e s o f t h i s w o r k w e r e : i . t o d e t e r m i n e i f s o l v e n t e x c h a n g e d r i e d wood p u l p c o n t a i n s m i c r o p o r e s a n d i f so a t t e m p t t o . e s t i m a t e t h e i r v o l u m e , i i . to- s t u d y t h e r e l i a b i l i t y o f t h e gas a d s o r p t i o n a n a l y t i c a l t e c h n i q u e s f o r s o l v e n t e x c h a n g e d r i e d wood p u l p a n d a i r d r i e d p u l p s h e e t s . - 6 a -i i i . t o determine i f the large volume of pores of 18 A radius i n solvent exchange dried c e l l u l o s i c materials i s a r e a l volume or an a r t i f a c t of the a n a l y t i c a l technique i v . to determine the changes i n i n t e r n a l structure with beating of the pulp^ and drying of pulp handsheets. v. to determine a model which best suits the changes i n the wood pulp structure and area when i t i s converted into p'aper. - 7 -I I - PREVIOUS WORK A - The E f f e c t Of S u r f a c e T e n s i o n on S t r u c t u r a l Changes I n  C e l l u l o s e F i b r e s D u r i n g D r y i n g U r q u h a r t (21), i n 19295 p o i n t e d o u t t h a t d r y i n g o f c o t t o n c e l l u l o s e f r o m w a t e r i s an i r r e v e r s i b l e p r o c e s s . He f o u n d t h a t t h e amount o f w a t e r a d s o r b e d by a f i b r e o nce d r i e d i s l e s s t h a n t h e w a t e r a d s o r b e d by a n e v e r d r i e d f i b r e . S t o n e (16) h a s shown t h a t t h e p o r o s i t y and s u r f a c e a r e a o f b l e a c h e d s p r u c e s u l p h i t e t r a c h e i d s as m e a s u r e d by s o l v e n t e x c h a n g e -n i t r o g e n a d s o r p t i o n t e c h n i q u e s a r e d e c r e a s e d i r r e v e r s i b l y on d r y i n g . M e r c h a n t (22) f o u n d t h a t d r y i n g a f u l l y b l e a c h e d s u l p h i t e p u l p o v e r p h o s p h o r o u s p e n t o x i d e f o l l o w e d by a r e d i -s p e r s i o n i n w a t e r l o w e r e d t h e s u r f a c e a r e a , as d e t e r m i n e d by s o l v e n t e x c h a n g e and n i t r o g e n a d s o r p t i o n by 60 p e r c e n t . T h o d e , Chase a n d Hu (23) u s i n g a s p e c i f i c dye a d s o r p t i o n t e c h n i q u e a l s o f o u n d an i r r e v e r s i b l e s u r f a c e a r e a d e c r e a s e w i t h d r y i n g . D r y i n g o f p u l p f i b r e s f o l l o w e d by r e d i s p e r s i o n i n w a t e r t o make p a p e r s h e e t s h a s b e e n shown t o r e s u l t i n a p a p e r o f l o w e r t e n s i l e s t r e n g t h by numerous w o r k e r s (16, 23-25). T h i s l o s s o f s t r e n g t h i s g e n e r a l l y a c c e p t e d t o be a r e s u l t o f i r r e v e r s i b l e h y d r o g e n -b o n d i n g b e t w e e n h y d r o x y l - c o n t a i n i n g e l e m e n t s o f t h e f i b r e s w h i c h l o w e r t h e number o f s i t e s a v a i l a b l e f o r i n t e r f i b r e b o n d i n g . C a m p b e l l (26-28) showed how t h e s u r f a c e t e n s i o n f o r c e s o f w a t e r d u r i n g d r y i n g c a n c r e a t e l a r g e p r e s s u r e s o f t h e o r d e r o f 200 a t m o s p h e r e s w h i c h a c t t o b r i n g e l e m e n t s o f t h e c e l l u l o s e f i b r e s i n t o c l o s e c o n t a c t t h u s a l l o w i n g b o n d i n g t o o c c u r . The e x a c t n a t u r e o f t h i s b o n d i n g i s s t i l l d e b a t e d b u t i t i s g e n e r a l l y t h o u g h t t o be i n t e r - a n d i n t r a - f i b r e h y d r o g e n b o n d i n g -8-w i t h some f i b r i l l a r a n d p o s s i b l y some m o l e c u l a r e n t a n g l e m e n t . The c o m p a c t i n g p r e s s u r e i s c a l c u l a t e d by a p p l i c a t i o n o f t h e f u n d a m e n t a l l a w s o f c a p i l l a r i t y (29) t o t h e v a p o u r - l i q u i d i n t e r -f a c e when w a t e r i s h e l d b e t w e e n two p a r a l l e l p l a t e s . T h i s phenomena has b e e n d i s c u s s e d by o t h e r s n o t a b l y Swanson and J o n e s ( 3 0 - 3 D and B a r k a s ( 3 2 ) . L y n e a nd G a l l a y (33) i n t h e i r s t u d i e s on t h e d e v e l o p -ment o f s t r e n g t h o f wet s h e e t s a c h i e v e d , by means o f g l a s s f i b r e webs w i t h a n d w i t h o u t b o n d i n g a g e n t s , a s e p a r a t i o n b e t w e e n t h e s u r f a c e t e n s i o n e f f e c t s a n d i n t e r f i b r e b o n d i n g e f f e c t s . They c o n c l u d e d t h a t t h e g e n e r a l m e c h a n i s m u n d e r l y i n g t h e d e v e l o p m e n t o f s t r e n g t h i n p a p e r webs i s as f o l l o w s . As t h e s o l i d s c o n t e n t o f t h e d r y i n g p u l p s u s p e n s i o n i n c r e a s e s up t o 20-25 p e r c e n t , t h e f i b r e s a r e h e l d t o g e t h e r w i t h i n c r e a s i n g s t r e n g t h e s s e n t i a l l y by s u r f a c e t e n s i o n f o r c e s . T h e s e f o r c e s r e a c h a maximum a t 20-25 p e r c e n t s o l i d s a n d t h e n show a d e c l i n e a t h i g h e r s o l i d s c o n t e n t s . I n t h i s r a n g e o f 20-25 p e r c e n t s o l i d s , i n t e r f i b r e b o n d i n g becomes t h e m a j o r f a c t o r . The s t r e n g t h t h e n i n c r e a s e s c o n t i n u o u s l y t o d r y n e s s . R o b e r t s o n (3*0 came t o e s s e n t i a l l y t h e same c o n c l u s i o n s . 3 - S t o n e a nd S c a l l a n M o d e l f o r t h e S t r u c t u r e o f a Wood P u l p F i b r e S t o n e a nd S c a l l a n (16, 35) h a v e p r o p o s e d a m o d e l f o r t h e s t r u c t u r e o f a wood p u l p f i b r e . E l e c t r o n m i c r o g r a p h s a nd n i t r o g e n a d s o r p t i o n d a t a w e r e i n s t r u m e n t a l i n f o r m i n g t h e i r new i n t e r p r e t a t i o n They p o s t u l a t e d t h a t m i c r o f i b r i l s o f r e c t a n g u l a r c r o s s - s e c t i o n w i t h i n t h e c e l l w a l l a r e l a t e r a l l y a s s o c i a t e d t o f o r m s h e e t s . T h e s e s h e e t s a r e a r r a n g e d c o n c e n t r i c a l l y a r o u n d t h e f i b r e a x i s . T h e s e s h e e t s may a g g r e g a t e i n t o t h i c k e r s h e e t s - 9 -o r l a m e l l a e , t h e a v e r a g e t h i c k n e s s o f w h i c h d e p e n d s upon t h e e x t e n t o f s w e l l i n g o f t h e f i b r e . A f i b r e d r i e d f r o m w a t e r h a s a s i n g l e l a m e l l a , t h e c e l l w a l l , w h e r e a s a c o m p l e t e l y s w o l l e n f i b r e c o n s i s t s o f s e v e r a l h u n d r e d s p a c e d l a m e l l a e . F i g u r e -2 s c h e m a t i c a l l y p o r t r a y s t h e s t r u c t u r e a n d s t r u c t u r a l c h a n g e s o f t h i s m o d e l . C h e m i c a l p u l p i n g i s s e e n a s t h e p r o d u c t i o n o f l a m e l l a e by d i s s o l v i n g away m a t e r i a l w h i c h l i e s b e t w e e n t h e c o a x i a l c e l l u l o s e l a y e r s i n t h e c e l l w a l l . When a s a t u r a t e d h i g h l y s w o l l e n f i b r e d r i e s t h e w a t e r i s r e m o v e d f r o m b e t w e e n l a m e l l a e , c a u s i n g them t o come t o g e t h e r . The m e c h a n i s m o f s w e l l i n g o f a d r i e d f i b r e i s s e e n t o be t h e r e v e r s e o f t h e d r y -i n g m e c h a n i s m . The l o s s o f p o r o s i t y a n d s u r f a c e a r e a on d r y i n g and r e s w e l l i n g a r e a c c o u n t e d f o r by t h e p e r m a n e n t s e a l i n g o f some o f t h e s p a c e s b e t w e e n t h e l a m e l l a e e i t h e r i n p a r t o r com-p l e t e l y by f o r m a t i o n o f i r r e v e r s i b l e h y d r o g e n b o n d s . C - S a m p l e R e q u i r e m e n t s f o r Gas A d s o r p t i o n The g a s a d s o r p t i o n t e c h n i q u e f o r d e t e r m i n i n g t h e s p e c i f i c s u r f a c e a r e a a n d p o r e v o l u m e d i s t r i b u t i o n c a n be an e x t r e m e l y u s e f u l t o o l i f c o r r e c t l y a p p l i e d . U s i n g t h i s t e c h n i q u e one c a n e s t i m a t e t h e s u r f a c e a r e a a v a i l a b l e t o s m a l l g a s m o l e c u l e s and ' e s t i m a t e much o f t h e p o r e s i z e d i s t r i b u t i o n w i t h o u t n o t i c e -a b l y a l t e r i n g t h e s t r u c t u r e . H o w e v e r t h e gas a d s o r p t i o n t e c h -n i q u e d o e s r e q u i r e a d r y a n d h i g h l y o u t g a s s e d s a m p l e . To o b t a i n s u c h a s a m p l e w h i l e r e t a i n i n g t h e s t r u c t u r e o f t h e w e t . w a t e r s w o l l e n c e l l u l o s e s a m p l e h a s b e e n t h e o b j e c t o f much r e s e a r c h . D - F r e e z e D r y i n g Van d e n A k k e r (36) a n d M a r c h e s s a u l t , L o d g e and Mason (37) d r i e d wet mats by f r e e z i n g a n d s u b s e q u e n t s u b l i m a t i o n o f t h e - 1 0 -FIGUBE2. MODEL OF STONE 8 SCALLAN a) DRYING CYCLE — DRYING — S E A T I N G H 2O FULLY SWOLLEN PARTIALLY SWOLLEW UN SWOLLEN b) PULPING OF WOOD DRY WOOD FIBRE FULLY SWOLLEN PULP FI&RE c) POSSIBLE MODES OF FfBRE COLLAPSE \A x < Ui OC m -11-w a t e r ( f r e e z e d r y i n g ) . T h i s m e thod o f e l i m i n a t i n g t h e s u r f a c e t e n s i o n e f f e c t y i e l d s s h e e t s o f v e r y l o w t e n s i l e s t r e n g t h . M e r c h a n t (12) m e a s u r e d t h e s u r f a c e a r e a o f f r e e z e d r i e d p u l p by n i t r o g e n a d s o r p t i o n a n d f o u n d i t t o be s l i g h t l y h i g h e r t h a n t h a t e x p e c t e d f o r w a t e r d r i e d p u l p , h o w e v e r , t h e s u r f a c e a r e a o f t h e - f r e e z e d r i e d s a m p l e was v e r y much a f u n c t i o n o f t h e f r e e z i n g t e m p e r a t u r e and t h e t e m p e r a t u r e a t w h i c h t h e w a t e r was r e m o v e d . M e r c h a n t c o n c l u d e d t h a t h i s r e s u l t s i n d i c a t e t h a t f o r t h e most p a r t w a t e r was u n f r o z e n a t t h e d r y i n g t e m p e r a t u r e s o f -5 and -20 °C and a p p a r e n t l y , t h e w a t e r i s h e l d i n t h e f i b r e s as a s u p e r c o o l e d , l i q u i d . The e x p e r i m e n t a l r e s u l t s o f D e r y a g i n ( 3 8 ) and F r a n k s ( 3 9 ) s u p p o r t t h i s c o n c l u s i o n t o t h e e x t e n t t h a t t h e p r o p e r t i e s o f w a t e r c l o s e t o an e a s i l y w e t t e d s u r f a c e s u c h as c e l l u l o s e d i f f e r c o n s i d e r a b l y f r o m t h o s e o f b u l k w a t e r . P u r i , Sharma a n d L a k h a n p a l (40) m e a s u r e d t h e f r e e z i n g p o i n t d e -p r e s s i o n s o f w a t e r h e l d i n p o r o u s b o d i e s and f o u n d t h a t t h e f r e e z i n g p o i n t d e p r e s s i o n s d e p e n d e d on p o r e s i z e . T h u s , t h e f r e e z e d r y i n g t e c h n i q u e a p p a r e n t l y d o e s n o t c o m p l e t e l y e l i m i n a t e g r o s s s t r u c t u r a l c h a n g e s as c e l l u l o s e f i b r e s a r e d r i e d . E - S o l v e n t E x c h a n g e D r y i n g A n o t h e r commonly u s e d m ethod f o r • o b t a i n i n g a p u l p s a m p l e s u i t a b l e f o r gas a d s o r p t i o n b u t s u p p o s e d l y r e t a i n i n g t h e s t r u c t u r e o f t h e p u l p i n a w a t e r s w o l l e n s t a t e i s s o l v e n t e x -c h a n g e d r y i n g . A s s a f e t a l (41) c l a i m t h a t 75 p e r c e n t o f t h e s u r f a c e was r e t a i n e d i n s o l v e n t e x c h a n g e d r y i n g w i t h e t h a n o l . S o l v e n t e x c h a n g e d r y i n g c o n s i s t s o f r e p l a c i n g • t h e w a t e r by a n o n - p o l a r s o l v e n t o f l o w s u r f a c e t e n s i o n s u c h as b e n z e n e o r n - p e n t a n e . T h i s i s u s u a l l y a c c o m p l i s h e d f i r s t by r e p l a c i n g t h e -12-w a t e r w i t h an a l c o h o l s u c h as m e t h a n o l , t h e n r e p l a c i n g t h e a l c o h o l w i t h t h e f i n a l s o l v e n t . S o m e t i m e s s e v e r a l i n t e r m e d i a t e s o l v e n t s are. u s e d . T h i s t e c h n i q u e o f s o l v e n t e x c h a n g e has b e e n u s e d w i t h c o n s i d e r a b l e s u c c e s s by b i o l o g i s t s i n p r e p a r a t i o n o f t i s s u e m a t e r i a l f o r u s e i n e l e c t r o n m i c r o s c o p y . H o w e v e r , t h e y do n o t u s u a l l y remove t h e f i n a l l i q u i d f r o m t h e t i s s u e s b u t p o l y m e r i z e i t . C o t e ( 4 2 ) h a s a c h i e v e d d r a m a t i c r e s u l t s i n h i s e l e c t r o n m i c r o s c o p e s t u d i e s o f wood c e l l s t r u c t u r e by u s e o f s o l v e n t e x c h a n g e t e c h n i q u e s . F o r z i a t i , B r o w n e l l and Hunt (19) h a v e r e p o r t e d on t h e i r e x p e r i m e n t s t o d e v e l o p a . s o l v e n t e x c h a n g e d r y i n g p r o c e d u r e f o r t h e p r e p a r a t i o n o f s w o l l e n s a m p l e s o f c o t t o n f o r s u r f a c e a r e a m e a s u r e m e n t s . The o b j e c t i v e o f t h e i r w o r k was t o f i n d a m e t h o d t h a t w o u l d g i v e r e p r o d u c i b l e d a t a and a m i n i m a l a l t e r -a t i o n t o t h e e x p a n d e d s t r u c t u r e p r o d u c e d by s w e l l i n g . They f o u n d t h a t p e n t a n e u s e d as t h e f i n a l l i q u i d p r o d u c e d a s a m p l e o f l a r g e r s u r f a c e a r e a t h a n b e n z e n e . They a l s o f o u n d t h a t t h e t e m p e r a t u r e o f t h e s a m p l e d u r i n g r e m o v a l o f t h e f i n a l l i q u i d h a d an e f f e c t on t h e s u r f a c e a r e a w i t h a maximum a r e a o c c u r i n g when t h e p e n t a n e was r e m o v e d by a s t r e a m o f d r y n i t r o g e n a t 0®C. They a l s o s t u d i e d t h e p o s s i b i l i t y t h a t r a p i d r e m o v a l o f w a t e r f r o m c e l l u l o s e d u r i n g t h e s o l v e n t e x c h a n g e p r o c e s s m i g h t r e s u l t i n c o l l a p s e o f t h e e x p a n d e d c e l l u l o s e . T h i s s t u d y was done by e x c h a n g i n g one s a m p l e o v e r a p e r i o d o f s e v e r a l d a y s w i t h g r a d u a l l y i n c r e a s i n g m e t h a n o l c o n c e n t r a t i o n s u n t i l a b s o l u t e m e t h a n o l was r e a c h e d . An i d e n t i c a l s a m p l e was e x c h a n g e d r a p i d l y w i t h a b s o l u t e m e t h a n o l . B o t h s a m p l e s were t h e n t r e a t e d - 1 3 -i d e n t i c a l l y throughout the pentane exchange, d r y i n g and surface area determination. The surface areas of the two samples were found to be the same w i t h i n experimental e r r o r . Merchant. ( 1 2 ) s t u d i e d solvent exchange d r y i n g with respect t o the e f f e c t s of parameters such as temperature of d r y i n g , surface t e n s i o n and p o l a r i t y of f i n a l solvent on.the surface area as determined by n i t r o g e n a d s o r p t i o n . Tables 1 and 2 are taken from h i s work ( 1 2 ) with the a d d i t i o n of the values of the surface t e n s i o n at 2 0 °C, and i n d i c a t e the p o s s i b i l i t y that the solvent exchange d r i e d pulps do not have the same s t r u c t u r e as the water swollen pulps from which they were d e r i v e d . This d i f f e r e n c e i n s t r u c t u r e i s assumed because of the wide range of surface areas found when various solvent exchange d r y i n g parameters are v a r i e d . Table 1 shows the strong r e l a t i o n s h i p between the surface t e n s i o n of the f i n a l solvent of the solvent exchange proceedure and the B. E. T. surface area of the samples. Table 2 shows the intermediate solvent surface t e n s i o n i s not as c r i t i c a l , but that molecular s i z e i s apparently more c r i t i c a l . F igures 3 and 4 which are from Merchant ( 1 2 ) de-monstrate other aspects of whether or not the water swollen s t r u c t u r e i s r e t a i n e d when a pulp sample i s solvent exchange d r i e d . The dependence of surface area on d r y i n g temperature ( f i g u r e 3 ) f o r a given f i n a l solvent was found to be d i r e c t l y p r o p o r t i o n a l to the change i n surface t e n s i o n . However, the e f f e c t of r e s i d u a l l i q u i d s on surface area i s l e s s c l e a r and i s clouded by the d i f f e r e n t d r y i n g temperatures used. Table i : E f f e c t on Surface Area of F i n a l Exchange L i q u i d * * P i n a l Exchange L i q u i d B.E.T. Area Surface Tension sq.m./g. dyne/cm. Benzene 43-0 28.88 Toluene 48.1 28.52 Cyclohexane 88.5 24.99 n-Hexane 108 18.42 n-Pentane 129 16.00 Table 2: E f f e c t of Intermediate Solvent on Surface Area* Intermediate Solvent B.E.T. Area Surface Tension sq.m./g. dyne/cm. Methanol 129 22.55 Ethanol 108 22.32 Ethanol 109 22.32 n-Propanol 103 23-70 * n-Pentane used as f i n a l solvent i n a l l t e s t s . ** Tables 1 and 2 are from Merchant (12). mu*& Z fftt&RAWN FROM MERCHANT 02)) EFFECTS OF SOLVENT EXCHANGE DRYING FROM VARIOUS HYDROCARBONS AT DIFTERENT TEMPERATURES - 1 6 -FIGURE 4. (REDRAWN FROM MERCHANT (12.)) o CO < w cc <• UJ * 00 60-1 4 0 1 2 0 I 0 C -8 0 -6C -4C-zc -A N-PENTANE y N-HEXANE € CYCLOHEXANE O BENZENE • TOLUENE i i 1.0 2 . 0 3.0 RESIDUAL LIQUID % 4.0 RELATIONSHIPS BETWEEN FIBRE AREA AND RESIDUAL LIQUID -17-Sommers (5) proposed that one could e l i m i n a t e many of the problems of solvent exchange d r y i n g by removing the f i n a l s olvent at the c r i t i c a l p o i n t . He used carbon d i o x i d e as h i s f i n a l s o l v e n t . As a r e s u l t of h i s and others' experimental work he concluded:-"Involved i n t h i s process (solvent exchange drying) are the p h y s i c a l and chemical p r o p e r t i e s of the l i q u i d s as w e l l as the c e l l u l o s e , the i n t e r a c t i o n s of these p r o p e r t i e s , and a l s o the e f f e c t of the s t r u c t u r e of the c e l l u l o s e by way of i t s p o r o s i t y and the way i n which the c e l l u l o s i c polymer u n i t s make up the molecular and f i b r i l l a r arrangement. The main i n t e r a c t i o n s a r i s e from secondary valence forces and hydrogen bonding. We s t a r t w i t h c e l l u l o s e i n a water medium where i t i s swollen and f l e x i b l e by v i r t u e of the strong r e l a t i o n s h i p between the water and the c e l l u l o s i c hydroxyl groups mainly as the r e s u l t of hydrogen bonding. Methanol i s then added to t h i s system i n an e f f o r t to replace the water. Removal of some of t h i s water q u i t e l i k e l y leads to a decrease i n the expanded s t r u c t u r e through bonding of c e l l u l o s i c hydroxyls before the s i t e s can be occupied by methanol molecules. The degree of t h i s l o s s i s not known but i t i s expected that i t i s minor with respect to loss e s which occur l a t e r . A l l of the water cannot be replaced because i t i s not p o s s i b l e to ob t a i n a completely water-free a l c o h o l . In a d d i t i o n , experimental evidence shows that some water s t i l l remains which could have been removed by i n c o n v e n i e n t l y long time i n t e r v a l s or some means of mechanical a g i t a t i o n . This water i s b e l i e v e d to remain i n the smallest pore s t r u c t u r e where the forces of a t t r a c t i o n are the strongest and the l i m i t a t i o n s of d i f f u s i o n are most pronounced. The over-a l l e f f e c t of the water removal w i l l l i k e l y cause a small decrease i n the expanded s t r u c t u r e and a small increase i n i t s r i g i d i t y through replacement of part of the water by the lower s w e l l i n g methanol and a l s o by some c e l l u l o s e -t o - c e l l u l o s e hydrogen bonds. S i m i l a r problems occur i n the attempt to replace the methanol by a nonpolar l i q u i d . I t i s expected that the degree of replacement w i l l be lower and the l o s s of the swollen s t r u c t u r e higher than i n the exchange of water by a l c o h o l . This a r i s e s from the attempt to repla c e a s w e l l i n g p o l a r l i q u i d w i t h a nonswelling non-polar one. A lower e f f e c t i v e n e s s i n the exchange i s al s o suggested by the f a c t that small amounts of moisture can prevent complete m i s c i b i l i t y i n the polar-nonpolar system and that considerable unreplaced methanol was found a f t e r attempts to replace i t with benzene. -18-E f f e c t s due to removal of the f i n a l solvent are complicated by the small amounts of unreplaced a l c o h o l and water. Drying from the nonpolar solvent t h e r e f o r e i n v o l v e s the c o n t r i b u t i o n s of the molecular i n t e r -a c t i o n s between the c e l l u l o s e and three d i f f e r e n t l i q u i d s . In macroscopic . terms, each l i q u i d may be looked upon as c o n t r i b u t i n g to the c o l l a p s e of the s t r u c t u r e through i t s f o rces of surface t e n s i o n and i t s e f f e c t on the f l e x i b i l i t y of the s t r u c t u r e . Removal of the f i n a l l i q u i d as a gas above i t s c r i t i c a l p oint e l i m i n a t e s the s u r f a c e - t e n s i o n forces of the f i n a l l i q u i d but only i n those parts of the s t r u c t u r e where i t has been e f f e c t i v e i n replacement of the a l c o h o l . These areas of complete replacement are most l i k e l y i n the l a r g e r pore regions and t h e r e f o r e i t i s here that the CP-method ( i . e . removal of f i n a l solvent above i t s c r i t i c a l p o i n t ) becomes e f f e c t i v e i n p r e s e r v a t i o n • o f the s t r u c t u r e . The unreplaced l i q u i d s conversely show t h e i r e f f e c t mainly i n the smaller pore regions where because of incomplete replacement the surface t e n s i o n of the f i n a l l i q u i d i s of l i t t l e consequence. F - Gas adso r p t i o n on C e l l u l o s i c M a t e r i a l s Sheppard and Newsome (43) used vapour ad s o r p t i o n isotherms i n an attempt to determine the s t r u c t u r e of c e l l u l o s i c m a t e r i a l s as e a r l y as 1929- They adsorbed water onto cotton c e l l u l o s e and various c e l l u l o s e d e r i v a t i v e s . They a l s o c a l -c u l a t e d pore s i z e d i s t r i b u t i o n s using the K e l v i n equation. However, no c o r r e c t i o n s were made f o r the adso r p t i o n of the water molecules onto the w a l l s of the s t r u c t u r e . This work i s remarkable i n i t s conception of the problem because most of the c a l c u l a t i o n a l techniques r e q u i r e d f o r the e x p l o i t a t i o n of t h e i r data had not been published at that time. In 1932, Grace and Maass (44) s t u d i e d the adsorption of water vapour, hydrogen c h l o r i d e , s u l f u r d i o x i d e , ammonia and carbon d i o x i d e on wood and c e l l u l o s e . They d i d not make any estimates of the area or s t r u c t u r e . -19-Emmett and deWltt (10) studied the adsorption of nit r o g e n on samples of paper used as telephone wire i n -s u l a t i o n as part of a study of the a p p l i c a b i l i t y of the B.E.T. equation to a wide range of m a t e r i a l s . They used vacuum d r i e d papers and found the standard "S" type isotherm (type I I isotherm, BDDT c l a s s i f i c a t i o n (page 7 reference 20) y i e l d i n g a l i n e a r B.E.T. p l o t . They concluded from these r e s u l t s , ; that the B.E.T. equation could be a p p l i e d to c e l l u l o s i c m a t e r i a l s . Assaf, Haas and Purves ( 4 l ) noted the wide des-crepancies i n surface areas and a c c e s s i b i l i t i e s of c e l l u l o s e when these f a c t o r s are determined by water adsorption, n i t r o g e n adsorption and by t h a l l a t i o n s with excess t h a l l o u s e t h y l a t e d i s s o l v e d i n normal ethers. Rowen and Bl a i n e (17) measured the adsorption of. nitr o g e n and water vapour on a i r d r i e d p u r i f i e d wool, c o t t o n , s i l k , v i s c o s e rayon, nylon and acetate f i b r e s as w e l l as on t i t a n i u m d i o x i d e . They found that a l l of the f i b r e s had a r e l a t i v e l y low capacity for. adsorption of ni t r o g e n as com-pared with the capacity f o r adsorption of water vapour. Table 3 shows the.magnitude of t h i s d i f f e r e n c e . T a b l e 3 (from 17): Comparison o f S u r f a c e Areas Determined by Water and N i t r o g e n A d s o r p t i o n M a t e r i a l B.E.T, S u r f a c e Areas R a t i o o f Areas H 20 g 20°C N 2 @-195°C H 20 / N 2 sq.m./g. sq.m./g.  Wool 206 0.96 215 V i s c o s e Rayon 204 0.98 208 S i l k 140 0.76 184 C o t t o n 108 0.72 150 A c e t a t e Rayon 58.8 0.38 154 N y l o n 45.0 0.31 145 T i 0 2 7.0 7.90 0.9 They c o n c l u d e d t h i s a p p arent d i s c r e p a n c y may be due t o any o r a l l o f t h e f o l l o w i n g : i . The a d s o r b i n g s i t e s a r e not r e s t r i c t e d t o a s u r f a c e . i i . I f t h e a d s o r b i n g s i t e s a r e r e s t r i c t e d t o a s u r f a c e , t h e r e may be an a d d i t i o n a l i n t e r n a l s u r f a c e s p e c i f i c t o c e r t a i n a d s o r b a t e s as w e l l as an e x t e r n a l s u r f a c e . i i i . The i n t e r n a l s u r f a c e w i t h i n the f i b r o u s s t r u c t u r e e x i s t s o n l y i n the p r e s e n c e o f a s w e l l i n g agent such as w a t e r . i v . The s m a l l e r d i a m e t e r and t h e p o l a r i t y o f t h e wat e r m o l e c u l e e n a b l e i t t o p e n e t r a t e i n t o c a p i l l a r i e s not a c c e s s i b l e t o the n i t r o g e n m o l e c u l e . Because o f the l a c k o f e x p e r i m e n t a l r e s u l t s t h e y d i d not e v a l u a t e the above p r o p o s a l s as t o p o s s i b l e m e r i t s , but p o i n t e d out t h e c o n c l u s i o n o f Stamm and M i l l e t (45) t h a t a l l t h e e s t i m a t e d v a l u e s o f c e l l u l o s e s u r f a c e a r e a i n t h e -21-l i t e r a t u r e ( p r i o r t o 1941) f e l l i>nto two g r o u p s , a l o w g r o u p w h i c h r e p r e s e n t e d " t h e m i c r o s c o p i c a l l y v i s i b l e s u r f a c e " and a h i g h g r o u p w h i c h r e p r e s e n t e d " t h e s u r f a c e o f t h e t r a n s i e n t c a p i l l a r y s t r u c t u r e c r e a t e d w i t h i n t h e c e l l w a l l s by t h e s w e l l -i n g a g e n t s " . H u n t , B l a i n e a n d Rowen (18) i n 1949 r e p o r t e d r e -s u l t s o f e x p e r i m e n t s i n w h i c h t h e y a d s o r b e d n i t r o g e n o n t o • s o l v e n t e x c h a n g e d r i e d c o t t o n l i n t e r s . The s o l v e n t e x c h a n g e was w a t e r t o m e t h a n o l t o b e n z e n e . The i s o t h e r m s o b t a i n e d a r e shown i n f i g u r e 5 and t a b l e I i n a p p e n d i x C. They f o u n d a s u r f a c e a r e a o f 71.3 sq.m/g. f o r c o t t o n l i n t e r s t h a t were s o a k e d i n c o l d 10% s o d i u m h y d r o x i d e , washed and n e u t r a l i z e d , t h e n s o l v e n t e x c h a n g e d r i e d . A c o n t r o l s a m p l e , s o a k e d i n w a t e r i n s t e a d o f a l k a l i h a d an a r e a o f 47.3 s q . m./g. Whe.n t h e a l k a l i t r e a t e d s a m p l e was c o n d i t i o n e d i n w a t e r v a p o u r t o a 3'3% g a i n i n w e i g h t , t h e s u r f a c e a r e a d e c r e a s e d t o 31.6 sq.m./g.; f u r t h e r c o n d i t i o n i n g t o 11.0$ w a t e r d e c r e a s e d t h e s u r f a c e t o 2.1 sq.m/g. The c o l l a p s e o f t h e e x p a n d e d s t r u c t u r e o f t h e s o l v e n t e x c h a n g e d r i e d c e l l u l o s e u p o n w e t t i n g w i t h s m a l l amounts o f w a t e r and d r y i n g l e d Hunt e t a l (18) t o s u g g e s t t h a t t h e e x p a n d e d m a t e r i a l i s i n an u n s t a b l e s t a t e . The s e n - , s i t i v i t y o f s u r f a c e a r e a t o s m a l l amounts o f w a t e r i n d i c a t e d t o t h e s e w o r k e r s t h a t r i g o r o u s e x c l u s i o n o f w a t e r w o u l d have y i e l d e d h i g h e r s u r f a c e area's t h a n t h o s e r e p o r t e d . H u n t , B l a i n e and Rowen (18) a l s o c a l c u l a t e d t h e p o r e s i z e d i s t r i b u t i o n u s i n g t h e method o f W h e e l e r (46) and S h u l l (47). They f o u n d t h e s a m p l e s had a n a r r o w p o r e s i z e d i s T t r i b u t i o n w i t h t h e most common p o r e r a d i u s b e i n g a b o u t 20 A F I G U R E 5 D A T A O F H U N T , B L A I N E 8 R O W E N ( 1 8 ) N I T R O G E N A D S O R P T I O N O N C O T T O N C E L L U L O S E A " A L K A L I - S W O L L E N , S O L V E N T E X C H A N G E D R I E D B - A W I T H 3 . 3 % W A T E R R E G A I N C - A W I T H 1 1 . 0 % W A T E R R E G A I I D - C O N T R O L f o r a l k a l i soaked l i n t e r s and 16 ft f o r water soaked l i n t e r s . In the present work these were r e c a l c u l a t e d by the method of P i e r c e (48) and found to be e s s e n t i a l l y the same at 19 ft. Grotjahn and Hess (49) used argon adsorption at 90°K to study the e f f e c t s of beating on the solvent exchanged B.E.T. surface area. Their r e s u l t s are shown i n Table 4. Table 4: V a r i a t i o n of Surface Area of C e l l u l o s e with Beater Treatment.* 2 Time Beaten Surface Area (m /g) 15 min. 184 30 min. 178 1 hour 200 2 hour 207 3 hour 188 4 hour 193 5 hour 195 These pulps were apparently solvent exchange d r i e d with butanol which was removed under vacuum at 100°C. However, the solvent exchange drying technique i s not elaborated upon i n t h e i r paper Haselton (13,50,51) studied gas adsorption on a spruce wood, spruce pulp, and paper made from t h i s pulp. His work can be considered i n three p a r t s . The f i r s t part (50) was a study of the nature of the low temperature adsorption of n i t r o g e n , n-butane and carbon di o x i d e on f i n e l y ground * Strecker - Muhle Model DKM 00 -24-(40 to 100 mesh) specimens of sprucewood, c h l o r i t e holo-c e l l u l o s e , and KOH - e x t r a c t e d c h l o r i t e h o l o c e l l u l o s e d r i e d from water. The second part (51) was a study of the use of n i t r o g e n adsorption techniques f o r area and s t r u c t u r e s t u d i e s on solvent exchange d r i e d sprucewood and sprucewood pulps. The t h i r d p a r t , which w i l l be discussed i n a l a t e r s e c t i o n of t h i s work, was a study of the bonded and unbonded surface areas of papers as found by various methods i n c l u d i n g gas adsorpti o n . As a r e s u l t of the f i r s t part of h i s study, Haselton (50), concluded that the nature of the adsorption of both n-butane and n i t r o g e n on sprucewood, the c h l o r i t e holo-c e l l u l o s e and the KOH-extracted h o l o c e l l u l o s e i s such that e i t h e r gas could be used f o r area measurements on c e l l u l o s i c m a t e r i a l s . Nitrogen i s the p r e f e r r e d gas to use because i t s s m a l l e r , more s p h e r i c a l molecules have an area which i s more d e f i n i t e l y known, and as i t deviates l e s s from an i d e a l gas, i t i s e a s i e r to work with . Carbon d i o x i d e i s apparently s o l u b l e i n the n o n c e l l u l o s i c c o n s t i t u e n t s of wood.and thus i s not s u i t a b l e f o r surface area s t u d i e s when these m a t e r i a l s are present. Besides t h i s problem, p l o t s of the decrease i n free energy and d i f f e r e n t i a l heat of adsorption versus p a r t i a l pressure and volume of gas adsorbed r e s p e c t i v e l y i n d i c a t e d a moderately strong a t t r a c t i o n such as hydrogen bonding may be o c c u r r i n g f o r carbon d i o x i d e but not f o r n i t r o g e n or n-butane. The B.E.T., Harkins - Jura (52) and F u - B a r t e l l (53) methods of computing surface area from adsorption data were t r i e d and compared. The B.E.T. method was s e l e c t e d as the best method sin c e i t y i e l d e d b e t t e r s t r a i g h t l i n e p l o t s and r e q u i r e d the -25-measurement o f f e w e r p o i n t s on t h e a d s o r p t i o n i s o t h e r m t h a n d i d t h e H a r k i n s - J u r a o r F u - B a r t e l l m e t h o d s . H a s e l t o n (13, 51) i n t h e s e c o n d p a r t o f h i s w o r k , d e t e r m i n e d n i t r o g e n a d s o r p t i o n i s o t h e r m s f o r s o l v e n t e x c h a n g e d r i e d ( w a t e r - m e t h a n o l - b e n z e n e ) s p r u c e w o o d , h o l o c e l l u l o s e a nd KOH e x t r a c t e d c h l o r i t e h o l o c e l l u l o s e . T h e s e i s o t h e r m s a r e g i v e n i n f i g u r e 6 and a r e l i s t e d i n t a b l e 2 o f A p p e n d i x C. From t h e s e d a t a , t h e B. E. T. a r e a s were c a l c u l a t e d a nd p o r e v o l u m e d i s t r i b u t i o n s d e t e r m i n e d f o r t h e c h l o r i t e h o l o c e l l u l o s e and K O H - e x t r a c t e d c h l o r i t e h o l o c e l l u l o s e by t h e m ethod o f : S h u l l ( 4 7 ) . The d i s t r i b u t i o n s were f o u n d t o be e s s e n t i a l l y t h e same, w i t h t h e K O H - e x t r a c t e d m a t e r i a l h a v i n g l a r g e r v a l u e s . The e f f e c t o f a d s o r b e d m o i s t u r e on t h e a c c e s s i b l e B. E. T. a r e a o f b e n z e n e - d r i e d , K O H - e x t r a c t e d c h l o r i t e h o l o c e l l u l o s e was. d e t e r m i n e d and t h e r e s u l t s a r e g i v e n i n T a b l e 5. T h e s e r e s u l t s a r e q u i t e s i m i l a r t o t h o s e r e p o r t e d by H u n t , B l a i n e a nd Rowen (18) f o r c o t t o n c e l l u l o s e . W h i l e M e r c h a n t (12,22) was p r i m a r i l y c o n c e r n e d w i t h a s t u d y o f t h e e f f e c t s o f s o l v e n t e x c h a n g e p a r a m e t e r s on t h e B. E. T. s u r f a c e a r e a , he d i d d e t e r m i n e two s e t s o f i s o t h e r m s w h i c h d r a m a t i c a l l y show t h e e f f e c t o f t h e f i n a l s o l v e n t and t h e e f f e c t o f a i r d r y i n g and r e w e t t i n g a p u l p s a m p l e . T h e s e d a t a a r e shown i n f i g u r e s 7 and 8 and a r e l i s t e d i n t a b l e 3 a p p e n d i x C. M e r c h a n t u s e d t h e method o f P i e r c e (48) t o compute t h e p o r e s i z e d i s t r i b u t i o n s a s a f u n c t i o n o f t h e f i n a l s o l v e n t s o f t h e s o l v e n t e x c h a n g e d r y i n g . He f o u n d e s s e n t i a l l y t h e same-s h a p e d p o r e s i z e d i s t r i b u t i o n c u r v e w i t h t h e m a g n i t u d e o f t h e p o r e v o l u m e i n c r e a s i n g t h r o u g h b e n z e n e - c y c l o h e x a n e - n - p e n t a n e . FIGURE 6, N I T R O G E N I S O T H E R M D A T A O F H A S E L T O N ( 1 3 . ) S O L I D S Y M B O L S - D E S O R P T I O N o j S P R U C E W O O D A 1 C H L O R I T E H O L O C E L L U L O S E • K O H E X T R A C T E D C H L O R I T E - ' " " H O L O C E L L U L O S E 0.2 0.4 P / R 0.6 _ _ i Q8 -27-Q l 1 I I 1 L _ 0 0.2 0.4 0.6 0.8 1.0 P/P. - 2 8 -I I I I i I I 0 02. 0 . 4 0 . 6 0 . 8 \X> P/P9 -29-Table 5*: E f f e c t of Adsorbed Water on the Area of Benzene-D r i e d , KOH-Extracted C h l o r i t e H o l o c e l l u l o s e Moisture Regained, percentage B.E.T. Area, of ovendried weight sq. m. / g. 0.0 67.0 5-2 24.3 9.6 5.31 16.4 1.06 20.0 0.86 27-7 0.78 31.5 0.75 O r i g i n a l water-dried area 0.64 Merchant (12) a l s o found that atmospheric moisture must be r i g o r o u s l y excluded from the d r i e d sample to prevent large decreases i n the surface a v a i l a b l e to n i t r o g e n . Previous workers had not always taken t h i s p r e caution. Thode, Swanson and Becher (54) reported the r e s u l t s of n i t r o g e n adsorption on samples of wood pulp which had been solvent exchange d r i e d (water-methanol-n-pentane, with the pentane removed i n an atmosphere of dry n i t r o g e n at 35-5°C). The bleached s u l f i t e c e l l u l o s e was subjected to various degrees of beating i n a b a l l m i l l . The r e s u l t s they reported are given i n Table 6 and i n f i g u r e 9- In f i g u r e 9 t h e i r data are presented .as cumulative pore volume l e s s than a p a r t i c u l a r pore * From Haselton (13) F I G U R E 9 I N F L U E N C E O F B E A T I N G O N P O R E D I S T R I B U T I O N I N C E L L U L O S E F I B R E S AS D E T E R M I N E D B Y T H O D E . S W A N S O N A N D B E C H E R . ( 5 4 . ) T I M E B E A T E N 200 M I N . 1 0 0 M I N . 0 M I N . 60 80 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0 2 2 0 2 4 0 2 6 0 PORE RADIUS, « -31-r a d i u s . The c u m u l a t i v e p o r e v o l u m e s t h r o u g h o u t t h e b a l a n c e o f t h i s work a r e p r e s e n t e d as t h e p o r e v o l u m e o f p o r e s g r e a t e r t h a n a p a r t i c u l a r p o r e r a d i u s . T a b l e 6*: N i t r o g e n A d s o r p t i o n R e s u l t s on S o l v e n t Exchange, D r i e d F i b r e s - B.E.T. A r e a s a nd P o r e S i z e D I s t r i b u t Time T o t a l P o r e M e d i a n C a l c d . v o l . o o r e s o f A r e a A r e a p o r e 3 2 - 4 4 8 0 - 2 0 0 B a l l B.E.T. f r o m d i a m . ft ft M i l l M e t h o d P i e r c e ft.. d i a m . diam.' B e a t s q . c a l c d . ( l i q . ( l i q . i n g m./g. s q . • N 2 ) N 2 ) m i n . m./g. 0 1 0 0 95 3 8 . 0 0 . 0 5 5 0 0.0499 20 110 108 3 8 . 2 . 0 5 4 2 . 0 5 8 4 50 1 2 3 115 3 7 . 8 . 0 5 4 6 . 0 6 0 1 100 149 1 2 8 3 8 . 0 . 0 5 4 2 . 0 7 3 5 150 164 159 3 7 . 5 . 0 6 4 7 . 0 9 2 6 2 0 0 185 170 3 7 . 4 . 0 6 0 7 c l 4 4 7 2 5 0 2 0 2 178 3 8 . 5 . 0 6 5 7 . 1 1 5 3 The P i e r c e m e thod (48) was u s e d t o c a l c u l a t e t h e p o r e v o l u m e d i s t r i b u t i o n s . T h e s e a u t h o r s n o t e d t h e B.E.T. s u r f a c e a r e a o f t h e p u l p s . i s a l i n e a r f u n c t i o n o f t h e t i m e o f b e a t i n g . They c o n c l u d e d t h a t s i n c e t h e p o w e r i n p u t o f a b a l l m i l l i s e s s e n t i a l l y c o n s t a n t w i t h t i m e , t h i s phenomenon c o u l d be e x -p l a i n e d by R I t t i n g e r ' s l a w f o r s i z e r e d u c t i o n w h i c h s t a t e s t h a t new s u r f a c e d e v e l o p e d i s d i r e c t l y p r o p o r t i o n a l t o e n e r g y i n p u t . • * From ( 5 4 ) -32-The p l o t of cumulative pore volume versus pore s i z e ( f i g u r e 9) with the time of beating as a parameter i n -d i c a t e s increased pore volume began to show up at about 22 ft pore r a d i u s : below t h i s value, beating d i d not make very much d i f f e r e n c e except with severe and continued mechanical t r e a t -ment. However, the volumes of the l a r g e r pore s i z e s were found to have increased w i t h beating as i s shown i n Table 6 w i t h the 80-200 ft diameter pore volumes. As a r e s u l t of these phenomena, Thode et a l concluded that b a l l m i l l beating of wood c e l l u l o s e creates a d d i t i o n a l pores or f i s s u r e s i n the amorphous regions of the f i b r e , or at l e a s t enlarges e x i s t i n g pores a l l the way down to 50 ft or so i n diameter. The ob-s e r v a t i o n that the r e s u l t s of Haselton (13,50,51), Merchant (12,22), Hunt et a l (18) as w e l l as t h e i r own showed a break i n the desorption n i t r o g e n isotherm between r e l a t i v e pressure of 0.50 and 0.45 r e s u l t i n g i n a most common pore s i z e of.about 20 ft radius l e d to the conclusion that the 20 ft radius pore s i z e i s a c h a r a c t e r i s t i c of the f i n e s t r u c t u r e of c e l l u l o s e f i b r e s and may be r e l a t e d to the basic s t r u c t u r a l u n i t of c e l l u l o s e . They f u r t h e r hypothesized that the elementary b u i l d i n g blocks of " s o l i d " c e l l u l o s e are l a i d down i n some sort of array p e r m i t t i n g the r e g u l a r occurence of "holes" approxi-mately the s i z e of an elementary polymer u n i t . Sommers (5>55) i n an attempt to r e t a i n the highest p o s s i b l e surface area f o r a solvent exchange d r i e d cotton sample removed the f i n a l nonpolar l i q u i d , carbon d i o x i d e , as a gas above i t s c r i t i c a l temperature. The n i t r o g e n adsorption -33-Table J: B. E. T. Surface Areas of Samples Prepared by Sommers (5) • Sample Treatment n-Pentane d r i e d n-Pentane d r i e d COg removed above c r i t i c a l p oint ** CC>2 removed above c r i t i c a l p o int ** No treatment No treatment No treatment Gas Adsorbed Surface Area sq.m./g. N, N, N, H 20 H 20 H 20 46.8 5 1 . 8 51.8 5 2 . 8 128 136 140 * Sommers used c r o s s - s e c t i o n a l areas of 16.2 and 10.5 ft per molecule f o r N 2 and R^O r e s p e c t i v e l y . ** Highest values reported. Using a d i f f e r e n t source of C0 2 with 4 percent more moisture ( t o t a l moisture = 0.0647 mg. H 20 / g. C0 2) the surface area was lowered to 39.4 sq.m./g. This i n d i c a t e d a very high s e n s i t i v i t y to the moisture content of the C0„. : B.E.T. surface areas were found to d i f f e r l i t t l e from those found where n-pentane was the f i n a l l i q u i d . They were both lower than the B.E.T. areas c a l c u l a t e d from water vapour ad-s o r p t i o n . These r e s u l t s are given i n Table 7. Sommers (5 355) determined complete n i t r o g e n isotherms on a n-pentane d r i e d sample and two samples where the C 0 2 solvent was drawn o f f above the c r i t i c a l p o i n t . These isotherms are shown i n f i g u r e 10 and are l i s t e d i n t a b l e 4 of appendix C. A comparison of the pore s i z e d i s t r i b u t i o n s c a l c u l a t e d by the method of Pier c e (47) showed that despite lower B.E.T. surface areas, the C 0 2 d r i e d samples possessed a greater t o t a l pore volume than the n-pentane d r i e d sample. Most of the increased pore volume was i n the l a r g e r pore s i z e s . Table 8 gives these f i g u r e s . Table 8: Surface Area and Pore Volume f o r Isotherms Determined by Sommers (5,56) Sample D e s c r i p t i o n B.E.T. Area T o t a l Pore Volume determined at P/Po=0.971 (mis l i q u i d N 2) n-pentane d r i e d 46.9 0.0616 C 0 2 ( d r i e d by cotton) d r i e d 23.8 0.0745 C 0 2 d r i e d 39-4 0.0752 Some Russian workers, Odintsov and E r i n ' s h (56,57) studied the surface area and pore s i z e d i s t r i b u t i o n i n wood and pulp using benzene and hexane as the adsorbing gases. Their samples were prepared by solvent exchanging from water to -36-methanol and then to the hydrocarbon used f o r a d s o r p t i o n . In one paper (56) i n which only benzene was used as the ad-sorbate, surface areas of 300 and 450 sq.m./g. were r e -ported f o r sprucewood and spruce h o l o c e l l u l o s e r e s p e c t i v e l y . Pores having a r a d i u s of 30-1000 ft were reported to be almost completely absent i n the sprucewood but were present i n the h o l o c e l l u l o s e . In h o l o c e l l u l o s e the volume of pores having a r a d i u s of 15-80 ft were.found to predominate w i t h the maximum i n the pore volume d i s t r i b u t i o n o c c uring at 17-18 ft r a d i u s . Removal of the h e m i c e l l u l o s e s from the holo-c e l l u l o s e causes an increase i n the volume of pores having a radius of.over 200 ft. These f i n d i n g s , w i t h the exception of the high surface areas (10 and 200 sq.m./g. f o r sprucewood and h o l o c e l l u l o s e r e s p e c t i v e l y being the u s u a l l y accepted values) are s i m i l a r to those reported by others using n i t r o g e n , n-butane, e t c . as adsorbates. In another paper (57) benzene and hexane were used as adsorbates to study the " m i c r o c a p i l l a r y s t r u c t u r e of three c e l l u l o s e s . These c e l l u l o s e s were: h o l o c e l l u l o s e hydrolysed with 2.5 percent HCl at 100°C; h o l o c e l l u l o s e e x t r a c t e d w i t h 5 and 17-5 percent NaOH at20°C. Surface areas of 300-400 sq.m./g. were reported. Drying of the pulps r e s u l t e d i n an i r r e v e r s i b l e l o s s of 50 percent of the surface area. Ex-t r a c t i o n w i t h 17-5 percent NaOH Increased the volume of pores with 75-80 ft r a d i u s . A l l preparations showed a maximum i n the pore s i z e d i s t r i b u t i o n curves at a r a d i u s of 18 or 22 ft as determined from desorption isotherms of benzene or hexane r e s p e c t i v e l y . -37-Stone and S c a l l a n of the Pulp and Paper Research I n s t i t u t e of Canada have published a la r g e volume of work u t i l i z i n g n i t r o g e n adsorption to study the s t r u c t u r e of solvent exchange d r i e d pulps (16,33,58-61). Stone (58) i n 1963 published an extensive review of the l i t e r a t u r e concerned with the porous s t r u c t u r e of c e l l u l o s i c m a t e r i a l s . He reviewed microscopic ( p a r t i c u l a r l y e l e c t r o n ) , f l u i d f l ow, solute d i f f u s i o n , e l e c t r i c current flow as w e l l as gas adsorption and so l u t e a c c e s s i b i l i t y methods f o r studying pore s t r u c t u r e . As a r e s u l t of h i s survey, he con-cluded that i n s p i t e of the considerable work done employing a wide v a r i e t y of experimental techniques, the amount of r e l i a b l e data on the d e t a i l e d s t r u c t u r e of the porous nat i v e • c e l l u l o s e network was meagre and fragmentary. Stone and S c a l l a n (35) have reported on the e l e c t r o n micrograph and n i t r o g e n adsorption data upon which they based the p o s t u l a t e d s t r u c t u r e of the c e l l w a l l which was p r e v i o u s l y discussed i n s e c t i o n II-B of t h i s work. They used a t r a n s -mission e l e c t r o n microscope to study the f i b r e c r o s s - s e c t i o n s which were stained with phosphotungstic a c i d p r i o r to being embedded i n epoxy. The isotherm data was obtained using a dynamic s o r p t i o n apparatus of which the design and operation i s the subject of reference (62). They studied a number of d i f f e r e n t pulps and reported the B.E.T. surface area and "pore volume" as c a l c u l a t e d from the adsorption of n i t r o g e n at P/P Q = O.965. These r e s u l t s are given i n Table 9-The data of Table 9 y i e l d a l i n e a r r e l a t i o n s h i p between surface area and pore volume i n d i c a t i n g a constant median pore s i z e . Table 9: B. E. T. Areas and Pore Volumes f o r a V a r i e t y of C e l l u l o s i c M a t e r i a l s * Treatment Solvent exchanged from never d r i e d s t a t e Soaked, i n water and solvent exchange d r i e d Dried from water at 105 °C Sample B.E.T. Surface Area sq.m./g. Pore Volume 0 - 300 ft 'ra< cc./g. Unbleached spruce k r a f t 230 0.39 Unbleached spruce s u l p h i t e 182 0.31 Spruce c e l l u l o s e 185 0.30 Bleached spruce k r a f t 185 0.295 Yellow b i r c h k r a f t 129 0.22 Bleached spruce s u l p h i t e 93 0.18 Spruce groundwood 25 0. 040 Sprucewood (microtome sections) 3 to 6 (0.006) Sprucewood (microtome sections) 0.6 to 0.8 — Unbonded pulp f i b r e s 1.2 0.002 Paper 0.5 to 1.0 * From Stone and S c a l l a n (35) -39-The ad s o r p t i o n and desorption isotherms f o r the solvent exchange d r i e d f i b r e s were analysed by the Pi e r c e (48) method and In both cases, the most common pore ra d i u s was found to be i n the 16-20 ft range f o r a l l samples. They determined the median pore s i z e (defined as the pore s i z e at which one h a l f of the t o t a l pore volume i s contained i n smaller pores"and one h a l f i n l a r g e r pores) by two methods: from the cummulative d i s t r i b u t i o n curve and from the r e l a t i o n -s h i p . rmed = 2 X(0.965) (1.) A A good c o r r e l a t i o n between the methods was found w i t h the values determined ranging between 32 and 38 ft. Their e l e c t r o n micrographs (35) showed that the c e l l w a l l has a tendency to s p l i t i n t o lamellae ( p o s s i b l y caused by s w e l l i n g of the epoxy embedding r e s i n i n pores between lam e l l a e ) and these lamellae are more or l e s s c o n c e n t r i c with the f i b r e a x i s . The l o s s of surface area ( n i t r o g e n adsorption) of solvent exchange d r i e d wood pulp , c e l l u l o s e , x y l a n and l i g n i n w i t h heating was the subject of another paper by Stone and S c a l l a n (59). Changes i n the pore s i z e d i s t r i b u t i o n of bleached spruce s u l p h i t e pulps were a l s o discussed. The experimental technique i n v o l v e d a water-methanol-hexane solvent exchange with the hexane removed at room temperature i n a stream of d r i e d n i t r o g e n . The surface area was then measured and the sample heated to the d e s i r e d temperature i n an a i r bath f o r 30 minutes while being purged with a dry -40-helium-nitrogen mixture. The r e s u l t s of these experiments on a v a r i e t y of c e l l u l o s i c m a t e r i a l s i n d i c a t e d a decrease i n surface area w i t h i n c r e a s i n g treatment temperature. A very sharp l o s s of surface area w i t h temperature s t a r t i n g at about 175 °C f o r l i g n i n and 195° f o r x y l a n was a l s o noted and these were thought to be r e l a t e d to the thermal s o f t e n i n g temperatures of these m a t e r i a l s of about 195°C and 217°C r e s p e c t i v e l y as measured by Goring (63). Merchant (22) showed th a t higher s p e c i f i c surface areas are obtained from a sample i f the surface t e n s i o n of the f i n a l s o lvent i s reduced d u r i n g evaporation by r a i s i n g the d r y i n g temperature. He a l s o p o i n t e d out tha t prolonged ex-posure to temperatures above 60°C r e s u l t e d i n l o s s of surface area. Stone and S c a l l a n (59) prepared.three samples w i t h the hexane being removed at 0, 25, and 50°C. A marked i n -crease of surface area w i t h i n c r e a s e d d r y i n g temperature was noted. These samples a l l r e v e r t e d to the same surface area when heat t r e a t e d at l80°C. The changes i n pore surface area d i s t r i b u t i o n were measured by these.workers (59). One e f f e c t of heating a solvent exchange d r i e d pulp i s l o s s of pore volume, w i t h the grea t e s t percentage l o s s being i n the pores of l e s s than 25 ft r a d i u s . Samples which had been heated t o e l e v a t e d temperatures a f t e r s o l v e n t exchange d r y i n g , and which had l o s t a l a r g e percent of t h e i r surface areas, r e v e r t e d to t h e i r o r i g i n a l s olvent exchange d r i e d surface areas when soaked i n water and solvent exchange d r i e d a second time. X-ray d i f f r a c t i o n data and scanning e l e c t r o n . - I l l -micrographs of the samples before and a f t e r h eating showed no s i g n i f i c a n t d i f f e r e n c e s except f o r a more v i t r i f i e d appearance of the heated specimens i n the micrographs. The vapours d r i v e n o f f d uring heat treatment were analysed with a gas chro-matograph. Hexane was evolved at the lowest temperature w i t h water e v o l u t i o n commencing at about 100°C. Both m a t e r i a l s e s s e n t i a l l y ceased e v o l u t i o n at l45°C. Very l i t t l e methanol was detected and no carbon monoxide and carbon d i o x i d e , even at 200°Cj the d e t e c t i o n of which would have i n d i c a t e d that the c e l l u l o s e was breaking down. At the symposium " C o n s o l i d a t i o n of the Paper Web" held at Cambridge, England,'in September, 19-65, Stone and S c a l l a n (16) presented a paper w i t h the s t a t e d purpose of examining i n d e t a i l the exact manner i n which water i s accommodated w i t h i n the c e l l w a l l of a pulp f i b r e . These workers i n d i c a t e d three p o s s i b i l i t i e s f o r t h i s accommodation of water: i . I t could enter c a p i l l a r i e s already present i n the dry f i b r e i i . I t could form c a p i l l a r i e s or pores by s e p a r a t i n g surfaces that were p r e v i o u s l y j o i n e d i i i . I t could form a molecular a s s o c i a t i o n w i t h the c e l l w a l l components, i n e f f e c t d i s s o l v i n g i n them producing no r e a l s u r f a c e s . These three p o s s i b i l i t i e s were examined s e p a r a t e l y . i . Low angle s c a t t e r i n g of X-rays (64,65) and n i t r o g e n a d s o r p t i o n (35) techniques have been used to show the exis t e n c e of a small ( l e s s than 0 . 5 $ ) volume of pores i n the s i z e range of 20-300 & equ i v a l e n t r a d i u s i n dry n a t i v e c e l l u l o s i c f i b r e s . Mercury i n t r u s i o n techniques have a l s o been used (66) and wit h these i t was found that the volume of pores smaller than 0.3 microns was l e s s than 0.02 c.c./g i n dry bleached spruce s u l p h i t e pulp f i b r e s . Pores l a r g e r than 0.3 microns should be v i s i b l e m i c r o s c o p i c a l l y but o p t i c a l and scanning e l e c t r o n micrographs (16) have f a i l e d to r e v e a l any such pores. Thus i t was concluded that pores do e x i s t w i t h i n the c e l l w a l l of dry n a t i v e c e l l u l o s e , but as t h e i r t o t a l volume i s s m a l l , they should have l i t t l e i n f l u e n c e on the r e -l a t i o n s h i p between water uptake and the r e s u l t i n g change i n c e l l w a l l dimensions. The r e s u l t s of s e v e r a l workers(17-19, 22,35, 4 l , 51, 5^, 55) who have s t u d i e d n a t i v e c e l l u l o s e f i b r e s by solvent exchange d r y i n g and gas adso r p t i o n have l e d to general agreement on the f o l l o w i n g p o i n t s as expressed by Stone and S c a l l a n : (a) The s p e c i f i c surface area of f i b r e s d r i e d from water i s about 1 sq.m./g. (b) The s p e c i f i c surface area of water-swollen f i b r e s d r i e d by solvent exchange i s many times greater than 1 sq. m./g., values ranging up to 200 sq. m./g. (c) The pores that are r e s p o n s i b l e f o r the large surface area of swollen f i b r e s are s m a l l , the most common pore s i z e being of the order of 16-22 ft r a d i u s and the median pore s i z e (that s i z e above and below which e x i s t s 50 percent of the t o t a l volume) i s about 35 ft r a d i u s . The l a r g e d i f f e r e n c e i n s u r f a c e a r e a s a s r e c o g n i z e d by n i t r o g e n m o l e c u l e s b e t w e e n a n a i r d r i e d f i b r e a n d a s o l v e n t e x c h a n g e d r i e d f i b r e i n d i c a t e s s u r f a c e a r e a must be c o n t a i n e d w i t h i n t h e w a l l i t s e l f , p r e s u m a b l y as t h e s u r f a c e o f p o r e s t h a t w e re p r o d u c e d by t h e s e p a r a t i o n o f s t r u c t u r a l e l e m e n t s as w a t e r e n t e r e d . The w a t e r h e l d i n t h e s e p o r e s must h a v e some o f t h e b u l k w a t e r p r o p e r t i e s a s i t c a n m i x w i t h a n d be r e -p l a c e d by o t h e r m a t e r i a l s d u r i n g s o l v e n t e x c h a n g e d r y i n g . Thus i t was c o n c l u d e d t h a t w a t e r c o u l d o p e n p o r e s by s e p a r a t i n g s u r f a c e s t h a t w e re p r e v i o u s l y j o i n e d . S t o n e a nd S c a l l a n ( 1 6 ) d e t e r m i n e d t h e c h a n g e s i n t o t a l p o r e v o l u m e o f p u l p f i b r e s w i t h d e c r e a s i n g m o i s t u r e c o n t e n t by n i t r o g e n a d s o r p t i o n on s a m p l e s w h i c h h a d b e e n s o l v e n t e x c h a n g e d r i e d f r o m t h e v a r i o u s m o i s t u r e c o n t e n t s . T h e i r ' r e s u l t s a r e l i s t e d i n t a b l e 10. They f o u n d t h e p o r e v o l u m e o f t h e d r i e r p u l p s ( l e s s t h a n 40 p e r c e n t m o i s t u r e ) d e t e c t e d by n i t r o g e n a d s o r p t i o n was o n l y o n e - f i f t h o f t h e v o l u m e o f t h e w a t e r p r e s e n t i n t h e p u l p f i b r e s p r i o r t o t h e s o l v e n t e x c h a n g e d r y -i n g . T h u s , as a s u b s t a n t i a l f r a c t i o n o f t h e w a t e r p r e s e n t i n p u l p f i b r e s i s n o t f o u n d i n p o r e s d e t e c t a b l e by gas a d s o r p t i o n t e c h n i q u e s i t was c o n c l u d e d t h i s w a t e r must f o r m some t y p e o f m o l e c u l a r a s s o c i a t i o n w i t h t h e c e l l u l o s e m o l e c u l e s . R e c e n t l y , t h e s e w o r k e r s h a v e p u b l i s h e d some a c c e s s i b i l i t y r e s u l t s w h i c h i n d i c a t e -44-Table 10: Porous Structure at Various Stages of Drying at 25°C Water present before S p e c i f i c Surface, Pore volume, cm /g i n solvent exchange dr y i n g * 3 percent cm /g. sq.m./g. pores to 300 ft B.E.T. Pie r c e Experimental P i e r c e 95 20 93 - 0.160 -64 1.78 93 109 0.160 0.176 47 0.89 89 104 0.155 0.156 42 0.725 65 69 0.120 0.120 28 0.39 51 ; 54 0.080 0.075 24 0.315 51 46 ' 0.068 0.064 13 0.15 24 22 0.033 0.030 4 0.04 7 - 0.007 - ; 0 0.00 1 0.002 Percentage water c a l c u l a t e d as (weight of water x 100)/ (weight of s o l i d s + water) 3 Volume of ni t r o g e n ( i n cm l i q u i d ) sorbed by the sample at p/p =0.965 t h i s c o n c l u s i o n may be i n c o r r e c t . These r e s u l t s are discussed i n s e c t i o n s II-K and IV-D. At the Cambridge symposium Stone and S c a l l a n pre-sented the r e s u l t s of some experiments determining the changes i n area and pore volume w i t h d r y i n g . These experiments were done on two s e r i e s of pulp samples. One s e r i e s was d r i e d to a measured water content and then solvent exchange d r i e d using the water-methanol-pentane sequence with the pentane removed i n a stream of dry n i t r o g e n at 25°C. The second s e r i e s was d r i e d to a known moisture content, soaked i n water overnight and then solvent - exchange d r i e d . Nitrogen adsorption isotherms were determined on a l l samples and B.E.T. and a Pie r c e a n a l y s i s made. The r e s u l t s of these experiments are given i n Tables 10 and 11 and Figure 11. The r e s u l t s of these experiments l e d Stone and S c a l l a n to the co n c l u s i o n that there are apparently two types of pores of about equal volume. One type closed i r r e v e r s i b l y during d r y i n g , commencing at about 50 percent moisture and became more or l e s s completely closed at 30 - 40 percent moisture. The , second type, which can be reopened with water, s t a r t e d to close at 30-40 percent moisture and continued to close u n t i l complete dryness was reached. Examination of the pore s i z e d i s t r i b u t i o n s by these workers revealed the d i f f e r e n c e between the r e v e r s i b l e and i r r e v e r s i b l e c l o s i n g pores was not based on s i z e as there were no s i g n i f i c a n t d i f f e r e n c e s i n pore s i z e d i s t r i b u t i o n s w i t h decreasing moisture content. -46-F I G U R E I I . ( R E D R A W N F R O M R E F E R E N C E 16.) C H A N G E O F P O R E V O L U M E D U R I N G D R Y I N G O P A R T I A L L Y D R I E D V P A R T I A L L Y D R I E D A N D R E S W O L L E N 20 40 60 P E R C E N T A G E W A T E R » 80 O -100 - 4 7 -T a b l e 11: Porous S t r u c t u r e Developed A f t e r P a r t i a l D r y i n g at 25 C and R e s w e l l i n g i n Water Water* t o which S p e c i f i c s u r f a c e , Pore volume, cm /g i n f i b r e s r educed b e f o r e sq.m./g. pores t o 300 ft r e s w e l l i n g , p e r cent B.E.T. P i e r c e E x p e r i m e n t a l * * P i e r c e V •P 48 83 89 0.150 0.150 47 80 93 0.158 0.162 42 87 93 0.145 0.145 37 75 73 0.131 0.128 28 59 57 0.100 0.100 24 51 57 0.088 0.087 15 52 46 0.090 0.084 13 53 51 0.083 0. 080 4 55 55 . 0.080 0.076 0 55 _ 0.080 _ * Per c e n t a g e water c a l c u l a t e d as (weight o f water x 1 0 0 ) / (weight o f s o l i d s + water) ** Volume o f n i t r o g e n ( i n cm l i q u i d ) sorbed by the sample, at p/p^ = 0.965 -48-G - I n t e r p r e t a t i o n of Gas Adsorption Results i n Terms of The P a r a l l e l Sided F i s s u r e Model of C e l l u l o s e S t r u c t u r e .  Stone and S c a l l a n discussed these r e s u l t s i n terms of the model of c e l l u l o s e f i b r e they proposed and which has been described i n s e c t i o n II-B of t h i s work. They po s t u l a t e d 'that dry i n g could cause lamellae to move together and cause the spaces between them to c l o s e completely, one a f t e r another, r a d i a l l y inward from the e x t e r i o r of the f i b r e toward the lumen. Pores would thus be e i t h e r completely open or completely c l o s e d , except i n the t r a n s i t i o n zone, which, i f narrow enough, would be i n s u f f i c i e n t to a f f e c t the d i s t r i b u t i o n of pore s i z e s . In support of t h i s model there i s the work of Hermans (67) and Greyson and L e v i (68). Hermans (67) reported that the r e -verse process, moistening of a dry rayon f i l a m e n t , proceeds r a d i a l l y inward from a sharply defined moistened mantle to the core of the filament which r e t a i n s i t s i n i t i a l moisture con-t e n t . - Greyson and L e v i , (68) s t a r t i n g with water swollen cotton f i b r e s solvent exchange d r i e d , measured the surface area by n i t r o g e n a d s o r p t i o n , t r e a t e d the sample with a small amount of water vapour, evaporated the water and remeasured the surface area. The second surface area was l e s s than the o r i g i n a l . A d d i t i o n a l treatments with water vapour had no e f f e c t on the surface area u n t i l the amount of moisture added exceeded that of the f i r s t a d d i t i o n . This r e s u l t i m p l i e s that water enters the same region of the f i b r e on successive a d d i t i o n s as i t d i d on the i n i t i a l a d d i t i o n and swells these r e g i o n s , only moving deeper i n t o the f i b r e when the a d d i t i o n of water ex-ceeds that p r e v i o u s l y added. -49-H - D i s t r i b u t i o n of Water i n the C e l l Wall Stone and S c a l l a n (16) used Figure 12 to show a p p r o x i -mately where the water was d i s t r i b u t e d i n the bleached spruce s u l p h i t e pulp at various moisture contents. The data of Table 10 show the pore volume measured at any stage of d r y i n g i s con-s i d e r a b l y l e s s than the volume of water present p r i o r to solvent exchange d r y i n g . At low moisture content ( l e s s than 40%). the pore volume measured i s a constant f r a c t i o n ( o n e - f i f t h ) of the water present, assuming water r e t a i n s a de n s i t y of 1.0 gm./c.c. Thus i f , the four f i f t h s water i s not i n pores, i t must be. pre-sent i n the " s o l i d " lamellae as g e l or mo l e c u l a r l y bound water and i s removed during solvent exchange without l e a v i n g pore ; space. I n t e r e s t i n g l y , the so l u t e a c c e s s i b i l i t y method (69) (discussed i n sections II-K and IV-D) determines a t o t a l pore volume of about 5 times the pore volume detected by gas adsorption. With the small molecular probes (Einstein-Stokes diameter of 8 ft) v i r t u a l l y a l l of t h i s pore volume i s a c c e s s i b l e , i n d i c a t i n g the water i s held i n some form of pore. Thus, i t would appear that a large p o r t i o n of the pores could be l o s t when a pulp is- solvent exchange d r i e d . I - E f f e c t of Beating on Surface Area of Solvent Exchange Dried Pulps  These workers (16) a l s o studied the e f f e c t of beating on surface area of pulps that were: never d r i e d ; d r i e d over P 2 0 5 at 25 °C; d r i e d at 105 °C; and d r i e d at 105 °C followed by heat treatment at 150 °C. A l l the pulps were reswollen with -50-FIGURE 12. (REDRAWN FROM REFERENCE 16) THE DISTRIBUTION OF WATER IN PULP FIBRES PERCENT WATER w a t e r a n d s o l v e n t e x c h a n g e d r i e d p r i o r t o s u r f a c e a r e a d e t e r m i n a t i o n . The r e s u l t s a r e shown i n f i g u r e 4 l . I n a l l c a s e s , t h e s u r f a c e a r e a i n c r e a s e d w i t h t h e amount o f b e a t i n g . J - The I n f l u e n c e o f C o m p o s i t i o n on P o r o s i t y and S u r f a c e A r e a A s t u d y o f t h e i n f l u e n c e t h e c o m p o s i t i o n o f t h e f i b r e h a s on i t s p o r o s i t y and d r y i n g b e h a v i o r was a l s o made. The m a t e r i a l s u s e d i n c l u d e d s p r u c e b l e a c h e d and u n b l e a c h e d k r a f t a n d s u l p h i t e p u l p s , a s p r u c e a l p h a c e l l u l o s e , a h o l l o w f i l a m e n t r a y o n and a s p r u c e g r o u n d w o o d f r a c t i o n i n t h e n e v e r d r i e d s t a t e a nd d r i e d f o r one h o u r a t 105°C and r e s w o l l e n . > B.E.T. s u r f a c e a r e a s and p o r e a n a l y s i s were done on a l l t h e s o l v e n t e x c h a n g e d r i e d s a m p l e s . The p o r e s i z e d i s t r i b u t i o n s f o r a l l s p e c i m e n s were v e r y s i m i l a r w h i c h l e d S t o n e and S c a l l a n t o s u g g e s t t h a t t h e p o r e s i n n a t i v e f i b r e s h a v e a d i s -t r i b u t i o n o f s i z e s n o t b i o l o g i c a l l y c o n t r o l l e d n o r a f u n c t i o n o f c h e m i c a l t r e a t m e n t b u t r a t h e r b a s e d on some p r o p e r t y of. t h e c e l l u l o s e m o l e c u l e w h i c h c a u s e s i t t o a g g r e g a t e i n t o c e r t a i n p r e f e r r e d a r r a n g e m e n t s . The s h i f t o f t h e m e d i a n p o r e s i z e t o a l o w e r v a l u e when t h e s a m p l e s a r e d r i e d a t 105 °C and r e s w o l l e n i n w a t e r was a t t r i b u t e d t o a more permament c l o s u r e o f t h e p o r e s o f l a r g e r s i z e . T h i s e f f e c t was c o n s i d e r e d t o be a r e s u l t o f t h e e a s i e r p l a s t i c d e f o r m a t i o n o f l a r g e r p o r e s by a m e c h a n i s m s i m i l a r t o t h e s t r e s s r e l a x a t i o n i n d r i e d f i b r e s w i t h i n c r e a s i n g t e m p e r a t u r e as r e p o r t e d by R o b e r t s o n (70). S t o n e and S c a l l a n (60) p e r f o r m e d a s e r i e s o f e x p e r i m e n t s -52-to d e s c r i b e the changes of p o r o s i t y of wood pulp w i t h de-c r e a s i n g y i e l d . Wood meal and groundwood pulp were de-l i g n i f i e d by chlorine-monoethanolamine treatments which were presumed to remove only the l i g n i n l e a v i n g the h o l o c e l l u l o s e . The groundwood pulp and wood meal had i n i t i a l s u rface areas of about 40 and 5 sq.m./g. r e s p e c t i v e l y . The surface area and p o r o s i t y as determined by so l v e n t exchange d r y i n g and n i t r o g e n a d s o r p t i o n i n c r e a s e d w i t h decreasing l i g n i n content, r e t a i n i n g approximately the d i f f e r e n c e i n i n i t i a l v a l u e s . In the second set of experiments the surf a c e area and p o r o s i t y of k r a f t and s u l p h i t e b l a c k spruce pulps of v a r i o u s y i e l d s were monitored by solvent exchange d r y i n g and n i t r o g e n ad-s o r p t i o n . T h e i r r e s u l t s were i n t e r p r e t e d as: The removal of l i g n i n or l i g n i n and carbohydrate from wood f i b e r s leaves s m a l l pores i n the swollen c e l l w a l l . These have a median s i z e which covers the range from 20-40A\ 2. As m a t e r i a l i s removed from the c e l l w a l l , the p o r o s i t y i n c r e a s e s from p r a c t i c a l l y 0 at 100% y i e l d and reaches a maximum at 65-70% y i e l d , , at which p o i n t the swo l l e n c e l l w a l l contains s l i g h t l y more v o i d than s o l i d volume. According to the m u l t i l a m e l l a r concept, the developing p o r o s i t y i s i n t e r p r e t e d as the pro-g r e s s i v e s u b d i v i s i o n of the c e l l w a l l i n t o t h i n n e r and t h i n n e r lamellae u n t i l at the maximum these are only 35-40 R. t h i c k . The pores are then the s l i t - l i k e spaces between these l a m e l l a e , and i n c r e a s e w i t h the number of l a m e l l a e . 3. I f the pore volume i s compared w i t h the volume of m a t e r i a l removed from the c e l l w a l l , i t i s found that the p o r o s i t y vs. y i e l d curves may be d i v i d e d i n t o three zones. From 90-100% y i e l d , the pore volume i s approx-i m a t e l y equal to the volume of m a t e r i a l removed. From 67-90% y i e l d , the pore volume exceeds the volume of m a t e r i a l removed, that i s , s w e l l i n g of the c e l l w a l l occurs. T h e r e a f t e r , the s w e l l i n g decreases u n t i l below 55% y i e l d the pore volume i n d i c a t e s a net con-t r a c t i o n of the c e l l w a l l . This c o n t r a c t i o n of the c e l l w a l l towards the end of d e l i g n i f i c a t i o n may be the r e v e r s a l of the s w e l l i n g caused dur i n g growth by the -53-i n t u s s u s c e p t i o n o f l i g n i n . K - S o l u t e A c c e s s i b i l i t y o f C e l l u l o s i c M a t e r i a l s I n a s e r i e s o f papers (69,71-74) Stone e t a l used s o l u t e a c c e s s i b i l i t y t o st u d y a wide v a r i e t y o f c e l l u l o s e p r o p e r t i e s . I n c l u d e d are s t u d i e s o f the s w e l l i n g b e h a v i o r o f k r a f t and s u l p h i t e b l a c k s pruce p u l p s a t d i f f e r e n t y i e l d s , o f n e v e r d r i e d and d r i e d and r e s w o l l e n b l e a c h e d p i n e s u l p h a t e p u l p , o f b l e a c h e d p i n e k r a f t and s u l p h i t e p u l p s and p u l p f r a c t i o n s s u b j e c t e d t o v a r i o u s degrees of. P . F . I , m i l l b e a t i n g , and o f r e g e n e r a t e d c e l l u l o s e . The s o l u t e e x c l u s i o n t e c h n i q u e measures t h e volume o f water i n a c c e s s i b l e t o polymer m o l e c u l e s o f d i f f e r i n g h y d r o -dynamic d i a m e t e r s as c a l c u l a t e d by t h e E i n s t e i n - S t o k e s , f o r m u l a . D iameter = — — (2) 3TT nDN Q T a b l e 12 g i v e s the c h a r a c t e r i s t i c s o f t h e macromolecules used by Stone e t a l (69, 72-74). A known t o t a l w e i g h t o f t h e porous c e l l u l o s i c m a t e r i a l , s w o l l e n i n an e x c e s s o f w a t e r , has a measured volume o f a s o l u t i o n o f one o f t h e t e s t m a t e r i a l s added. The system i s s e a l e d and mixed t h o r o u g h l y a l l o w i n g t ime f o r t h e macromole-c u l e s t o d i f f u s e i n t o the pore s t r u c t u r e . A f t e r e q u i l i b r i u m i s o b t a i n e d , a sample o f the l i q u i d i s removed f o r a n a l y s i s o f t h e c o n c e n t r a t i o n o f s o l u t e , t h e c e l l u l o s i c m a t e r i a l i s washed, d r i e d and weighed t o d e t e r m i n e the amount o f water i n i t i a l l y p r e s e n t . I f a l l the water o r i g i n a l l y a s s o c i a t e d -54-T a b l e 12 *: P r o p e r t i e s o f Macromolecules Used by Stone and S c a l l a n Macromolecule M o l e c u l a r weight M w M w M n M o l e c u l a r d i a m e t e r i n s o l u t i o n , ft Glucose 180 1.0 8 Ma l t o s e 342 1.0 10 R a f f i n o s e 504 1.0 12 Stachyose 666 1.0 14 D e x t r a n 1. 4 1400 1.3 20 2. 6 2600 1.3 26 5. 4 5400 1.3 36 8. 8 8800 1.4 45 10 11,200 2.0 51 20 21,800 . 1.5 68 40 39,800 1.5 90 100 100,500 1.6 140 500 420,000 2.7 270 2,000 2 x 1 0 6 - 560 24,000 24 x 1 0 6 — 1600 * Prom r e f e r e n c e (69) -55-w i t h the porous body i s a c c e s s i b l e to the s o l u t e molecules, i t w i l l a l l c o n t r i b u t e to the d i l u t i o n of the s o l u t i o n . I f the s o l u t e molecules are too la r g e to enter the sma l l e r pores, the water i n these pores i s u n a v a i l a b l e f o r d i l u t i o n , and the s o l u t i o n a f t e r mixing w i l l be somewhat l e s s d i l u t e than i n the f i r s t case. This d i f f e r e n c e i n c o n c e n t r a t i o n i s the b a s i s of a simple c a l c u l a t i o n to give the amount of water i n -a c c e s s i b l e to the s o l u t e . When the s o l u t e molecules are too l a r g e to enter the pore s t r u c t u r e at a l l , the i n a c c e s s i b l e water equals the t o t a l water of s w e l l i n g . Figure 13 demon-s t r a t e s the type of data o b t a i n a b l e by t h i s method. Some of these are given i n t a b l e 6 of appendix C. In the study by a c c e s s i b i l i t y measurements on the s w e l l i n g behavior of k r a f t and s u l p h i t e b l a c k spruce pulps of a wide range of y i e l d s , Stone and S c a l l a n ( 69 ) found that both p u l p i n g processes could be d i v i d e d i n t o two stages; from 100 to 60 percent y i e l d and below 60 percent y i e l d . In the k r a f t p u l p s , the wet c e l l w a l l stayed constant i n volume down to 60 percent y i e l d , w i t h water r e p l a c i n g the s o l i d m a t e r i a l l e a v i n g the w a l l . However, f o r the s u l p h i t e pulps over the same y i e l d range the c e l l w a l l s t e a d i l y s w elled as components were removed. These workers p o s t u l a t e d that t h i s d i s r u p t i o n of the s t r u c t u r e of s u l p h i t e f i b r e s may account f o r the s u l p h i t e pulp being weaker than the eq u i v a l e n t k r a f t pulp. As the y i e l d was lowered below 60 percent, the c e l l w a l l s of both k r a f t and s u l p h i t e pulp f i b r e s c o n t r a c t e d . The s u l p h i t e pulp f i b r e s always contained more water than the k r a f t at a FIGURE 13. THE ACCESSIBILITY DATA OF STONE AND SCALLAN (69 ) (PHOTO) -57-p a r t i c u l a r y i e l d . Within the c e l l w a l l , the water was contained i n pores whose average s i z e increased as p u l p i n g proceeded; those i n the s u l p h i t e pulp f i b r e s always being somewhat l a r g e r than the k r a f t f i b r e s of equivalent y i e l d . A comparison between the r e s u l t s f o r pulps of v a r i o u s y i e l d s reported by these workers (60) using n i t r o g e n a d s o r p t i o n on solvent exchange d r i e d pulp and the data obtained from t h e i r a c c e s s i b i l i t y method r e v e a l s some major descrepancies. Most obvious of these d i s c r e p a n c i e s i s the t o t a l pore volume, which i f determined by the a c c e s s i b i l i t y method i s at l e a s t twice that determined by gas adsorption techniques. The gas adsorption method i n d i c a t e s a maximum pore volume occurs at about 60-70 percent y i e l d , decreasing r a p i d l y w i t h f u r t h e r p u l p i n g . The a c c e s s i b i l i t y data i n d i c a t e the t o t a l pore volume increa s e s as the y i e l d de-creases throughout the range s t u d i e d (100-50 percent y i e l d ) . These d i s c r e p a n c i e s may be i n t e r p r e t e d as i n d i c a t i n g pore c o l l a p s e during solvent exchange d r y i n g , which i s hindered where the y i e l d i s 60-70 percent by the presence of sub-s t a n t i a l q u a n t i t i e s of the l i g n i n and other n o n c e l l u l o s e components of the wood. At higher y i e l d s both methods i n -d i c a t e a lower pore volume. At lower y i e l d s , the non-c e l l u l o s e components are not present i n s u f f i c i e n t q u a n t i t y to a r r e s t the c o l l a p s e of the pores during solvent exchange dr y i n g . In s t u d i e s of a c c e s s i b i l i t i e s on pine p u l p s , St-one et a l (72,73) found that the pore volume d i s t r i b u t i o n below 25 ft was e s s e n t i a l l y i d e n t i c a l f o r never d r i e d pulp, d r i e d and r e -- 5 8 -swolien p u l p , beaten pulp and pulps cooked by the k r a f t or s u l p h i t e processes. For pores a c c e s s i b l e to molecules of 25 to 560 ft diameter, d r y i n g and r e s w e l l i n g caused a sub-s t a n t i a l decrease. Beating i n i t i a l l y caused a s l i g h t i n -crease i n s w e l l i n g of never d r i e d k r a f t p u l p s , however, f u r t h e r beating caused no more s w e l l i n g . The s w e l l i n g of pores a c c e s s i b l e to molecules 25-560 ft diameter w i t h beating increased c o n t i n u o u s l y , and was more pronounced w i t h the s u l p h i t e pulp. As wi t h spruce wood, the s u l p h i t e pulp always contained more water. With the exception of the f i n e s ( l e s s than 100 mesh) a l l f i b r e f r a c t i o n s obtained from a beaten pulp were swollen to the same extent. The f i n e s f r a c t i o n was swollen to a much gre a t e r extent. These con-c l u s i o n s have been s u b s t a n t i a t e d by gas ad s o r p t i o n r e s u l t s (16,54) as to the e f f e c t of be a t i n g on pore volume. The s o l u t e e x c l u s i o n technique was a l s o a p p l i e d to water swollen cellophane, t e x t i l e rayon and super t i r e c o r d by Stone et a l (74). The shape of the pore volume d i s -t r i b u t i o n i s very s i m i l a r to that found f o r wood pulp. In the never d r i e d s t a t e , the maximum pore s i z e s were about 200, 100 and 50 ft wi t h median pore s i z e s approximately 40, 25 and 12 ft r e s p e c t i v e l y . Smaller values were obtained a f t e r d r y i n g and r e s w e l l i n g . The undried cellophane contained about twice the water i n a c c e s s i b l e to large molecules as did wo o d pulp . T e x t i l e rayon had about the same i n a c c e s s i b l e volume as wood pulp and super t i r e c o r d had co n s i d e r a b l y l e s s . -59-I I I - INTER F I B R E BONDING AND MEASUREMENT OF BONDED AREA I f one s t u d i e s a water s l u r r y of pulp f i b r e s i t Is p o s s i b l e to d i s c e r n the separate i n d i v i d u a l pulp f i b r e s . In the paper making process, s l u r r i e s of pulp f i b r e s are drained on a f i n e screen to remove most of the water, and the r e s u l t i n g wet web i s a i r d r i e d to produce'a cohesive sheet of paper. The p h y s i c a l p r o p e r t i e s of t h i s sheet are dependent on what t r e a t -ment the pulp f i b r e s may have r e c e i v e d and what a d d i t i v e s there are present i f any. I f one s t u d i e s the sheet of paper, i n d i v i d u a l f i b r e s may s t i l l be d i s c e r n e d , but they are now attached to the mass of the' sheet. The attachment i s probably due p a r t l y to f i b r e and f i b r i l entanglement, but most of the s t r e n g t h of attachment i s a t t r i b u t e d to f i b r e - t o - f i b r e bonds.' Marrinan and Mann (75) used d e u t e r a t i o n and i n f r a -red spectroscopy to show that a l l the OH groups i n c r y s t a l l i n e regions of regenerated and b a c t e r i a l c e l l u l o s e s are hydrogen bonded. (The i n t e r a c t i o n between c e l l u l o s e and heavy water allows absorptions due to s t r e t c h i n g of OH groups i n c r y s t a l l i n e and amorphous regions to be s t u d i e d s e p a r a t e l y , however, t h i s method does not enable one to separate the • absorptions due to separate f i b r e s ) . Corte et a l (76) using an experimental procedure of stepwise d e u t e r a t i o n have shown that the mechanical s t r e n g t h of paper i s caused by hydrogen bonds between the f i b r e s . The f i b r e - t o - f i b r e bonds have been s t u d i e d f o r many years and the exact nature of the formation of these bonds has eluded c o n c l u s i v e proof. I t i s g e n e r a l l y acknowledged that -60-tho a c t u a l i n t o r f i b r e bondo are due to hydrogen bonding (76,77). Thus the i n t e r f i b r e bonding i s dependent on the same f o r c e s t h a t cause the c o l l a p s e o f pores and i r r e v e r s i b i l e bonding of some l a m e l l a e i n a s i n g l e f i b r e when i z i s d r i e d from water. A number of methods have been d e v i s e d t o measure the area of i n t e r f i b r e bonds, a r a t h e r fundamental p r o p e r t y of paper. Some o f . t h e s e methods a r e : gas a d s o r p t i o n (12, 78-8D); l i g h t s cattering. ( 7 9 - 8 6 ), p o l a r i z e d l i g h t m icroscopy (87-89) and d i r e c t c u r r e n t . e l e c t r i c a l c o n d u c t i v i t y (90). Of these methods, l i g h t s c a t t e r i n g and gas a d s o r p t i o n have been the most commonly used. Measurement of the bonded ar e a by p o l a r i z e d l i g h t and a microscope i s the onl y method which g i v e s a d i r e c t r e a d i n g of bonded a r e a . However t h i s technique cannot d i s t i n g u i s h between a c t u a l c o n t a c t (remember t h a t H bond l e n g t h s are around 4ft) of two s u r f a c e s and s u r f a c e s s e p a r a t e d by l e s s than a p p r o x i m a t e l y one h a l f of the wavelength of the l i g h t used ( i . e . about 18OO ft s e p a r a t i o n ) . Gas a d s o r p t i o n y i e l d s an a r e a v a l u e but to determine the bonded a r e a , one must have a v a l u e f o r the unbonded s u r f a c e a r e a o f the pu l p f i b r e s . Methods such as s o l v e n t exchange, f r e e z e d r y i n g and spray d r y i n g o f d i l u t e s u s -p e n s i o n s on a c l e a n s u r f a c e o f a m a t e r i a l which w i l l not hydrogen bond have been t r i e d . S o l v e n t exchange and f r e e z e d r y i n g p r o b a b l y g i v e v a l u e s t h a t are too h i g h as these t e c h n i q u e s prevent the complete c l o s i n g of the pore s t r u c t u r e s o f the I n d i v i d u a l f i b r e s and thus the s u r f a c e a r e a o f the un-bended pulp i s h i g h by the amount of s u r f a c e i n the pores which -61-would have c o l l a p s e d on d r y i n g . Spray d r y i n g o f a d i l u t e s u s p e n s i o n , w h i l e not i d e a l , s h o u l d y i e l d r e a s o n a b l e e s t i m a t e s o f t h e unbonded a r e a . Of c o u r s e , i n h e r e n t i n the method o f p r e p a r i n g an unbonded m a t e r i a l i s the a s s u m p t i o n t h a t the e x t e r n a l s p e c i f i c s u r f a c e i s not a f f e c t e d by t h e s t r e s s e s o f r e s t r a i n e d d r y i n g t h a t o c c u r i n a paper s h e e t . A n o t h e r t e c h n i q u e o f d e t e r m i n i n g an "unbonded" s u r f a c e a r e a i s t o e x t r a p o l a t e t h e Young's modulus or t e n s i l e str'ength t o z e r o when p l o t t e d a g a i n s t the sample's s u r f a c e a r e a . T h i s method i s f r a u g h t w i t h p o s s i b l e f a u l t y a s s u m p t i o n s . L i g h t s c a t t e r i n g measurement t e c h n i q u e s have t h e r e s o l u t i o n p r o b l e m o f the p o l a r i z e d l i g h t as w e l l as r e q u i r i n g a c a l i b r a t i o n c urve t o c o n v e r t s p e c i f i c s c a t t e r i n g c o e f f i c i e n t s t o a r e a s . The d i r e c t c u r r e n t e l e c t r i c a l c o n d u c t i v i t y a l s o r e q u i r e s a c a l i b r a t i o n c u r v e . These c a l i b r a t i o n c u r v e s a r e u s u a l l y d e t e r m i n e d from gas a d s o r p t i o n d a t a . Thus, except f o r m i c r o s c o p i c t e c h n i q u e s , measurement of bonded a r e a s i s dependent on a gas a d s o r p t i o n measurement o f a r e a . -62-IV - BACKGROUND THEORY A - The B. E. T. Equation and Surface Area In 1938, Brunauer, Emmett and T e l l e r (91) proposed a method of measuring s p e c i f i c surface areas from vapour adsorption isotherms. This method has since become almost a standard f o r measuring surface areas of f i n e l y d i v i d e d m a t e r i a l s . The o r i g i n a l d e r i v a t i o n of the equation was based on a k i n e t i c approach t o ads o r p t i o n . By assuming the same model, a s t a -t i s t i c a l mechanical d e r i v a t i o n has been shown to produce the same equation (92). The B.E.T. Equation i n i t s most common working form i s : x ( p o - P) c - 1 \x c / \p^ (3) Thus when p/x(p Q-p) i s p l o t t e d against p/po> a s t r a i g h t l i n e should r e s u l t w i t h slope = ( c - l ) / x c and i n t e r c e p t = I/x c. m m Thus knowledge of the slope and i n t e r c e p t allows c a l c u l a t i o n of the monolayer volume, x^, and the value of the constant, c. Genera l l y the B.E.T. equation w i l l y i e l d a s t r a i g h t l i n e over the p a r t i a l pressure range of 0.05 - 0.30, however, there are cases i n which the B.E.T. p l o t begins to depart from l i n e a r i t y when the r e l a t i v e pressure exceeds 0.1 (93). The B.E.T. equation has been subjected to a number of c r i t i c i s m s . The model assumes the surface i s e n e r g e t i c a l l y uniform ( i . e . a l l a d s o r p t i o n s i t e s are e x a c t l y e q u i v a l e n t ) but there i s . e v i d e n c e (94-101) that the surfaces of most s o l i d s are hetrogeneous i n an e n e r g e t i c sense. The B.E.T. model n e g l e c t s l a t e r a l i n t e r a c t i o n s between m o l e c u l e s w i t h i n the adsorbed l a y e r ( 2 0 ) . Moreover, the n e g l e c t o f l a t e r a l i n t e r a c t i o n s i s a t v a r i a n c e w i t h t h e p o s t u l a t e t h a t the heat o f a d s o r p t i o n f o r the second and s u c c e e d i n g l a y e r s i s e q u a l t o the l a t e n t heat o f c o n d e n s a t i o n . I t has been q u e s t i o n e d (102, 103) i f a l l l a y e r s a f t e r the f i r s t s h o u l d be t r e a t e d as c o m p l e t e l y e q u i v a l e n t . B.E.T. e q u a t i o n t o an i s o t h e r m i s t h e amount of a d s o r b a t e r e q u i r e d t o c o v e r the s u r f a c e w i t h a monomolecular l a y e r . The s p e c i f i c s u r f a c e a r e a i s o b t a i n e d by m u l t i p l y i n g t h i s v a l u e by the m o l e c u l a r c r o s s - s e c t i o n a l a r e a . Thus one i s c o n f r o n t e d w i t h t h e dilemma: what i s the m o l e c u l a r c r o s s -s e c t i o n a l area? Emmett and Brunauer (104) c a l c u l a t e d the c r o s s - g e c t i o n a l a r e a o f the a d s o r b a t e m o l e c u l e s from the d e n s i t y o f t h e a d s o r b a t e i n the b u l k l i q u i d or s o l i d form by the e q u a t i o n : Where the v a l u e o f / the p a c k i n g f a c t o r , depends on the number o f n e a r e s t n e i g h b o u r s . The p a c k i n g f a c t o r v a l u e , 1.091, f o r t w e l v e n e a r e s t n e i g h b o u r s i n - t h e b u l k l i q u i d and s i x on the p l a n e , i s u s u a l l y used. Emmett and Brunauer c a l c u l a t e d a v a l u e o f 16.2 sq ft per n i t r o g e n m o l e c u l e and t h i s has become somewhat o f a s t a n d a r d v a l u e , w i t h the m o l e c u l a r The v a l u e x o b t a i n e d from the a p p l i c a t i o n o f the m A m (4) -64-c r o s s - s e c t i o n a l areas of other adsorbates adjusted to agree w i t h t h i s value f o r n i t r o g e n . I t has been suggested by A r i s t o v and K i s e l e v (105) that f o r some s o l i d s , the value of argon be used as a standard 2 w i t h a coverage of 13-7 ft per molecule and the values of n i t r o g e n and other adsorbates be adjusted a c c o r d i n g l y . The reasoning behind t h i s suggestion was that f o r adsorption on i o n i c or c a t i o n c o n t a i n i n g s u r f a c e s , there are a'dditional, probably mainly e l e c t r o s t a t i c , i n t e r a c t i o n s of the n i t r o g e n molecule quadrupoles with the e l e c t r i c f i e l d of the surfa c e . Argon molecules are not subjected to these a d d i t i o n a l i n t e r -a c t i o n s . L i v i n g s t o n (106) and Kodera and Onishi (107) suggested using values of 15.4 and 14.2 ft / molecule r e -s p e c t i v e l y as the area covered per n i t r o g e n molecule. Gregg and Sing (20) have w r i t t e n an extensive review of experimental work on the determination of surface area by the B.E.T. equation using a n i t r o g e n molecular c r o s s - s e c t i o n a l area of 16.2 ft . They concluded that the surface area of a sample as c a l c u l a t e d from the n i t r o g e n adsorption Isotherm u s u a l l y agrees to w i t h i n 20 percent and o f t e n l e s s w i t h surface areas c a l c u l a t e d from p a r t i c l e geometry. However, some problems do e x i s t , P i e r c e and Ewing (108) have obtained evidence that i n d i c a t e s the adsorption of n i t r o g e n on graphite i s l o c a l i z e d and covers four u n i t hexagons of grap h i t e s u r f a c e , thus having an e f f e c t i v e area of about 20 ft per molecule. Also the surface areas c a l c u l a t e d f o r microporous m a t e r i a l s are apparently i n considerable e r r o r . This w i l l be discussed i n s e c t i o n IV-E. A r i s t o v and K i s e l e v (105) found that other adsorbates d i d not -65-have the same value f o r molecular c r o s s - s e c t i o n a l area f o r a l l m a t e r i a l s i f the measured surface area was forced to agree w i t h the argon values. Their r e s u l t s are shown i n t a b l e 13. Using n i t r o g e n as a base, Gregg and Sing (20) and Davis et a l (109) found a s i m i l a r r e s u l t f o r other adsorbates. Table 13*: Approximate Molecular C r o s s - s e c t i o n a l Areas on Various M a t e r i a l s . Adsorbent A f o r v a r i o u s adsorbates, Kc —m N 2 at -195°c Ar at Benzene at -195°c 20°c G r a p h i t i z e d carbon blacks 16.2 Hydroxylated s i l i c a s 13-6 Dehydroxylated s i l i c a s 14.8 13.7 13.7 13.7 40 41 * Table 2 of reference (105) -66-B - Most Common Pore S i z e and Adsor b a t e M o l e c u l e S i z e The pore s i z e w i t h the l a r g e s t volume o f pores i s c a l l e d t h e most common pore s i z e . I n n i t r o g e n a d s o r p t i o n s t u d i e s on s o l v e n t exchange d r i e d c e l l u l o s e , t he most common pore s i z e i s found t o be about 1 9 ft r a d i u s i f a c y l i n d r i c a l pore shape i s assumed, o r 2 5 ft w a l l s e p a r a t i o n i f a p a r a l l e l s i d e d f i s s u r e pore shape i s assumed. F i g u r e 14 i s a s c a l e d rawing showing t h e s e two p o s s i b l e shapes o f pores and t h e r e l a t i v e s i z e o f t h e adsorbed n i t r o g e n m o l e c u l e s . The t h i c k -ness o f a monolayer i s shown . i f one assumes the hexagonal.; p a c k i n g model o f L i p p e n s , L i n s e n and de Boer ( 1 1 0 ) . A l s o shown i s the s t a t i s t i c a l t h i c k n e s s o f t h e adsorbed n i t r o g e n m o l e c u l e s when the pore has j u s t emptied and t h e system i s at e q u i l i b r i u m on a d e s o r p t i o n i s o t h e r m . The w a l l s o f the p o r e s , which are c e l l u l o s e m o l e c u l e s , are o f cour s e not f l a t and c o n t i n u o u s as i n d i c a t e d but are comprised o f atoms of a s i z e commensurate w i t h t h a t i n d i c a t e d f o r the n i t r o g e n m o l e c u l e s . T h i s f i g u r e e m p h a t i c a l l y shows the s i g n i f i c a n c e o f the problem o f assuming continuum b u l k l i q u i d p r o p e r t i e s i n pores o f t h i s magnitude where the dimensions o f the adsorbed mole^-c u l e s a r e o f s i m i l a r o r d e r o f magnitude as the pore d i m e n s i o n s . Some c o n f u s i o n as t o the meaning.of v a r i o u s terms has been found. Throughout t h i s work, maan or median pore s i z e i m p l i e s the pore s i z e at which h a l f the pore volume i s c o n t a i n e d i n s m a l l e r pores and h a l f t h e - p o r e volume i n l a r g e r p o r e s . The most common pore s i z e i s the pore s i z e w i t h the l a r g e s t volume o f p o r e s . -67-FI6URE 14. RELATIVE SIZES OF MOST COMMON PORE SIZE AND ADSORBED NITROGEN MOLECULES. LIMIT OF STATISTICAL MONOLAYER THICKNESS I i \ \ PARALLEL SIDED FISSURE SHAPED PORE 25 A* WALL SEPARATION LIMIT OF NUMBER OF STATISTICAL MULTILAYER COVERAGE AT EQUILIBRIUM RELATIVE PRESSURE. \ CYLINDRICAL PORE 19 A* RADIUS. I r l i f f B U L K L IQUID P R O P E R T I E S A S S U M E D -68-C - D e t e r m i n i n g Pore S i z e by the K e l v i n E q u a t i o n The K e l v i n e q u a t i o n , which i s t h e b a s i s o f many o f the methods o f c a l c u l a t i n g pore s i z e d i s t r i b u t i o n s from i s o -therm d a t a (46-48, 111-114), was d e r i v e d i n a paper by W'.T. Thompson ( L o r d K e l v i n ) p u b l i s h e d i n 1871 ( 1 1 5 ) . The K e l v i n e q u a t i o n as p r e s e n t l y used i s : dv _ V Y , / c\ — = 1 c o s f (5) dS RT l n ( p / p ) The e q u a t i o n d e s c r i b e s t h e e q u i l i b r i u m c o n d i t i o n between t h e vapour p r e s s u r e o f an a d s o r b a t e and t h e l a r g e s t s i z e o f pore which w i l l be f i l l e d w i t h l i q u i d a d s o r b a t e . I n o r d e r t o use the e q u a t i o n , i t i s n e c e s s a r y t o a s s i g n v a l u e s t o the s u r f a c e t e n s i o n , Y , the a n g l e o f c o n t a c t , (j> , and molar volume o f t h e a d s o r b a t e m o l e c u l e s , V ( o r t h e d e n s i t y , ). The u s u a l method o f a s s i g n i n g t h e s e v a l u e s i s t o assume t h a t the a d s o r b a t e p e r f e c t l y wets the adsorbent s u r f a c e (i.e.cf>= 0) and-t h a t the b u l k l i q u i d v a l u e s o f s u r f a c e t e n s i o n and d e n s i t y are a p p l i c a b l e . One must a l s o assume a pore shape t o o b t a i n a dimension, o f t h e l i m i t i n g pore s i z e . C y l i n d r i c a l pores are u s u a l l y assumed. The p h y s i c a l pore s i z e i s l a r g e r t h a n the K e l v i n pore s i z e by v i r t u e o f the l a y e r s o f a d s o r b a t e adsorbed on the s u r f a c e by the m u l t i l a y e r a d s o r p t i o n mechanism. I t i s i n c a l c u l a t i n g t h i s t h i c k n e s s t h a t most o f t h e methods (46-48, 111-114) d i f f e r . The use o f a K e l v i n e q u a t i o n method f o r d e t e r -m i n i n g t h e pore s i z e d i s t r i b u t i o n o f an adso r b e n t from a n : -69-i s o t h e r m has been s u b j e c t e d t o t h r e e main c r i t i c i s m s : (a) The v a l i d i t y o f the K e l v i n e q u a t i o n i t s e l f . (b) The assessment o f the t h i c k n e s s o f the r e s i d u a l adsorbed f i l m . (c) The assumption o f t h e shape o f the pores F o r the convex s u r f a c e o f d r o p l e t s the K e l v i n e q u a t i o n has been v e r i f i e d f o r r a d i i o f c u r v a t u r e o f s e v e r a l m icrons f o r water (116) d i b u t y l p h t h a l a t e (117) and mercury (118) . V e r i f i c a t i o n was a l s o o b t a i n e d f o r d r o p l e t s l e s s t h a n a m i c r o n I n d i a m e t e r f o r d i o c t y l p h t h a l a t e and o l e i c a c i d (119) . However, f o r the concave s u r f a c e o f a l i q u i d meniscus i n a c a p i l l a r y o f the o r d e r o f one m i c r o n d i a m e t e r , the ex-p e r i m e n t a l r e s u l t s a r e c o n s i d e r a b l y d i f f e r e n t from t h e v a l u e s c a l c u l a t e d by the K e l v i n e q u a t i o n . C o n s i d e r i n g t h e e x p e r i -m ental r e s u l t s o f o t h e r s (120-122) as w e l l as t h e i r own exp e r i m e n t s w i t h p o l a r and n o n - p o l a r m a t e r i a l s , Folman and Sh e r e s h e f s k y (123) c o n c l u d e d : "The r e s u l t s o f t h e s e measurements show t h a t the K e l v i n e q u a t i o n cannot be a p p l i e d i n e s t i m a t i n g vapour p r e s s u r e l o w e r i n g over concave s u r f a c e s i n m i c r o s c o p i c c a p i l l a r i e s . Nor can i t be a p p l i e d i n e s t i m a t i n g pore r a d i i at g i v e n vapour p r e s s u r e s as i t i s done i n a d s o r p t i o n a n a l y s i s . The o b s e r v e d l o w e r i n g i s many tim e s g r e a t e r t h a n the v a l u e c a l c u l a t e d w i t h t h i s e q u a t i o n . Moreover, the e f f e c t d i f f e r s i n magnitude w i t h the n a t u r e o f the l i q u i d . The l o w e r i n g f o r i s o p r o p y l a l c o h o l was found t o be much g r e a t e r t h a n f o r t o l u e n e , and the r e s u l t s f o r water r e -p o r t e d i n the p r e c e d i n g paper (122) show t h a t the e f f e c t f o r t h e l a t t e r i s s t i l l g r e a t e r . T h i s e f f e c t seems t o change w i t h the p o l a r i t y o f t h e l i q u i d , and i n c r e a s e s w i t h d i p o l e moment o f t h e m o l e c u l e . " - 7 0 -E x p e r i m e n t a l d a t a f o r c a p i l l a r i e s o f the o r d e r o f 1-10 m i c r o n s d i a m e t e r show no s i g n i f i c a n t changes i n s u r f a c e t e n s i o n (124) or d e n s i t y ( 1 2 5 , 1 2 6 ) . However, i n r e c e n t work, F e d y a k i n ( 127 ) found th e s u r f a c e t e n s i o n o f l i q u i d s (water and benzene) measured i n c a p i l l a r y tubes o f r a d i u s down t o 200 ft ( 0 . 0 2 m i c r o n s ) d i a m e t e r was dependent on the r a d i u s o f the t u b e . A l s o , t h e o r e t i c a l c o n s i d e r a t i o n s by Tolman ( 128 ) and H i l l ( 129 ) r e q u i r e t h a t the e f f e c t o f c u r v a t u r e on s u r f a c e t e n s i o n be s l i g h t i n c a p i l l a r i e s o f 1 m i c r o n but become a p p r e c i a b l e f o r r a d i i o f 100 ft and i n c r e a s e w i t h d e c r e a s i n g s i z e . D e r y a g i n (38) r e c e n t l y has shown the e x i s t e n c e o f water i n q u a r t z c a p i l l a r i e s o f 2r-20. m i c r o n s d i a m e t e r which has a d e n s i t y o f 1 . 3 g./ml. Thus, the v a l i d i t y o f t h e K e l v i n e q u a t i o n i n p o r e s o f the o r d e r o f a few angstroms i s v e r y d o u b t f u l even f o r n o n - p o l a r a d s o r b a t e s . To show the p o s s i b l e e f f e c t o f e r r o r s i n the p h y s i c a l p r o p e r t y p a r a m e t e r s , th e c u m u l a t i v e pore volume d i s -t r i b u t i o n s were c a l c u l a t e d , u s i n g the P i e r c e method (48) from a s o l v e n t exchange d r i e d wood p u l p n i t r o g e n d e s o r p t i o n i s o t h e r m . The K e l v i n e q u a t i o n was r e a r r a n g e d t o the form: — 2M Y .,. - 4.14 K ,c\ T = r. = - 1 coscj) = (6) K ; RTp l n ( p / p o ) l n ( p / p Q ) The v a l u e s o f K were v a r i e d from 0 . 5 t o 2 . 0 i n a manner s i m i l a r t o t h a t used by Spencer and Fereday ( 1 3 0 ) . The r e s u l t s o f t h e s e c a l c u l a t i o n s a r e shown i n f i g u r e s 15 and 16 which show t o what e x t e n t t h e pore volume d i s t r i b u t i o n depends ro o o CO j> Oi 2 O O ro 03 ro H ro o ro > o CO CO c ay ro = 8 8 CUMULATIVE PORE VOLUME 8 (ml* N 2 (8.T.P.)) 8 • ro 6 o z PO a) 30 > ro r~ r < ro o r* r c CO o ro ro o o CO -n H CO 3) CO CD c C 30' H ro O Z z o o ro r ro 5> ro o — - 1 « z o •o z -< CO o > r 2 30 X> ro H ro a> CO -73-on the values of the p h y s i c a l p r o p e r t i e s of the adsorbate. The number of monomolecular l a y e r s on the surface i s determined from isotherms on nonporous s o l i d s of e s s e n t i a l l y the same p r o p e r t i e s (on a molecular l e v e l - see s e c t i o n VI-G). This estimate of the number of molecular l a y e r s w i l l p o s s i b l y be i n e r r o r as o v e r l a p p i n g p o t e n t i a l f o r c e s from the adjacent pore w a l l s may increase the ad-s o r p t i o n of the adsorbate over that p r e d i c t e d from a non-porous ads o r p t i o n isotherm (105). Even wi t h a p r e d i c t e d number of monomolecular l a y e r s adsorbed onto the pore w a l l s , the t h i c k n e s s of each monolayer i s not known. A search of the l i t e r a t u r e has revealed c o n s i d e r a t i o n s only f o r the t h i c k n e s s of a monolayer of n i t r o g e n . Lippens et a l (110) assumed a hexagonal packing and a normal bulk d e n s i t y f o r the condensed n i t r o g e n and a r r i v e d at a t h i c k n e s s of 3.54 ft per monolayer. S h u l l (47) determined a t h i c k n e s s of 4.3 ft per monolayer. He assumed a v e r t i c a l s t a c k i n g r a t h e r than the c l o s e r hexagonal packing. Both workers assumed a l l monolayers are of the same estimated t h i c k n e s s . Figure 17 shows the d i f f e r e n c e i n the cumulative pore volume d i s -t r i b u t i o n w i t h the two models. The value assigned to the t h i c k n e s s of a monolayer of adsorbed argon, 3-28 ft, was determined using the Lippens et a l model and equations w i t h the e x t r a p o l a t e d bulk l i q u i d argon d e n s i t y assumed to be 1.452 g./ml. The pore volume d i s t r i b u t i o n i s s e n s i t i v e to the geometry assumed f o r the pore. For example, i n c y l i n d r i c a l pores r ^ i n equation 6 i s the c y l i n d e r r a d i u s , but f o r 1 I 1 8 0 6 0 - 1 1 1 1 1 i i i i i i 20 25 30 40 50 60 70 80 90 100 DISTANCE BETWEEN WALLS O F FISSURES (A*) - 7 5 -p a r a l l e l sided f i s s u r e s r, i s x, the pore width. r, k k f o r other geometries has other values (page 139 reference 2 0 ) . Considering the probable i r r e g u l a r i t y of the shape of pores occurring i n an adsorbent, the choice of the form of the K e l v i n equation must depend on other i n f o r m a t i o n than on the s t r u c t u r e of the m a t e r i a l i f ' i t i s to have much s i g -n i f i c a n c e . In s p i t e of the serious drawbacks to the K e l v i n equation, i t remains the only p r a c t i c a l means of o b t a i n i n g q u a n t i t a t i v e i n f o r m a t i o n on pore s i z e d i s t r i b u t i o n i n the range of 15-150 ft. D - Dubinin Pore S i z e C l a s s i f i c a t i o n s Dubinin (131-133) as a r e s u l t of h i s work w i t h porous carbons, grouped pores i n t o three c l a s s i f i c a t i o n s : macropores, Intermediate or t r a n s i t i o n a l pores and micro-pores. The s i z e range, adsorption c h a r a c t e r i s t i c s and methods of examination of each pore c l a s s are b r i e f l y d i s -cussed below. 1. Macropores: The e f f e c t i v e r a d i i of the l a r g e s t v a r i e t y of adsorbent pores, macropores, exceed 1000-2000 ft. Under ordi n a r y c o n d i t i o n s of adso r p t i o n experiments the macropore volume cannot be f i l l e d as a r e s u l t of c a p i l l a r y condensation of vapours because of the d i f f i c u l t y of a c h i e v i n g e q u i l i b r i u m f o r r e l a t i v e pressures near u n i t y and because the adso r p t i o n pro-cess has an extremely slow r a t e under these c o n d i t i o n s . Thus, macropores play the part of t r a n s p o r t pores and make the i n t e r n a l p a r ts of grains or p e l l e t s of adsorbents e a s i l y a c c e s s i b l e f o r the adsorbed molecules. Information concerning the volume d i s -t r i b u t i o n of the macropores can be obtained by measuring the volume of mercury which can be forced i n t o the pores under various pressures. Intermediate or T r a n s i t i o n a l Pores The e f f e c t i v e r a d i i of intermediate or t r a n s -i t i o n a l pores are much l a r g e r than the s i z e of the molecules adsorbed. The surface of an intermediate pore has monomolecular l a y e r s of adsorbate formed on i t during the adsorption process. The f i l l i n g of intermediate pores by the c a p i l l a r y condensation mechanism takes place w i t h i n the range of r e l a t i v e pressures e a s i l y r e a l i z a b l e i n experiments. Some-what c o n v e n t i o n a l l y we can consider that the e f f e c t i v e r a d i i of intermediate pores l i e between 15-20 ft and 1000-2000 ft. The lower boundary of the e f f e c t i v e r a d i i corresponds to the l i m i t of a p p l i c a b i l i t y of the K e l v i n equation, as shown by Dubinin et a l (134, 135) on the ba s i s of a thermo-dynamic a n a l y s i s of experimental data on ads o r p t i o n and c a p i l l a r y condensation of vapours. Dubinin (131) discusses means of examining the d i s t r i b u t i o n and volume of these intermediate or t r a n s i t i o n a l pores. The method of f o r c i n g mercury i n t o pores under pressure can be used, however -77-adsorption methods are u s u a l l y u t i l i z e d . In the region of c a p i l l a r y condensation the s o r p t i o n and desorption branches do not c o i n c i d e and form a c h a r a c t e r i s t i c h y s t e r e s i s loop. I t i s i n the t r a n s i t i o n a l pores that c a p i l l a r y conden-s a t i o n of adsorbate vapour takes place. The space between adsorbed f i l m s i n these pores i s la r g e enough, compared with the dimensions of an adsorbate molecule, f o r the idea of a concave l i q u i d meniscus i n such pores to have p h y s i c a l s i g n i f i c a n c e . The s p e c i f i c surface area of t r a n s i t i o n a l pores can be assessed from the surface area of the adsorbed f i l m covering the pore w a l l s at the beginning of c a p i l l a r y condensation. Completion of the c a p i l l a r y condensation process, when the r e l a t i v e pressure becomes equal to u n i t y , leads to the f i l l i n g of the e n t i r e volume of t r a n s i t i o n a l pores with condensed vapour and consequently to the disappearance of the surface of the adsorbed f i l m s . As the t r a n s i t i o n a l pores are l a r g e r by at l e a s t one order of magnitude than adsorbed molecules of vapour, the thickness of the multimolecular f i l m s . o n the s u r f a c e , two or three monolayers t h i c k , i s not s u f f i c e n t to d i m i n i s h the diameter s e r i o u s l y . There can, t h e r e f o r e , be s c a r c e l y any doubt as to the r e a l i t y of the process of c a p i l l a r y condensation of vapour i n such pores, s t i l l so l a r g e i n comparison to molecular dimensions. -78-3 - M i c r o p o r e s F o r t h e s m a l l e s t v a r i e t y o f a d s o r b e n t p o r e s , m i c r o p o r e s , t h e e f f e c t i v e r a d i i a r e w i t h i n t h e r a n g e f r o m 5-6 ft t o 13-14 ft, a s shown by t h e s m a l l a n g l e X - r a y s c a t t e r i n g m e t h o d (136). W i t h r e g a r d t o t h e i r s i z e s , m i c r o p o r e s a r e o f s i m i l a r s i z e t o t h e m o l e c u l e s a d s o r b e d . F o r a d s o r b e n t s w i t h s u c h s m a l l p o r e s t h e c u s t o -mary c o n c e p t s o f l a y e r - b y - l a y e r c o v e r a g e a n d o f a m i c r o p o r e s u r f a c e a r e a l o s e t h e i r p h y s i c a l s i g n i -f i c a n c e . As f a r a s i t s m e c h a n i s m i s c o n c e r n e d , t h e phenomenon o f a d s o r p t i o n i n m i c r o p o r e s d i f f e r s r a d i c a l l y f r o m a d s o r p t i o n o c c u r r i n g on t h e s u r f a c e o f i n t e r m e d i a t e p o r e s o r m a c r o p o r e s a n d i n t h e l i m i t i n g c a s e , on t h e s u r f a c e o f n o n p o r o u s a d s o r b e n t s . A d s o r p t i o n on m i c r o p o r o u s a d s o r b e n t s i n v o l v e s n o t a s u c c e s s i v e f o r m a t i o n o f a d s o r p t i o n l a y e r s on t h e s u r f a c e o f t h e m i c r o p o r e s b u t t h e f i l l i n g o f t h e i r a d s o r p t i o n s p a c e . The c o n c e p t o f a s u r f a c e a r e a o f m i c r o p o r o u s a d s o r b e n t s l o s e s i t s p h y s i c a l s i g n i f i c a n c e . A c h a r a c t e r i s t i c f e a t u r e o f a d s o r p t i o n on m i c r o p o r o u s a d s o r b e n t s i s a s u b s t a n t i a l i n c r e a s e i n t h e a d s o r p t i o n e n e r g y a n d c o n s e q u e n t l y , t h e a d s o r p -t i o n p o t e n t i a l s i n m i c r o p o r e s a s c o m p a r e d t o t h e c o r r e s p o n d i n g v a l u e s f o r l a r g e p o r e d i n t e r m e d i a t e p o r e d J o r n o n p o r o u s a d s o r b e n t s o f a s i m i l a r c h e m i c a l n a t u r e . The c u r v e s o f d i f f e r e n t i a l h e a t s -79-o f a d s o r p t i o n o f the a d s o r b a t e on a m i c r o p o r o u s and non-porous a d s o r b e n t s h o u l d show a s i g n i f i c a n t i n c r e a s e i n a d s o r p t i o n e n e r g i e s f o r the m i c r o -porous case over the non-porous ca s e . An i n c r e a s e i n a d s o r p t i o n energy i n m i c r o p o r e s l e a d s t o a c o n s i d e r a b l e i n c r e a s e i n the v a l u e o f vapor a d s o r p t i o n i n t h e r e g i o n o f low e q u i l i b r i u m p r e s s u r e s . T a b l e 14 l i s t s r e l a t i v e a d s o r p t i o n v a l u e s o f benzene at 20°C f o r nonporous c a r b o n b l a c k Spheron-6 w i t h a s u r f a c e a r e a o f 77 sq.m./g. p r e v i o u s l y t h e r m a l l y t r e a t e d at 950°C, and f o r two specimens o f a c t i v e carbons AC-1 and AC-2 a c t i v a t e d at 950°C. and p o s s e s s i n g d i f f e r e n t m i c r o p o r o u s s t r u c t u r e s . The amounts adsorbed f o r each a d s o r b e n t at an e q u i l i b r i u m r e l a t i v e p r e s s u r e p/p Q=0.175 are adopted as a r b i t r a r y u n i t s . F o r car b o n b l a c k t h i s p r e s s u r e a p p r o x i m a t e l y c o r r e s p o n d s t o t h e f o r m a t i o n o f a complete monolayer, whereas f o r a c t i v e c a r b o n s , i t c o r r e s p o n d s t o the p r a c t i c a l c o m p l e t i o n o f t h e f i l l i n g o f m i c r o p o r e s as a r e s u l t o f a d s o r p t i o n . The e x p e r i m e n t a l d a t a o f t a b l e 14 i l l u s t r a t e how g r e a t l y the v a l u e s o f vapor a d s o r p t i o n I n c r e a s e I n p a s s i n g from nonporous ( o r i n t e r m e d i a t e p ored ) t o m i c r o p o r o u s carbonaceous a d s o r b e n t s , p a r t i c u l a r l y f o r AC-2 w i t h s m a l l e r m i c r o p o r e s . * v a l u e o f a d s o r p t i o n = amount o f a d s o r p t i o n T a b l e 14*: R e l a t i v e A d s o r p t i o n V a l u e s f o r Benzene a t 20°0 on Carbon B l a c k and A c t i v e Carbons Carbon B l a c k A c t i v e Carbons 0 AC-1 AC-2 1 v 1 0 " 5 0.02 0.12 0.44 1 x 1 0 " 4 0 . 0 6 0.16 0.57 1 x 1 0 " 3 0.14 0.46 0.73 1 x 1 0 " 2 0.33 0.71 0-87 1 x 1 0 " 1 0.81 0.92 0.96 0.175 1.00 1.00 1.00 The p h y s i c a l p r o p e r t i e s o f m i c r o p o r e s a r e b e s t d e t e r m i n e d by low a n g l e X-ray s c a t t e r i n g and by gas a d s o r p t i o n i s o t h e r m s w h i c h a r e a n a l y s e d u s i n g t h e t h e o r i e s d e v e l o p e d by D u b i n i n (132,133, 137). E - The S p e c i a l Problem o f M i c r o p o r e s I f a s o l i d c o n t a i n s m i c r o p o r e s ( i . e . p o r e s which have a w i d t h o f up t o a few m o l e c u l a r d i a m e t e r s ) i t s ad-s o r p t i v e b e h a v i o r w i l l be o t h e r t h a n t h a t o f non-porous o r macroporous s o l i d s . I n p a r t i c u l a r , t h e p o t e n t i a l f i e l d s from o p p o s i t e w a l l s o f t h e pore w i l l o v e r l a p so t h a t t h e * From R e f e r e n c e (132) - 8 1 -a t t r a c t i v e f o r c e s a c t i n g on a d s o r b a t e m o l e c u l e s w i l l be i n c r e a s e d i n c o m p a r i s o n t o t h o s e p r e s e n t on an o p e n s u r -f a c e . The a d s o r p t i o n i s o t h e r m w i l l a c c o r d i n g l y be d i s -t o r t e d i n t h e d i r e c t i o n o f a n i n c r e a s e d a d s o r p t i o n . T h i s phenomenon i s e v i d e n c e d by i n c r e a s e d a d s o r p t i o n e n e r g y a n d i n c r e a s e d t o t a l a d s o r p t i o n as m e a s u r e d by D u b i n i n ( 132) and d i s c u s s e d a b o v e i n s e c t i o n I V - D - 3 D u b i n i n ( 1 3 2 , 1 3 5 , 1 3 8 ) s t u d i e d t h e a d s o r p t i o n o f w a t e r a n d n i t r o g e n o n t o v e r y c a r e f u l l y p r e p a r e d s a m p l e s o f t h e a l u m i n o - s i l i c a t e f r a m e w o r k o f d e h y d r a t e d c r y s t a l s o f s y n t h e t i c z e o l i t e s . . The s h a p e s a n d d i m e n s i o n s o f t h e c a v i t i e s o r p o r e s i n t h e d e h y d r a t e d c r y s t a l s were d e t e r -m i n e d by X - r a y d i f f r a c t i o n m e a s u r e m e n t s . T h i s a l l o w e d a n e s t i m a t e o f t h e s p e c i f i c s u r f a c e o f t h e s a m p l e s . The l i q u i d v o l u m e o f g a s r e q u i r e d t o f o r m a m o n o l a y e r a s c a l c u l a t e d by t h e B.E.T. method f o r t h i s c o m p u t e d s u r f a c e a r e a was f o u n d t o be l a r g e r t h a n t h e p o r e v o l u m e a v a i l a b l e as m e a s u r e d by X - r a y d i f f r a c t i o n . H o w e v e r , t h e a d s o r p t i o n i s o t h e r m s d i d y i e l d g o o d , l i n e a r B.E.T. p l o t s . I n l a r g e r m i c r o p o r e s , where i t i s p h y s i c a l l y p o s s i b l e t o a d s o r b two o r more l a y e r s , t h e i n c r e a s e d h e a t o f a d s o r p t i o n I n t h e s e c o n d and p o s s i b l y h i g h e r l a y e r s o b s c u r e s t h e c h a n g e s i n a d s o r p t i o n b e t w e e n t h e f i r s t a n d h i g h e r l a y e r s ( 1 3 9 ) . T h u s , t h e r e w i l l be no m o n o l a y e r p o i n t on t h e i s o t h e r m a n d e v e n a l o n g t h e b r a n c h o f t h e i s o t h e r m n o r m a l l y u s e d f o r B.E.T. a n a l y s e s , c o m p l e t e f i l l i n g o f t h e p o r e s w i t h a d s o r b a t e m o l e c u l e s w i l l be o c c u r r i n g . I n c a s e s where t h i s i s s o , t h e c l a s s i c a l m e t h o d s o f c a l c u l a t i n g t h e m o n o l a y e r c a p a c i t y -82-w i l l , o f c o u r s e , b reak down. Some e v i d e n c e f o r t h i s break down o f c a l c u l a t i o n a l methods has been o b t a i n e d (140, 141); t h i s i s d i s c u s s e d by Gregg and S i n g ( 2 0 ) . The most d r a m a t i c p i e c e o f e v i d e n c e i s a p a r t i c u l a r s a r a n c h a r c o a l (140) w i t h a s p e c i f i c s u r f a c e o f 3130 sq.m./g. ( c a l c u l a t e d from an i s o t h e r m ) , however, as each carbon atom o f g r a p h i t e o c c u p i e s an a r e a o f 7 sq. ft, n i n e - t e n t h s o f a l l c a r b o n atoms I n the sample would have t o be a c c e s s i b l e t o the gas,' a phenomenon not p r o b a b l e i n view o f the p h y s i c a l s t r e n g t h o f the sample. The q u e s t i o n o f the p h y s i c a l b a s i s o f t h e lower r e l a t i v e p r e s s u r e l i m i t (and hence the pore s i z e ) down t o which i t i s p o s s i b l e t o use the K e l v i n e q u a t i o n based methods of c a l c u l a t i n g pore volume d i s t r i b u t i o n I s o f f undamental i m p o r t a n c e when one i s s t u d y i n g v e r y s m a l l p o r e s . T h i s l o w e r l i m i t o f a p p l i c a b i l i t y o f t h e K e l v i n e q u a t i o n i s d e t e r m i n e d by two c i r c u m s t a n c e s . The r e q u i r e -ment t h a t a concave l i q u i d meniscus be p r e s e n t i n the. space between th e a d s o r b a t e l a y e r s on the pore w a l l s , and t h a t t h e r e s h o u l d be no p o s s i b i l i t y o f volume f i l l i n g o f t h e r e -l a t i v e l y f i n e p o r e s by c o a l e s c e n c e o f the a d s o r p t i o n l a y e r s on o p p o s i t e w a l l s o f t h e pores as a r e s u l t o f an i n c r e a s e i n the a d s o r p t i o n p o t e n t i a l s due t o the o v e r l a p from a d j a c e n t s u r f a c e s . The i d e a o f t h e concave l i q u i d meniscus l o s e s i t s p h y s i c a l s i g n i f i c a n c e f o r f i n e p o r e s i n which the space be-tween the a d s o r p t i o n l a y e r s i s o n l y o f t h e o r d e r o f t h e t h i c k -ness of a few m o l e c u l e s . I n a c t u a l f a c t , the i n c r e a s e i n the adsorption p o t e n t i a l s i n f i n e pores leads to a sub-s t a n t i a l increase i n the amount of adsorption i n comparison wi t h that found f o r nonporous adsorbents. As a r e s u l t , the f i n e s t pores are f i l l e d w ith a form of l i q u e f i e d vapour caused by the coalescence of the adsorption l a y e r s during the primary adsorption process. In pores of somewhat l a r g e r s i z e s the overlapping adsorption p o t e n t i a l f i e l d s w i l l lead to s i g n i f i c a n t d e v i a t i o n s from the K e l v i n equation. F - The Dubinin Theory of Adsorption on Microporous S o l i d s (131,133,142) theory of adsorption of gases and vapours by microporous adsorbents represented an extension of Polanyi's p o t e n t i a l theory of adsorption (143,144). According to Polanyi's treatment, the "adsorption space" i n the v i c i n i t y of a s o l i d surface i s c h a r a c t e r i z e d by a s e r i e s of e q u i p o t e n t i a l s u r f a c e s , ( i . e . surfaces of the same adsorption p o t e n t i a l ) . The adsorption p o t e n t i a l , e,at the l i q u i d -vapour i n t e r f a c e i s given by: and since by hypothesis the adsorbate i s i n l i q u i d form, the volume occupied by the adsorbed vapour can be expressed as : In the i n i t i a l stages of development, Dubinin's e (7) w x (8) P -84-As both W and e can be c a l c u l a t e d from an experimental isotherm, i t i s p o s s i b l e to. evaluate the equation of the c h a r a c t e r i s t i c curve. W = f ( e ) (9) P o l a n y i made no attempt to derive an expression f o r the adsorption isotherm from the p o t e n t i a l theory. Dubinin and co-workers ( 1 3 3 , 142) have derived such an ex-p r e s s i o n using the f o l l o w i n g arguments. The adsorption p o t e n t i a l , which i s due to d i s p e r s i o n and p o l a r forces between the adsorbent and adsorbate molecules i s I n -dependent of temperature but v a r i e s according to the nature of the adsorbate as w e l l as the adsorbent. However, both the- d i s p e r s i o n force and the p o l a r force are f u n c t i o n s of the p o l a r i z a b i l i t y of the adsorbed molecule. Thus, f o r two d i f f e r e n t adsorbates f i l l i n g the same volume of adsorption space, W, on a given adsorbent, the adsorption p o t e n t i a l of one adsorbate d i v i d e d by the adsorption p o t e n t i a l of the other w i l l be a constant independent of the adsorption space f i l l e d . This constant r a t i o of ad-s o r p t i o n p o t e n t i a l s i s termed the a f f i n i t y c o e f f i c i e n t , 6 , by Dubinin. I f a p a r t i c u l a r adsorbate i s taken as an a r b i t r a r y standard, by combining the c h a r a c t e r i s t i c curve (equation 9) with the a f f i n i t y c o e f f i c i e n t , a general expression f o r the c h a r a c t e r i s t i c curve i s obtained. -85-w = 0 \0 / (10) In t h i s case, e 0^- s the adsorption p o t e n t i a l of the standard adsorbate. Dubinin and h i s co-workers assumed that the volume of the adsorption space could be expressed as a Gaussian f u n c t i o n of the corresponding adsorption p o t e n t i a l . Thus the form of the general c h a r a c t e r i s t i c curve i s changed t o : W = V . e mic -k (e_\ W (11) Where V . i s the t o t a l microporous volume and k i s the con-mic ^ stant c h a r a c t e r i s i n g the pore s i z e d i s t r i b u t i o n . By s u b s t i t u t i n g equation (7) and (8) f o r W and e , and r e a r r a n g i n g , equation (11) becomes an expression f o r the adsorption. x = pV . expHr RT In — mlc U2i U / / (12) Taking the logarithm of equation (12), y i e l d s the working Dubinin equation. l o g 1 0 x = l o g 1 0 ( V m . c p ) - K 2 ( l o g 1 0 / ^ (13) - 8 6 -where: K = 2.303^-(RT) 2 (14) B 2 Thus a p l o t o f l o g 1 0 ( x ) vs. I l o g 1 0 | — should y i e l d a s t r a i g h t l i n e of slope D and i n t e r c e p t loe, r t(V . p). ^ &10 mic ' Dubinin (133,139) has found equation (13) to apply over the range of r e l a t i v e pressures 1x10 to 0.2 f o r a number of adsorbates i n c l u d i n g n i t r o g e n i n those cases where the adsorbent i s t r u l y microporous. Experimental adsorption data can be s u b s t i t u t e d d i r e c t l y i n t o equation (13) only i f the adsorbent i s h i g h l y microporous with weakly developed t r a n s i t i o n a l (or i n t e r -mediate) p o r o s i t y . Dubinin (133) stated that i f the s p e c i f i c surface area of the t r a n s i t i o n a l pores, , appreciably ex-ceeds 50 sq.m./g., the experimental values of a d s o r p t i o n , : f o r each r e l a t i v e pressure, p/p Q should be c o r r e c t e d f o r adsorp-t i o n on the surface of the t r a n s i t i o n a l pores: x = x - a S, (15) e t where a i s the value of vapour adsorption f o r a u n i t surface of the nonporous adsorbent, thus a i s a f u n c t i o n of r e l a t i v e pressure. The i n t e r c e p t of a Dubinin p l o t , l o g n n ( V . p), ^ 5 °10 mic ' represents the number of molecules r e q u i r e d to f i l l the micro-porous volume, thus, the equation i s free of the assumption that the bulk density of the l i q u i d adsorbate i s a p p l i c a b l e i n -87-the micropores. However, some value must be assigned to p i f an estimate of the microporous volume i s to be ob-Theory to c e l l u l o s e apparently are: a) The assumption that a Gaussian d i s t r i b u t i o n of the corresponding a d s o r p t i o n p o t e n t i a l would describe the micropore volume d i s t r i b u t i o n when apparently the pore s i z e d i s t r i b u t i o n i s of a wide range, i n c l u d i n g the micro- and t r a n s i t i o n a l - pore s i z e s . b) The theory assumes bulk f i l l i n g of the micropores but l a y e r by l a y e r f i l l i n g of the t r a n s i t i o n a l pores, w i t h no allowances f o r p o s s i b l e s t e r i c hinderance i n bulk f i l l i n g of micropores ( i . e . l e s s volume of l a r g e adsorbate molecules than small adsorbate molecules w i l l f i t i n t o very small pores). G - The Kaganer Method f o r Determination of the Surface Area Kaganer (145, 146) modified the Dubinin treatment to o b t a i n a method f o r the c a l c u l a t i o n of s p e c i f i c s urface. He assumed that the d i s t r i b u t i o n of ads o r p t i o n p o t e n t i a l over the s i t e s on the surface i s Gaussian i n type. Dubinin assumed that the volume of the adsorption space may be ex-pressed as a Gaussian f u n c t i o n of the corresponding adsorp-t i o n p o t e n t i a l . The Kaganer working equation i s : t a i n e d . The weaknesses of the a p p l i c a t i o n of the Dubinin (16) - 8 8 -E q u a t i o n (3.6) i s I d e n t i c a l i n form w i t h D u b i n i n ' s e q u a t i o n ( e q u a t i o n 13) and a ' p l o t o f l o g 1 Q x a g a i n s t l o g ^ Pp \ P~ s h o u l d a g a i n g i v e a s t r a i g h t l i n e w i t h the i n t e r c e p t on t h e o r d i n a t e a x i s (where p - p ) now e q u a l t o t h e l o g a r i t h m o f the monolayer c a p a c i t y r a t h e r t h a n t o t h e l o g a r i t h m o f the pore volume. Kaganer ( 1 4 5 , 146) used i s o t h e r m s o f a d s o r b a t e s . such as n i t r o g e n , argon and k r y p t o n on a d s o r b e n t s such as • s i l i c a g e l s , c h a r c o a l s and a l u m i n a s t o compare th e v a l u e s o f x o b t a i n e d from e q u a t i o n (16) t o the v a l u e s o f x ob-m . m t a i n e d from the B.E.T. e q u a t i o n . He found agreement o f I 3 p e r c e n t between the v a l u e s . However, o t h e r workers ( 1 4 7 , 148) have t e s t e d the Kaganer e q u a t i o n by m e a s u r i n g the a d s o r p t i o n o f n i t r o g e n at - 195 °K w i t h p y r e x g l a s s of known g e o m e t r i c a l a r e a as a d s o r b e n t . These workers found a wide d i s c r e p a n c y i n the measured s u r f a c e a r e a s a l t h o u g h the d a t a they c o n s i d e r e d b e s t agreed q u i t e w e l l . Thus l i k e the D u b i n i n method, the Kaganer method i s c e r t a i n l y worthy of f u r t h e r s t u d y a l t h o u g h a t p r e s e n t the method must be r e g a r d e d as e s s e n t i a l l y . " ' e m p i r i c a l . B o t h the Kaganer e q u a t i o n ( e q u a t i o n 1 6 ) and the D u b i n i n e q u a t i o n ( e q u a t i o n 1 3 ) are so g e n e r a l i n form t h a t c o n f o r m i t y t o e i t h e r o f them cannot be t a k e n as e v i d e n c e f o r the model t h e y r e p r e s e n t . -89-H - The Work of H a r r i s and Sing A paper by H a r r i s (149) compared an average pore ra d i u s , r^., determined by the K e l v i n equation w i t h the average pore r a d i u s as determined by the equation: ( G u r v i t c h mean pore r a d i u s ) . g o b0.08 The adsorbents used were t i t a n i a s and aluminas s p e c i a l l y prepared w i t h very narrow pore s i z e d i s t r i b u t i o n s i n each sample. The average K e l v i n r a d i u s as determined by H a r r i s (149) was determined from the p a r t i a l pressure at the poin t of steepest descent of the des o r p t i o n isotherm. H a r r i s (150) s t a t e s that t h i s method has been shown to compare favourably w i t h the various pore s i z e d i s t r i b u t i o n t e c h -niques f o r des o r p t i o n isotherms i n which almost a l l de-s o r p t i o n occurs over a small pressure range ( i . e . narrow pore s i z e d i s t r i b u t i o n ) . This assumption i s not v a l i d f o r c e l l u l o s i c m a t e r i a l s which have a wide pore s i z e d i s t r i b u t i o n . The r e s u l t s of Stone and S c a l l a n (35) show t h i s ; t h e i r mean pore s i z e was found to be 30-35 ft whereas the most common (steepest descent on the desorption isotherm) pore s i z e was found to be i n the 18-20 ft range. H a r r i s (150) assumed that monolayer coverage occurred at p/p Q = 0.08. He used t h i s method of determining the surface area, S, as he claims the B.E.T. equation does not apply to the m a t e r i a l s he s t u d i e d (151). He a l s o -90-c a l c u l a t e d V from the amount of gas adsorbed at p/p = 0.9 (152).. Stone and S c a l l a n used p/p =0.965 (35). Figure 18 shows the r e s u l t s of t h i s comparison. From these r e s u l t s , H a r r i s concludes the K e l v i n equation f o r a n i t r o g e n isotherm i s not a p p l i c a b l e to pores below about 18 ft r a d i u s , or approximately the upper s i z e l i m i t of a micro-pore as defined by Dubinin. He a l s o concludes that a l l smaller pores i n d i c a t e a radius of about 18 ft. Thus i f pores of l e s s than 18 ft radius are present, they w i l l appear as 18 ft radius pores. In h i s paper comparing the Gu r v i t c h and Kelvin.pore r a d i i , H a r r i s also concludes that the desorption i n pores of 18 ft ra d i u s or l e s s appears to be governed by a mechanism : dependent only on the adsorbate and the temperature, and independent of the pore s i z e of the adsorbent (149). He . discusses the mechanism of desorption and concludes (150): "that at a pressure which i s c h a r a c t e r i s t i c of the adsorbate and the temperature, but not the adsorbent, the mechanism of desorption changes from one c o n t r o l l e d by the K e l v i n equation to one c o n t r o l l e d by a surface migration i n t o and out of the micropore." • In another paper (153) H a r r i s s t a t e s : "A c e r t a i n amount of evidence i s being accumulated (149,153,154) which i n d i c a t e s that below a c e r t a i n pore s i z e , bulk l i q u i d p r o p e r t i e s cease to apply to the ad-sorbed phase, and that t h i s l i m i t depends both on the adsorbate and temperature, but not on the adsorbent provided only that the pores are s u f f i c i e n t l y s m a l l . " H a r r i s (155) a l s o s t a t e s that the l i m i t i n g pore radius i s 18 ft f o r ni t r o g e n and 14 ft f o r argon, both at 77 °K. This i s close to the upper s i z e l i m i t f o r a micropore as defined by Dubinin. In the same paper H a r r i s remarks: - 9 1 -i I I I I I 15 20 25 30 35 AO KELVIN PORE RADIUS ( A ) FIGURE 18: COMPARISON OF AVERAGE PORE SIZE AS CALCULATED BY KELVIN AND GURVITCH EQUATIONS (PHOTO FROM I49) -92-"While i t i s now accepted that the concept of surface t e n s i o n has to be modified i n a micropore, t o t a l pore volume continues to. be c a l c u l a t e d f o r microporous s o l i d s from the isotherm i n the same way as f o r s o l i d s w i t h t r a n s i t i o n a l or l a r g e r pores using the bulk value of the l i q u i d d e n s i t y . " H a r r i s then gives some data ( f i g u r e 19 )using argon, n i t r o g e n , oxygen and carbon monoxide as adsorbates over a range of tern-, peratures on a sample of porous t i t a n i a with a Gurvitch mean pore " r a d i u s " of about 11 &. These adsorbates have s i m i l a r molecular s i z e s and b o i l i n g p o i n t s , so d i f f e r e n c e s i n pene-t r a t i o n would not be expected. He ex p l a i n s the anomalous, slope of the apparent pore volume as determined by oxygen as probably a r i s i n g from the a b i l i t y of oxygen to penetrate the l a t t i c e of t i t a n i a i n a manner which i s not p o s s i b l e with . the other gases used. Prom t h i s data he concludes: "Thus i t appears that a micropore can be defined as one i n which the adsorbed phase no longer shows any of the p r o p e r t i e s of the bulk l i q u i d , so that the t o t a l pore volume determined by the usual method i s not more r e -l i a b l e or meaningful than surface area or pore radius determinations when a p p l i e d to microporous s o l i d s . " I - " f P l o t Method f o r A n a l y s i s of Adsorption Isotherms The " t " p l o t method f o r a n a l y s i s of adsorption i s o -therms proposed by Lippens and de Boer (156) has i n recent years a t t r a c t e d a good deal of a t t e n t i o n as a simple and d i r e c t means of i n t e r p r e t i n g n i t r o g e n adsorption isotherms and c h a r a c t e r i z i n g the p o r o s i t y of s o l i d adsorbents (157). The method c o n s i s t s of p l o t t i n g the volume of ni t r o g e n adsorbed on the s o l i d under i n v e s t i g a t i o n against the corresponding t h i c k n e s s , t , of the adsorbed l a y e r of n i t r o g e n on a nonporous FIGURE 19. (FROM REFERENCE 155.) APPARENT VOLUME OF MICROPOROUS TITANIA AS FUNCTION OF TEMPERATURE 0.!5r I ADSORBATES. _ . • • 0I4L O.I3h I — 1 I L. 60 70 80 90 TEMPERATURE, #K -94-reference s o l i d . E a r l i e r work (157) had demonstrated-that n i t r o g e n isotherms on various nonporous s o l i d s may be superimposed when p l o t t e d i n a reduced form ( i . e . v / v verses p/p ). Dev i a t i o n s from t h i s standard isotherm may be analysed i n terms of micropore f i l l i n g and c a p i l l a r y condensation. The slope of a l i n e a r " t " - p l o t provides a measure of the surface area and the onset of c a p i l l a r y condensation i s revealed by the departure of the " t " - p l o t from l i n e a r i t y . Lippens and de Boer (156) discussed the i n t e r -p r e t a t i o n s of the " t " - p l o t d e v i a t i o n s at higher r e l a t i v e pres-sures and i n t e r p r e t e d some cases shown i n f i g u r e 20. a) Curve I : The surface i s f r e e l y a c c e s s i b l e up to high r e l a t i v e pressures; the m u l t i l a y e r can form un-hindered on a l l p a r t s of the s u r f a c e ; the a d s o r p t i o n branch of the isotherm has the shape of the standard isotherm ( i . e . the p l o t i s l i n e a r ) . b) Curve I I : At a c e r t a i n pressure c a p i l l a r y condensation w i l l occur i n pores of c e r t a i n shapes and dimensions; the m a t e r i a l takes up more adsorbate than corresponds to the volume of the m u l t i l a y e r . The dotted s e c t i o n of t h i s curve was i m p l i e d by Lippens and de Boer, to mean that a f t e r c a p i l l a r i e s are f i l l e d , the slope of the " t " - p l o t decreased as the surface of the pore i s no longer a v a i l a b l e f o r the a d s o r p t i o n of n i t r o g e n . de Boer and h i s co-workers (158) have e x p l o i t e d t h e i r " t " - p l o t f o r the i n t e r p r e t a t i o n of n i t r o g e n isotherms on v a r i o u s porous s o l i d s (Al^O,, T i 0 9 , BaSCv, ZrO„, MgO, N i c k e l a n t i g o r i t e , S i 0 2 and c a r b o n b l a c k s ) . I t w o u l d a p p e a r t h a t t h e y have assumed c o v e r a g e t o o c c u r w i t h i n m i c r o p o r e s as i t d o e s i n l a r g e r p o r e s . Thus t h e s u r f a c e a r e a i n m i c r o -p o r e s has b e e n c a l c u l a t e d f r o m t h e s l o p e o f t h e " t " - p l o t a t l o w r e l a t i v e p r e s s u r e s . S i n g (159) c o n c l u d e d t h i s a p p r o a c h i s n o t r e a l i s t i c a n d e x p l a i n e d h i s r e a s o n s u s i n g c u r v e I I I o f f i g u r e 20 as f o l l o w s : I n c a s e s where a r e l a t i v e l y s h o r t l i n e a r r e g i o n o f t h e " t " - p l o t ( e . g . AB i n c u r v e I I I o f f i g u r e 20) i s f o l l o w e d by a r e g i o n o f r e s t r i c t e d a d s o r p t i o n ( B D ) , i t i s more r e a s o n a b l e t o s u p p o s e t h a t t h e i n i t i a l p a r t i s made up o f b o t h m i c r o p o r e f i l l i n g a n d s u r f a c e c o v e r a g e ( o f l a r g e r p o r e s ) and i f t h i s i s so i t i s c l e a r t h a t t h e i n i t i a l , s l o p e c a n n o t be u s e d t o p r o v i d e a m e a n i n g -f u l v a l u e o f t h e s u r f a c e a r e a . B e c a u s e o f t h e n a t u r e o f t h e c a l c u l a t i o n , g o od a g r e e m e n t b e t w e e n S T and SgErp i s o n l y t o be e x p e c t e d a n d does n o t i n i t s e l f c o n f i r m t h e v a l i d i t y o f e i t h e r v a l u e o f s u r f a c e a r e a . ; I f t h e " t " - p l o t i s made up o f two l i n e a r p a r t s , AB a n d CD, i t w o u l d seem more r e a s o n a b l e t o t a k e t h e s e c o n d , . CD, as t h a t c o r r e s p o n d i n g t o m o n o l a y e r - m u l t i l a y e r a d s o r p t i o n on t h e s u r f a c e o f a l l p o r e s e x c e p t m i c r o - , p o r e s . B a c k w a r d e x t r a p o l a t i o n o f DC t o t h e V a x i s w i l l t h e n p r o v i d e t h e e f f e c t i v e o r i g i n 0' f o r t h e m o n o l a y e r - m u l t i l a y e r a d s o r p t i o n p r o c e s s a n d t h e u p -t a k e a t 0' w i l l i n t u r n g i v e a m e a s u r e o f t h e m i c r o p o r e v o l u m e . A s s u m i n g l i q u i d p a c k i n g o f t h e a d s o r b e d n i t r o g e n m o l e c u l e s , v M J C R O P O R E = °- 0 0 156 V q , T h i s s i m p l e method o f a n a l y s i s a p p e a r s t o o f f e r t h e i m p o r t a n t a d v a n t a g e o v e r t h e D u b i n i n a p p r o a c h t h a t no d i s t r i b u t i o n o f s o r p t i o n e n e r g i e s has t o be assumed t o a s s e s s m i c r o -p o r e f i l l i n g , b u t i t i s o f c o u r s e b a s e d on t h e a s s u m p t i o n t h a t t h e l i n e a r r e g i o n CD i s e n t i r e l y f r e e f r o m t h e c o m p l i c a t i o n o f c a p i l l a r y c o n d e n s a t i o n . " H o wever, d e v i a t i o n s f r o m l i n e a r i t y a t l o w r e l a t i v e p r e s s u r e s ( l o w " t " v a l u e s ) i n t h e d i r e c t i o n o f i n c r e a s e d a d -s o r p t i o n c o u l d be due t o m i c r o p o r e f i l l i n g , i n c r e a s e d a d -s o r p t i o n due t o t h e e n h a n c e d p o t e n t i a l f i e l d (105) o r a com-b i n a t i o n o f c h e m i s o r p t i o n and p h y s i c a l a d s o r p t i o n o r any com-b i n a t i o n o f t h e s e p o s s i b i l i t i e s . -97-V - APPARATUS, MATERIALS AND EXPERIMENTAL PROCEDURES A- I n t r o d u c t i o n Two types of gas adsorption apparatus were con-s t r u c t e d f o r t h i s work; a continuous flow device f o r deter-mining small surface areas such as those of paper sheets and a v o l u m e t r i c device f o r determining complete isotherms. A supplementary piece of equipment was b u i l t f o r the solvent exchange d r y i n g of pulp and paper samples. Bo D e s c r i p t i o n of M a t e r i a l s Used The f i b r e s used throughout the experiments came from a s i n g l e sample of never d r i e d , f u l l y bleached, commercial grade k r a f t pulp obtained from the MacMillan-Bloedel Co. L t d . , Harmac d i v i s i o n at Nanaimo, B. C. The pulp was a blend of c o a s t a l Douglas f i r and western hemlock. A few drops of form-aldehyde were added to stop b i o l o g i c a l degradation. The sample was kept under r e f r i g e r a t i o n at a l l times. S p e c i f i c a t i o n s of the gases and chemicals used are l i s t e d i n appendix E. C. Continuous flow Adsorption Apparatus The continuous flow method of determining surface area was developed by Nelsen and Eggertsen (160) and adapted by Stone and Nickerson ( l 6 l ) f o r use on paper sheets. The equip-ment constructed f o r t h i s work i s b a s i c a l l y the same as that developed by Stone and Nickerson and i s s c h e m a t i c a l l y des-c r i b e d i n f i g u r e s 21 and 22. The continuous flow method i s based on the changes of the thermal c o n d u c t i v i t y of the gas mixture w i t h composition. A known mixture of n i t r o g e n and helium i s passed through the sample w i t h the e f f l u e n t being monitored by a thermal - 9 8 -FIGURE. 21. BASIC UNITS Cf CONTINUOUS FLOW EQUIPMENT THERMAL CONDUCTIVITY PURE NITROGEN MILUVOLT RECORDER OF LIQUID NITROGEN A "ADSORPTION PEAK D ~ DESORPTION PEAK C -CALIBRATION PEAK NITROGEN THERMOMETER PROBES 12 V POWER SOURCE BACK PRE-SSURE MANOMETER He-N 2 MIXTURE FEED EXHAUST THERMAL ^CONDUCTIVITY CELL TO MILLIVOLT RECORDER SAMPLE TUBES" DEWAR FLASK LIQUID N 2 cr bl tj Z o Z < UJ ct 3 </> CO 8 ae 3 O a. 2 NITROGEN THERMOMETER PURIFIED NITROGEN OIL FILLED SRINGE CAPS FOR CALIBRATION M EXHAUST FIGURE 22: SCHEMATIC DIAGRAM OF CONTINUOUS FLOW EQUIPMENT -100-conductIvi.ty. c e l l coupled to an i n t e g r a t i n g m i l l i v o l t r e -corder. When the system i s i n e q u i l i b r i u m as i n d i c a t e d by a constant b a s e l i n e on the recorder chart,, the sample tube i s immersed i n a l i q u i d n i t r o g e n bath;- adsorption of ni t r o g e n by the paper i s i n d i c a t e d by a peak on the recorder chart i n d i c a t i n g the change i n composition of the gas mixture. As e q u i l i b r i u m i s again e s t a b l i s h e d , the chart pen w i l l r e t u r n to the o r i g i n a l p o s i t i o n . The l i q u i d n i t r o g e n bath i s then removed a l l o w i n g the sample to warm up thereby desorbing the adsorbed n i t r o g e n . This desorbed n i t r o g e n i s detected by the thermal c o n d u c t i v i t y c e l l and t h i s causes a peak on the opposite side of the base l i n e to appear. The volume of nitrogen represented by these two peaks should be the same and the volumes represented are determined by c a l i b r a t i o n of the detector. This c a l i b r a t i o n i s obtained by i n j e c t i n g known q u a n t i t i e s of pure n i t r o g e n or helium i n t o the stream and monitoring the r e s u l t i n g peak s i z e s . As the composition of the helium-nitrogen gas mixture i s known, and the s a t u r a t i o n pressure of the l i q u i d n i t r o g e n can be determined from the . ni t r o g e n vapour pressure thermometer, the p a r t i a l pressure of nit r o g e n can be determined. ; The packing of the sample i n t o the sample tube i s .very important i f good r e s u l t s are to be obtained. Large dead spaces must be avoided and a l l surfaces should be a c c e s s i b l e to the f l o w i n g gas i n order to avoid long delays while the ni t r o g e n d i f f u s e s to or from the sample surface. Handsheets, were cut i n t o 4 x 20 mm s t r i p s and about one gram was l o o s e l y packed i n t o the sample tube described i n f i g u r e 23a. ! GLASS SPACER 7 mm TUBING 6 mm CAPILLARY TUBING OUT THINLY. FIG.23a SAMPLE TUBE FOR FIG. 23b SAMPLE TUBE FOR PAPER SAMPLES. POWDER SAMPLES. S A M P L E TUBES FOR CONTINUOUS FLOW ADSORPTION EQUIPMENT. -102-The equipment has been used by other workers (162) f o r surface area measurements of m a t e r i a l s such as galena and marmatite powders of 65/1.00 mesh s i z e . In t h i s case, a sample tube of the shape given i n f i g u r e 23-b was used. These mineral samples represented a unique problem i n that the adsorption took a minimum of ten minutes to complete because of the d i f f i c u l t y of c o o l i n g the p a r t i c l e s to l i q u i d n i t r o g e n temperatures. Thus, as Nelson; and Eggertson found (160), only desorption peaks could be used on such samples. This problem was not encountered'when using paper samples and thus both adsorption and desorption peaks could be used. The samples of paper were d r i e d by passing a stream of the He-N 2 mixture at about 20 mis per minute through them f o r f i v e minutes and then immersing the sample i n an a i r a g i t a t e d o i l bath at 105 °C f o r 30 minutes. P r o v i s i o n was al s o made f o r the venting of the moisture c o n t a i n i n g exhaust gas immediately a f t e r the sample tube. Once the samples' were d r i e d , the system was closed and the flow of the He-N2 mixture adjusted to 15 mis per min. as measured by the soap bubble flow meter. When e q u i l i b r i u m was e s t a b l i s h e d , as shown by a constant zero tr a c e on the .re-cording m i l l i v o l t m e t e r monitoring the thermal c o n d u c t i v i t y c e l l , the sample was slowly immersed i n the l i q u i d n i t r o g e n , bath. A slow immersion (up to 5 minutes) was r e q u i r e d to : avoid d i s t u r b i n g the flow e q u i l i b r i u m . The vapour pressure. of the l i q u i d n i t r o g e n bath and the thermal c o n d u c t i v i t y c e l l output were recorded as the system'returned to e q u i l i b r i u m . -103-A f t e r the e q u i l i b r i u m was r e - e s t a b l i s h e d , the l i q u i d n i t r o g e n bath was removed from the sample. Again the vapour pressure and thermal c o n d u c t i v i t y c e l l output were recorded. This proceedure was repeated s e v e r a l times u s u a l l y interspaced with c a l i b r a t i o n samples which were i n j e c t e d using a gas sy r i n g e . These c a l i b r a t i o n samples were s i z e d to bracket the volume of the experimental a d s o r p t i o n . Three N2~He r a t i o s (5.06, 15.60 and 25.38 percent n i t r o g e n i n helium) were used, the system being purged f o r each gas used. A c a l i b r a t i o n was r e q u i r e d f o r each sample. D. The Volumetric Apparatus The volumetric a d s o r p t i o n equipment constructed f o r t h i s work i s s i m i l a r to the standard volumetric equipment described by Gregg and Sing (20) w i t h emphasis on reducing the dead volume as much as p o s s i b l e . Figure 2 4 i s a schematic drawing of t h i s apparatus, the equipment i s con-s t r u c t e d of 1 mm i n s i d e diameter c a p i l l a r y t u b i n g w i t h matching 5.5 mm c a l i b r a t e d tubes f o r the pressure manometer. A l l measurements are taken using a cathetometer capable of measure-ment to 0.001 cm. When using the equipment wi t h solvent exchange d r i e d pulps the sample was connected while s t i l l immersed i n n-pentane. The sample tube was then Immersed i n a water bath at 20 °C and the n-pentane p u l l e d o f f by vacuum pumping at a ra t e which r e q u i r e d 3 to 4 hrs. f o r the solvent to disappear. The sample was then evacuated f o r at l e a s t 12 hours under a vacuum of about 5 microns pressure. For samples not solvent exchanged, 12 hours evacuation at 5 microns pressure removed VACUUM PUMP McLEOD K GAUGE 0 CAU8RA1 'VOLUME BULBS PRESSURE MANOMETER GAS CYLINDER VAPOUR PRESSURE MANOMETER GAS STORAGE 0 VAPOUR PRESSURE PROBE SAMPLE TUBE FIGURE 24. VOLUMETRIC ADSORPTION APPARATUS -105-any v o l a t i l e s present.. The sample was i s o l a t e d under the vacuum and the balance of the system f l u s h e d with the gas to be used. For the l a s t f l u s h i n g the sample tube was r e -opened to the system. The t e s t s e c t i o n was pumped down' to the de s i r e d pressure, the pressure measured, and the sample tube immersed i n l i q u i d n i t r o g e n . E q u i l i b r i u m was assumed, when two readings at l e a s t two minutes apart were i d e n t i c a l . A d d i t i o n a l q u a n t i t i e s of gas were introduced to the sample by slowly f i l l i n g the gas r e s e r v o i r bulbs with mercury, or by i s o l a t i n g the sample, i n c r e a s i n g the pressure of the r e s t of the t e s t s e c t i o n and slowly bleeding t h i s increased pressure i n t o the sample tube. The vapour pressure of the l i q u i d n i t rogen was measured each time by means of the vapour pressure thermometer. The l e v e l of the l i q u i d n i t r o g e n was.maintained constant. For points on the desorption isotherm, gas was removed i n a manner analogous to the method used i n adsorption except that gas was removed r a t h e r than added. The whole system was kept at a f a i r l y constant temperature which was measured to 0.1 °F and the temperature dependent v a r i a b l e s were correc t e d to a base temperature of 20 °C. The atmospheric pressure was measured on a barometer accurate to 0.0025 cm Hg. Sample packing was a c r i t i c a l parameter. I t was'found that f o r solvent exchanged from wet st a t e pulps,.the best r e -s u l t s were obtained with a sample tube made out of 7 mm glass tubing. The pulp was packed c o n c e n t r i c a l l y around a 2 mm glass rod while the tube assembly was immersed i n d i s t i l l e d water. The pulp f i b r e s were dispersed i n the water and gently packed - 105 a -down w i t h m i n i m a l p r e s s u r e t o l e a v e c l e a r a n c e b e t w e e n f i b r e s . The two-mm t u b e i n t h e c e n t r e was r e m o v e d a f t e r s o l v e n t e x -c h a n g e d r y i n g . The p a p e r s h e e t s w e r e p a c k e d i n a m a n n e r s i m i l a r t o t h a t u s e d i n t h e c o n t i n u o u s f l o w a p p a r a t u s . The w e i g h t o f s a m p l e was v a r i e d t o g i v e a b o u t 10-25 s q . m. o f s u r f a c e a r e a i n t h e t u b e . -106-E. Solvent E x t r a c t i o n Apparatus While the solvent exchange technique f o r r e t a i n i n g the water swollen s t r u c t u r e of c e l l u l o s e has been questioned i n s e c t i o n I I of t h i s work, the d e c i s i o n to use t h i s technique was made because no s a t i s f a c t o r y a l t e r n a t e was thought to e x i s t . The solvent e x t r a c t i o n equipment i s shown i n f i g u r e 25. The methanol and n-pentane were stored over magnesium t u r n i n g s and c l e a n , f i n e l y d i v i d e d sodium metal r e s p e c t i v e l y . The methanol was r e f l u x e d over magnesium tu r n i n g s f o r a minimum o f 30 minutes p r i o r to the sample being connected. An e x t r a c t i v e flow r a t e of about 100 ml./hour was used where p o s s i b l e (the h e a v i l y beaten pulps r e s t r i c t e d flow too much f o r flows of t h i s magnitude). In a l l cases, 350-400 mis o f methanol were e l u t e d through the sample. The d i s -t i l l a t i o n f l a s k had magnesium tu r n i n g s to act as dehydrating agent and b o i l i n g c h i p s . The n-pentane was r e f l u x e d over the sodium metal f o r a minimum of 30 minutes p r i o r to the beginning of the ex-t r a c t i o n . Care was taken at a l l times to avoid p o s s i b l e con-t a m i n a t i o n of the sample wi t h moisture i n c l u d i n g atmospheric moisture. Again the solvent flow was held to about 100 mis./ hour w i t h a t o t a l e x t r a c t i v e flow of about 350-400 mis. When the solvent e x t r a c t i o n was complete, the sample tube was removed from the solvent e x t r a c t i o n equipment and capped t o avoid p o s s i b l e contamination w i t h atmospheric moisture. The d r a i n was sealed with a g l a s s blowing t o r c h . •107-FIGUKE 25. SOLVENT EXTRACTION A P P A R A T U S TUBE PACKED WITH FRESHLY REGENERATED SILICA GEL ^ BALL JOINT 2 mm TUBlWG SAMPLE 7 lam TUBING SAMPLE TUBE -108-The sample was then connected to the volumetric apparatus. F. Beating of Pulp The pulp was beaten i n a P.F.I, m i l l f o r various lengths of time w i t h a l l other c o n d i t i o n s being held con-stant at the c o n d i t i o n s l i s t e d below: S i z e of charge: 20g. (dry pulp) at 10% s o l i d s l o a d i n g : 3-4 Kg/cm of bar length The pulp samples were beaten as f o l l o w s : Time beaten No. of r e v o l u t i o n s 1 minute 1,470 3 minutes 4,450 5 minutes 7,430 10 minutes 14,950 F i v e samples were beaten at each l e v e l , d i l u t e d t o f i v e percent s o l i d s c o n c e n t r a t i o n and blended. The r e -s u l t i n g lOOg samples were used throughout the experiments. G. Paper T e s t i n g Handsheets were made i n conformance w i t h CP.P.A. Standard C-4. The sheets were d r i e d , c o n d i t i o n e d and t e s t e d i n a room maintained at 72 °F and 50 percent r e l a t i v e humidity. Tear t e s t s and burst t e s t s were performed i n conformance w i t h CP.P.A. Standards D-9 and D-8 r e s p e c t i v e l y . T e n s i l e t e s t s were performed on an I n s t r o n model TM-L t e n s i l e t e s t e r i n accordance w i t h CP.P.A. Standard D-6. Sheet thicknesses were determined on a T e s t i n g Machines, Inc. micrometer model 549 i n accordance w i t h CP.P.A. Standard D-4. - 1 0 9 -H. Experiments Performed F r a c t i o n s of the main bulk sample were beaten one, t h r e e , f i v e and ten minutes i n the P.F.I, m i l l as described p r e v i o u s l y . The Canadian Standard Freeness of each of these pulps was determined. Unbeaten and beaten pulps were solvent exchange d r i e d from a water suspension. Nitrogen and argon isotherms were determined on each of these solvent exchange d r i e d samples. Oxygen isotherms were determined on the unbeaten, beaten one minute and beaten three minutes samples. Some samples were d u p l i c a t e d . Samples of never d r i e d , unbeaten pulp were a i r d r i e d to v a r i o u s moisture contents and then solvent exchange d r i e d . A handsheet sample was a i r d r i e d and then vacuum d r i e d at 5 microns pressure, the sample tube f i l l e d w i t h n i t r o g e n and then the sample was solvent exchange d r i e d . Throughout t h i s work, t h i s sample i s r e f e r r e d to as the vacuum d r i e d - solvent exchange d r i e d sample. Nitrogen i s o -therms were determined on a l l samples. An oxygen isotherm was determined on the vacuum d r i e d - solvent exchange d r i e d sample. Argon isotherms were determined on the vacuum d r i e d - solvent exchange d r i e d sample and the 5-3 percent moisture content sample. Isotherms of n i t r o g e n , argon and oxygen were de t e r -mined on vacuum d r i e d , unbeaten handsheets which were not solvent exchange d r i e d . The continuous flow a d s o r p t i o n apparatus was used to determine the B.E.T. surface area of handsheets of a l l the -110-pulps used. Handsheets were made from these pulps f o r p h y s i c a l t e s t i n g . T e n s i l e , s t r e t c h , sheet d e n s i t y , burst and t e a r were determined on each set of handsheets. -111-VI - EXPERIMENTAL RESULTS AND DISCUSSION A. I s o t h e r m s , of N i t r o g e n , Argon and Oxygen N i t r o g e n and argon i s o t h e r m s on d u p l i c a t e samples o f s o l v e n t exchange d r i e d p u l p s are shown i n f i g u r e s 26-28. These i s o t h e r m s show the r e p r o d u c i b i l i t y o f the e x p e r i -m e n t a l t e c h n i q u e s . Any d i f f e r e n c e s c o u l d be due t o d i f f i c u l t i e s w i t h s o l v e n t exchange d r y i n g as t h i s t e c h n i q u e i s a p p a r e n t l y q u i t e s e n s i t i v e t o p a c k i n g and t h u s t h e l e s s a c c e s s i b l e f i b r e s may not be as c o m p l e t e l y s o l v e n t exchange d r i e d . A p pendix I i s a s t u d y o f t h e p o s s i b l e e r r o r s i n t h e v o l u m e t r i c a p p a r a t u s and t h e e f f e c t t h e s e e r r o r s have on t h e c a l c u l a t e d v a l u e s d e t e r m i n e d i n t h i s work. Appendix K compares d a t a c a l c u l a t e d from d u p l i c a t e samples. The d a t a .given I n a p p e n d i c e s I and K show t h e e f f e c t s o f t h e p a permaking p a r a m e t e r s s t u d i e d i n t h i s work are m e a s u r a b l e and not due t o e r r o r . The s u p e r i m p o s a b i l i t y o f s e q u e n t i a l a d s o r p t i o n i s o t h e r m s f o r n i t r o g e n and argon i s shown i n f i g u r e s 26 and 28. The s e q u e n t i a l i s o t h e r m s were d e t e r m i n e d c o n t i n u o u s l y , w i t h t h e second i s o t h e r m b e i n g a c o n t i n u a t i o n o f t h e f i r s t i s o t h e r m . These s e q u e n t i a l i s o t h e r m s show t h a t t h e de-s o r p t i o n I s o t h e r m i s v e r y dependent on t h e r e l a t i v e p r e s s u r e t o w h i c h t h e a d s o r p t i o n i s o t h e r m i s t a k e n b e f o r e t h e de- • s o r p t i o n i s o t h e r m i s s t a r t e d . The second d e s o r p t i o n i s o t h e r m s were commenced from l o w e r r e l a t i v e p r e s s u r e s t h a n t h e f i r s t and t h e r e s u l t i n g d e s o r p t i o n i s o t h e r m s a r e s i g n i f i c a n t l y d i f f e r e n t as can be seen from f i g u r e s 26 and 28. The argon d e s o r p t i o n - I l l a -i s o t h e r m i s more s e n s i t i v e t h a n t h e n i t r o g e n one t o t h i s e f f e c t . Thus a h i g h r e l a t i v e p r e s s u r e i s r e q u i r e d p r i o r t o b e g i n n i n g t h e d e s o r p t i o n i s o t h e r m i n o r d e r t o a s s u r e com-p a r a b l e d e s o r p t i o n i s o t h e r m s . I s o t h e r m s o f n i t r o g e n , a r g o n a nd o x y g e n a t 78 °K were d e t e r m i n e d on s o l v e n t e x c h a n g e d r i e d wood p u l p s a n d a r e shown i n f i g u r e s 29 t o 37. F i g u r e 38 shows t h e n i t r o g e n , a r g o n a n d o x y g e n i s o t h e r m s onto, vacuum d r i e d u n b e a t e n wood p u l p h a n d s h e e t s . The d a t a f o r t h e s e i s o t h e r m s a r e l i s t e d i n A p p e n d i x A. -112-280 FIGURE 26 NITROGEN ISOTHERMS ON DUPLICATE SOLVENT EXCHANGE DRIED UNBEATEN PULP SAMPLES o FIRST ISOTHERM • SECOND ISOTHERM A SAMPLE 2. - 1 1 3 -260 240 200 IT 560 FIGURE 27. NITROGEN ISOTHERMS ON DUPLICATE I- SOLVENT EXCHANGE DRIED PULP BEATEN FOR 10 MIN. IN RF.I. MILL o SAMPLE I. A SAMPLE 2. SOLID POINTS = DESORPTION <» g 120 Q UJ CO CC o g 80 3 o 40 -114-280 -240 200 N a: co E a UJ CD OC O CO o < LU 2 3 o > 160 120 80 40 FIGURE 28. ARGON ISOTHERMS ON DUPLICATE SOLVENT EXCHANGE DRIED UNBEATEN PULP SAMPLES O FIRST CYCLE • SECOND CYCLE A SECOND ISOTHERM ISOTHERM ONE SOLID SYMBOLS = DESORPTION 0*0 0.2 0.4 0.6 P / P o 0.8 1.0 - 1 1 5 --116--117--118-280r 240 FIGURE 32. ISOTHERMS OF NITROGEN AND ARGON AT 78° K ON SOLVENT EXCHANGE DRIED PULP BEATEN 5 MIN. a: CO 200 160 a ui m g 120 co Q < Ul o > o NITROGEN A ARGON SOLID SYMBOLS ARE DESORPTION -119-280 240 200 \ 160 a? Hf co i2 120 E Q LU 00 CC o 80 CO a < LU -I O > FIGURE 33. ISOTHERMS OF NITROGEN 8 ARGON AT 78°K ON SOLVENT EXCHANGE DRIED PULP BEATEN 10 MIN. O NITROGEN A ARGON SOLID SYMBOLS ARE DESORPTION y - 1 2 1 -6 D r 0.0 0.2 0 . 4 0 . 6 0*8 1.0 -122--124-l.4| l.2h 1.0 0L </5 0.81 FIGURE 38. ADSORPTION ISOTHERMS OF NITROGEN, ARGON AND OXYGEN ON VACUUM DRIED UNBEATEN PULP SHEETS o NITROGEN A ARGON Q 0.6 Id CO DC o o * 0.4| 2 O > 0.2 • OXYGEN SOLID SYMBOLS • DESORPTION 0.0» o % A ****** * 0.0 0.2 0.4 0.6 P/ P« 0.8 -125-de Boer (page 172 of reference 20) has c l a s s i f i e d h y s t e r e s i s loops and r e l a t e d these c l a s s i f i c a t i o n s to d e f i n i t e pore shapes. However, i n order to do t h i s success-f u l l y , an adsorbent with a very narrow pore d i s t r i b u t i o n i s r e q u i r e d . Otherwise, the h y s t e r e s i s loop w i l l be a com-p o s i t e of the ov e r l a p p i n g c o n t r i b u t i o n s from the .various pore s i z e s and the h y s t e r e s i s shape may be q u i t e d i f f e r e n t from that p r e d i c t e d by the pore geometry. The shapes of the h y s t e r e s i s loops obtained i n t h i s work are not acceptable f o r t h i s type of i n t e r p r e t a t i o n as there apparently are wide pore s i z e d i s t r i b u t i o n ' s . The shape of the h y s t e r e s i s loops found by adsorption of n i t r o g e n , argon and oxygen on c e l l u l o s e could f i t any of s e v e r a l pore shapes i n c l u d i n g the c y l i n d r i c a l and p a r a l l e l sided f i s s u r e models. The shapes of the n i t r o g e n , argon and oxygen ad-s o r p t i o n isotherms i n d i c a t e that the argon isotherm i n t e r -cepts the s a t u r a t i o n pressure (p/p = 1.0) w i t h a f i n i t e ad-s o r p t i o n value whereas the n i t r o g e n and argon isotherms apparently approach the s a t u r a t i o n pressure a s y m p t o t i c a l l y . The s i m i l a r i t y between the shape of the n i t r o g e n and oxygen isotherms on solvent exchange d r i e d water swollen pulps and the shape of the n i t r o g e n and oxygen isotherms on mont-m o r i l l o n i t e which are shown i n f i g u r e 39 i s s t r i k i n g . The. isotherms on m o n t m o r i l l o n i t e have been i n t e r p r e t e d to mean that m o n t m o r i l l o n i t e contains laminae which open up as ad-- 1 2 6 -FIGURE 39 (FROM REFERENCE 163) ISOTHERMS ON MONTMORILLONITE -127-s o r p t l o n proceeds forming p a r a l l e l sided pores (150, 163). There i s no l i m i t to adsorption. On des o r p t i o n , a meniscus i s present which causes h y s t e r e s i s . I t i s the r e f o r e suggested that p o s s i b l y the solvent exchange d r i e d pulps, which may al s o have a f l a t p l a t e s t r u c t u r e (model proposed by Stone (16,35)) do behave i n a manner s i m i l a r to montmorillonite at higher r e l a t i v e pressures, p a r t i c u l a r l y with diatomic adsorbates.. One would expect t h i s e f f e c t to occur more r e a d i l y w i t h a diatomic molecule than a monatomic molecule because of the; p o s s i b i l i t y of induced p o l a r i z a t i o n and thus more energetic adsorption of higher l a y e r s . Also c o n t r i b u t i n g to the more energetic adsorption of higher l a y e r s are the heats of vapour-i z a t i o n which i n d i c a t e a more energetic adsorption f o r the diatomic molecules. The heats of v a p o u r i z a t i o n (164) f o r nitr o g e n and oxygen are 85.3 and 96.6 B . t . u . / l b . r e s p e c t i v e l y but f o r argon the value i s only 72.6 B . t . u . / l b . * Other p o s s i b l e explanations f o r t h i s d i f f e r e n c e i n the shape of isotherms of the diatomic adsorbates, n i t r o g e n and oxygen and the monatomic adsorbate, argon, are: a) The outer adsorbed l a y e r s of argon, which i s assumed to behave as a super-cooled l i q u i d when adsorbed onto a s u r f a c e , may re v e r t to the s o l i d s t a t e which would be expected under the con d i t i o n s of the experiment. Thus the e f f e c t s of surface t e n s i o n are l o s t and the model of a K e l v i n equation c o n t r o l l e d condensation i s no longer a p p l i c a b l e , r e s u l t i n g i n no bulk conden-s a t i o n i n pores u n t i l s a t u r a t i o n pressure i s reached. * Ex t r a p o l a t e d bulk l i q u i d value -128-b) The " s t a n d a r d " a r g o n i s o t h e r m on a non p o r o u s c e l l u -l o s i c m a t e r i a l h a s no l a r g e i n c r e a s e i n t h e number o f l a y e r s a d s o r b e d a s t h e r e l a t i v e p r e s s u r e a p p r o a c h e s u n i t y . T h i s p o s s i b i l i t y I s d o u b t f u l as a r g o n a d s o r p t i o n on s i n g l e c r y s t a l s o f z i n c . (165) shows a r a p i d i n c r e a s e i n l a y e r s o f a r g o n a d -s o r b e d a t h i g h e r r e l a t i v e p r e s s u r e s . c ) The s a t u r a t i o n v a p o u r p r e s s u r e o f a r g o n s o l i d , a s m e a s u r e d by t h e a r g o n p r o b e , i s n o t t h e t r u e s a t u r a t i o n v a p o u r p r e s s u r e o f t h e s u p e r c o o l e d l i q u i d , t h u s t h e r e l a t i v e p r e s s u r e i s i n e r r o r , p o s s i b l y . b e i n g t o o l o w (166). B. B.E.T. A n a l y s i s o f I s o t h e r m s B.E.T. a n a l y s e s w e r e made on e a c h o f t h e i s o t h e r m s . B.E.T. p l o t s f o r n i t r o g e n , a r g o n a n d o x y g e n i s o t h e r m s o f t h e s o l v e n t e x c h a n g e d r i e d , u n b e a t e n p u l p a r e shown i n f i g u r e 40. T h e s e p l o t s a r e t y p i c a l o f t h e r e s u l t s o b t a i n e d . T a b l e 15 l i s t s t h e B.E.T. m o n o l a y e r v o l u m e s a n d s u r f a c e a r e a s o f t h e v a r i o u s s a m p l e s u s e d . The v a l u e o f A f o r n i t r o g e n i s ^ m & 2 a s s u m e d t o be t h e s t a n d a r d 16.2 ft t h r o u g h o u t t h i s w o r k u n l e s s o t h e r w i s e n o t e d . The v a l u e s o f A g i v e n i n t a b l e 15 a r e m & c a l c u l a t e d f r o m e q u a t i o n 4 u s i n g d e n s i t i e s (160) o f 1.452* and I.1967 g . / m l . f o r a r g o n a n d o x y g e n r e s p e c t i v e l y . E x t r a p o l a t e d f r o m l i q u i d d e n s i t i e s . - 1 2 9 -Table 15: B. E. T. Monolayer Volumes and. Areas of Solvent Exchange Dried Samples Sample B. E. T. Monolayer Volume, v , (mis.(S.T.P.)/g.) B. E. T. Area, A (sq.m./g.) Minutes Beaten 0 0 1 3 5 10 . 0 0 0 0 Moisture Content* Saturated Saturated Saturated Saturated Saturated Saturated Vacuum d r i e d 5-3 14.4 33.6 Nitrogen (A =16.2) & m v A m 44.28 193.0 44.37 193-4 41.75 182.0 38.65 168.5 36.22 157.8 36.99 161.3 1.187 5.17 1.677 7.31 5.109 22.27 28.15 122.7 Argon (Am=13.9) A 170.1 177.4 163.5 153.5 143.2 143.2 v m 45.38 47.32 43.61 40.95 38.2 38.2 1.307 1. 921 4.90 7.20 Oxygen (Am=12.5) v m 50.43 48.85 45. 54 1. 501 A 170.0 164.5 153.5 5.06 UJ o I * Wt. moisture x 100 / (wt. moisture + s o l i d s ) -130-^ Table 15 shows, the agreement between the B.E.T surface, areas determined by argon and oxygen a d s o r p t i o n . i s q u i t e good, however, the agreement between these values and those determined from the n i t r o g e n adsorption isotherms i s not as good, the ni t r o g e n values being about 10 percent higher. The r a t i o s of these surface areas are l i s t e d i n t a b l e 16. Table 16: Ratios Showing on Adsorbate Dependence of B.E .T. Surf, Sample Ratio of . Areas Minutes beaten Moisture Content Ar N j °2 N 2 °2 Ar 0 Saturated 0.88 0.88 1.00 0 Saturated 0.92 1 Saturated 0.90 0.90 1.01 3 • Saturated 0.91 0.91 . 1.00 5 Saturated 0.91 10 Saturated 0.89 0 Vacuum d r i e d 0.95 0.98 1.03 0 5-3 0.985 Some of the d e f i c i e n c i e s of the B.E.T. technique have been discussed i n s e c t i o n IV-A. These r e s u l t s de-monstrate the problem of assuming a p a r t i c u l a r c r o s s - s e c t i o n a l area, A , of an adsorbed molecule. The close agreement m ° between B.E.T. areas as determined from argon and oxygen isotherms may be f o r t u i t o u s or may be due to the s i m i l a r bulk p h y s i c a l p r o p e r t i e s (vapour pressure, c r i t i c a l p r o p e r t i e s , molal volume) of the two adsorbates. The bulk p h y s i c a l - 1 3 1 -p r o p e r t i e s of n i t r o g e n are s i g n i f i c a n t l y d i f f e r e n t . The improved agreement between the n i t r o g e n and argon on samples solvent exchange d r i e d from low water contents may be due to the f a c t that the pore volume d i s t r i b u t i o n ' i s s h i f t e d toward smaller pores i n these samples, (See f i g u r e 52 and s e c t i o n VI-G). The agreement between the B.E.T. surface areas apparently improves as the pore volume d i s t r i b u t i o n s h i f t s to the smaller pore s i z e s . However, the small q u a n t i t y of data permits only t e n t a t i v e ' . c o n c l u s i o n s . I f one forces the argon and oxygen data to agree wi t h .the n i t r o g e n data f o r solvent, exchange d r i e d swollen pulps, the values of the adsorbed molecular c r o s s - s e c t i o n a l 2 ' 2 areas, A , must be changed from 1 3 - 9 A and 1 2 . 5 ft to 2 2 15-4 ft and 1 3 - 9 ft f o r argon and oxygen r e s p e c t i v e l y . The p proposed molecular c r o s s - s e c t i o n a l area f o r argon, 15.4 ft , i s the value recommended by Emmett and Cines ( 1 6 6 ) f o r argon as a r e s u l t of t h e i r s t u d i e s on porous g l a s s . However, con-s i d e r i n g the conclusions of A r i s t o v and K i s e l e v ( 1 0 5 ) and the apparent agreement between the B.E.T. surface areas from argon and oxygen isotherms, i t might be more l o g i c a l to change the c r o s s - s e c t i o n a l area of n i t r o g e n from 1 6 . 2 to 14 . 6 ft to achieve agreement because argon would seem to be a more i d e a l adsorbent, as i t i s monatomic and non-reactive. The proposed 2 c r o s s - s e c t i o n a l area of 14 . 6 ft i s greater than the value of 2 14 . 2 ft recommended by Kodera and O n i s i ( 1 0 7 ) f o r general use 2 and i s between the values of 1 3 - 6 and 14.8 ft suggested by A r i s t o v and K i s e l e v ( 1 0 5 ) f o r hydroxylated s i l i c a s and dehydroxylated s i l i c a s r e s p e c t i v e l y . -132-B.E.T. surface areas f o r vacuum d r i e d sheets were determined to be 0.510, 0..508. and 0.433 sq. m./g. f o r n i t r o g e n , argon and oxygen isotherms r e s p e c t i v e l y . These isotherms were not considered r e l i a b l e as the surface area of the samples was thought to be too small f o r r e l i a b l e r e s u l t s on the volumetric device. However, the agreement between the n i t r o g e n isotherm B.E.T. surface area and the B.E.T. surface area determined on the continuous flow device (which i s de-signed f o r areas of t h i s magnitude) i s q u i t e good, 0.510 and 0.493 sq.m./g. r e s p e c t i v e l y . The e f f e c t of beating on the surface area of wood pulp as measured by solvent exchange d r y i n g and n i t r o g e n ad-s o r p t i o n i s shown i n t a b l e 15 and f i g u r e 4 l . Also shown i n f i g u r e 4l i s s i m i l a r data of Stone and S c a l l a n (16). The surface area decrease with beating found i n t h i s work i s contrary to the tre n d found by Stone and S c a l l a n (16) and by Thode et a l (54) (see t a b l e 6). However, Grotjahn and Hess (49) u s i n g argon as the adsorbate found no s i g n i f i c a n t change i n surface area (see t a b l e 4). No s a t i s f a c t o r y e x p l a n a t i o n has been found f o r t h i s d i f f e r e n c e other than the pulps used were q u i t e d i f f e r e n t unless one assumes the solvent exchange d r y i n g c o l l a p s e s pores r e s u l t i n g i n surface area l o s s . The pulps used i n the various s t u d i e s were q u i t e d i f f e r e n t as a commercial, f u l l y bleached k r a f t pulp which was p r i m a r i l y Douglas f i r and western hemlock was used i n t h i s work while Stone and S c a l l a n used a bleached spruce s u l p h i t e pulp and Thode et a l used a commercial western hemlock s u l p h i t e pulp. Grotjahn and Hess d i d not s p e c i f y the type of pulp -133-i i i • DRIED AT 105 °C • DRIED AT 105°C FOLLOWED BY HEAT TREATMENT AT 150* C • THIS WORK, NEVER DRIED 10 1 1 ' 1 i i i — 1000 2000 3000 4000 5000 6000 REV [P.F.I. MILL] FIGURE 41: THE EFFECT OF BEATING ON THE SOLVENT EXCHANGE DRIED B.E.T. SURFACE AREA -134-used I n t h e i r e x p e r i m e n t s o t h e r t h a n t o g i v e the name, M'odocord. Stone and S c a l l a n (60) have r e p o r t e d s i g n i f i c a n t d i f f e r e n c e s i n the b e h a v i o r o f k r a f t and s u l p h i t e p u l p s w i t h s o l v e n t exchange d r i e d samples. The machines used t o beat t h e p u l p s were d i f f e r e n t ; Stone and S c a l l a n and t h i s work used P.P.I, m i l l s , Thode e t a l used a b a l l m i l l and G r o t j a h n and Hess used a S t r e c k e r - M u h l e Model DKM 00 machine. The ranges o f t h e measured s u r f a c e a r e a s o f b e a t e n n e v e r d r i e d p u l p s as d e t e r m i n e d by t h e v a r i o u s w o r kers are summarized I n t a b l e 17. ' T a b l e 17: Ranges o f B.E.T. Areas on Beaten Samples Workers Thode e t a l Stone and S c a l l a n G r o t j a h n and Hess T h i s work B.E.T. Areas (sq.m./g.) Unbeaten p u l p H e a v i e s t b e a t e n range p u l p 100 130 184* 193 202 170 195 161 100 - 202 130 - 170 178 - 207 158 - 193 I n t e r e s t i n g l y , b o t h t h e Thode e t a l and t h e Stone and S c a l l a n s u r f a c e a r e a s f o r unbeaten p u l p are c o n s i d e r a b l e l e s s t h a n t h e l o w e s t s u r f a c e a r e a r e p o r t e d by G r o t j a h n and Hess o r d e t e r m i n e d i n t h i s work. I f some o f the pore s t r u c t u r e c o l l a p s e d d u r i n g s o l v e n t - exchange d r y i n g , as i t a p p a r e n t l y does * b e a t e n s l i g h t l y -135-because of the large discrepancy between the pore volume as determined by a c c e s s i b i l i t y and gas a d s o r p t i o n , one may w e l l expect pulps prepared by d i f f e r e n t chemical treatment to c o l l a p s e d i f f e r i n g amounts. This may be the reason the unbeaten k r a f t pulp of t h i s study has a s i g n i f i c a n t l y higher B.E.T. surface area than the s u l p h i t e pulps of Thode et a l and Stone and S c a l l a n . A f t e r moderate b e a t i n g , the surface areas of the d i f f e r e n t pulps have comparable surface areas. Figure 42 shows the change i n area w i t h moisture content p r i o r to solvent exchange d r y i n g f o r t h i s work and that of Stone and S c a l l a n (16). In order to have a d i r e c t comparison, the surface areas are reduced to a common ba s i s by d i v i d i n g the experimental areas by the area found f o r the solvent exchange d r i e d f u l l y water swollen pulp. Table 18 l i s t s these data. As there i s a reasonable agreement between the two sets of data, the conclusions of Stone and S c a l l a n (16) are s u b s t a n t i a t e d . The c o n c l u s i o n i s that very l i t t l e happens on d r y i n g from high moisture contents u n t i l about equal parts water and f i b r e are reached. At t h i s p o i n t , the pore volume, and hence the surface area, s t a r t s to decrease and continues to decrease to zero moisture, at which point the pore volume has been reduced v i r t u a l l y to zero. Lyne and G a l l a y (33) i n t h e i r s t u d i e s on the development of t e n s i l e s t r e n g t h i n a wet web found the t e n s i l e s t r e n g t h began to develop s i g n i f i c a n t l y at about 50 percent s o l i d s (equal p a r t s water and s o l i d s ) . Thus i t would appear the onset of s i g n i f i c a n t - 1 3 6 -PERCENT MOISTURE -137-Table 18: Dependence of Surface Area on Moisture Content. Percent Moisture Area (sq.m./g) Area  Area of Saturated Sample Stone & S c a l l a n (20) 95 93 1.0 64 93 1.0 47 89 0.96 42 65 0.70 28 51 0.55 24 51 0.55 13 24 0.26 4 7 0.075 0 1 0.01 This work saturated 193-2 1.0 33.6 122.7 0.646 14.4 22.3 0.115 5-3 7.31 0.038 0 5.17 0.027 -138-t e n s i l e s t r e n g t h i n a wet web i s accompanied by a d e c r e a s e i n the pore volume. C. Pore A n a l y s i s The pore volume and pore a r e a d i s t r i b u t i o n s a re s i g n i f i c a n t l y a f f e c t e d by t h e g e o m e t r i c model assumed. T h i s i s shown i n f i g u r e s 43 and 44. T h i s e f f e c t was d i s c u s s e d i n s e c t i o n IV-C. However, as the d i f f e r e n c e s i n the pore volume and pore a r e a d i s t r i b u t i o n s i n f i g u r e s 43 and 44 are due t o c a l c u ] a t i o n a l d i f f e r e n c e s , t h e e f f e c t s o f p h y s i c a l p a r a m e t e r s , such as b e a t i n g , on the pore volume and pore a r e a d i s -t r i b u t i o n s w i l l be s i m i l a r f o r t h e two models. Throughout the f o l l o w i n g d i s c u s s i o n , t h e pore shape has been assumed t o be t h a t o f a p a r a l l e l s i d e d f i s s u r e u n l e s s o t h e r w i s e n o t e d . The c a l c u l a t i o n method o f P i e r c e (48) was m o d i f i e d t o be a p p l i c a b l e t o t h e p a r a l l e l s i d e d f i s s u r e model and t h i s m o d i f i e d method was used f o r a l l n i t r o g e n d e s o r p t i o n i s o -therms. The v a l u e s o f the c u m u l a t i v e pore volume and cumu-l a t i v e pore a r e a are a f f e c t e d by the r e l a t i v e p r e s s u r e at w h i c h t h e c a l c u l a t i o n begins.- T a b l e 19 i s a comparison o f t h e v a l u e s o f t h e s e v a r i a b l e s d e t e r m i n e d from a n i t r o g e n de-s o r p t i o n i s o t h e r m o f s o l v e n t exchange d r i e d unbeaten wood p u l p u s i n g two d i f f e r e n t v a l u e s o f r e l a t i v e p r e s s u r e at t h e b e g i n n i n g o f t h e c a l c u l a t i o n . T a b l e 19 shows t h a t by c h a n g i n g the r e l a t i v e p r e s s u r e a t w h i c h t h e c a l c u l a t i o n b e g i n s from 0.90 t o 0.95, one changes t h e t o t a l pore volume from 150.3 t o I65.9 m i s . ( S . T . P . ) / g . . a n d a l s o changes t h e t o t a l pore a r e a from 122.3 t o 116.8 s q . m./g. These changes are m a i n l y due t o -138a-the d i f f e r e n t . s u r f a c e area assumed i n the c a l c u l a t i o n a l method when allowing f o r the volume of gas desorbed from the adsorbate adsdrbed on the exposed pore walls. Thus i f there i s s i g n i f i c a n t "external" surface area present (ie the area of open surfaces and of very large pores ) the c a l c u l a t i o n a l method does not allow f o r i t and the r e s u l t s are i n e r r o r . An error of 2.5 percent i n the i n i t i a l value of the adsorbed volume changes the pore volume from 150 .3 to 155.9 mis. (S.T.P. )/gm. and changes the t o t a l pore area from 122.3 to 123.8 sq.m./gm. Most of these changes are due d i r e c t l y to the error as evidenced by the small changes i n the data reported a f t e r the i n i t i a l p oint. These r e s u l t s i n d i c a t e that the pore volume c a l c u l a t i o n s are very s e n s i t i v e to changes i n the r e l a t i v e pressure of the i n i t i a l data point and to small errors i n the volume adsorbed. Thus , i n order to compare pore volume and pore area d i s t r i b u t i o n s , the adsorption volumes at s p e c i f i e d r e l a t i v e pressures were taken from isotherm p l o t s and used f o r the c a l c u l a t i o n s . Table I of Appendix D l i s t s the r e s u l t s of the pore analysis, on nitrogen WALL SEPARATION A 200 175 150 E 2 125 < UJ cc < LU 100 cc o o. LU < - J 2 o 50 25 15 -140-FIGURE 44 CUMULATIVE PORE AREA OF UNBEATEN SOLVENT EXCHANGE DRIED PULP AS DETERMINED BY NITROGEN a ARGON DESORPTION ISOTHERMS. O NITROGEN (PARALLEL SIDED FISSURE MODEL) A ARGON • NITROGEN (CYLINDRICAL PORE MODEL) 30 40 50 60 WALL SEPARATION A 150 200 Tabl-e 19: E f f e c t of I n i t i a l Data Point on Cumulative Pore Volume and Cumulative Pore Area High i n i t i a l r e l a t i v e pressure Lower i n i t i a l r e l a t i v e pressure E f f e c t of 2.5$ e r r o r i n i n i t i a l volume (P/P 0 = 0.95) (P/P D = = 0.90) ( v0.90 = 204.4) p/p 0 v , * ads. Area** Volume*** Area Volume Area Volume 0.950 225.2 0.900 199.4 5.66 30.2 0.850 181.0 12.3 50.9 7.51 23.4 9.55 29.7 0.800 164.1 20.5 69.4 16.7 44.2 18.7 50.3 0.750 149 .2 29.5 85-3 26.7 61.9 28.6 67.9 0.700 138.4 36.9 96.3 35.0 74.1 36.8 80.1 0.650 128.7 44.6 105.9 43.5 84.8 45.3 90.7 0.600 120.8 51.4 113-5 51.0 93.1 52.8 99.0 0.550 114.1 57.7 119.6 58.0 99.9 59.6 105.6 0.500 105.5 67.1 127.8 68.3 108.9 69-9 114.6 0.480 90.2 87.4 144.3 90.6 127.0 92.1 132.7 0.460 81.4 99.0 153.4 103-2 136.9 104.8 142.6 0.440 76.9 104.6 157.6 109-3 141.4 110.8 147.1 0.400 71.5 110.7 161.9 115.8 146.1 117.3 151.7 0.350 66.0 116.8 165-9 122.3 150.3 123.8 155.9 * V a d s = Volume adsorbed (mis. (S.T.P.)/g.) ** Area = Cumulative pore area (sq.m./g.) **'*-• "Volume = Cumulative pore volume (mis. (S.T.P. )/g.) - 1 4 2 -i s o t h e r m s . T a b l e 2 o f a p p e n d i x D l i s t s t h e s e c a l c u l a t i o n s u s i n g t h e e x p e r i m e n t a l d a t a p o i n t s . A l s o shown i n t a b l e 19 i s t h e e f f e c t o f a s m a l l e r r o r i n t h e v o l u m e a d s o r b e d a t t h e i n i t i a l p o i n t o f t h e c a l c u l a t i o n . A r g o n d e s o r p t i o n i s o t h e r m s were a l s o u s e d t o c a l c u l a t e t h e p o r e v o l u m e d i s t r i b u t i o n s a n d t y p i c a l r e s u l t s a r e shown i n f i g u r e s 43 and 44 . The p a r a l l e l s i d e d f i s s u r e m o d e l was a s s u m e d i n a l l p o r e a n a l y s i s u s i n g a r g o n d e s o r p t i o n i s o t h e r m s . The c a l c u l a t i o n t e c h n i q u e u s e d was s i m i l a r t o t h a t u s e d f o r t h e n i t r o g e n p o r e a n a l y s i s . As no d a t a f o r a r g o n a d s o r p t i o n on a n o n - p o r o u s c e l l u l o s i c m a t e r i a l a t 78 °K c o u l d be f o u n d o r d e t e r m i n e d e x p e r i m e n t a l l y on t h e a v a i l a b l e e q u i p m e n t , t h e i s o t h e r m r e p o r t e d by R h o d i n (165) f o r t h e a d s o r p t i o n o f a r g o n o n t o a s i n g l e c r y s t a l f a c e o f z i n c a t 78.1 °K was u s e d as a " s t a n d a r d " i s o t h e r m i n o r d e r t o e s t i m a t e t h e number o f m o n o l a y e r s a d s o r b e d o n t o t h e p o r e w a l l s . T h i s i s o t h e r m i s g i v e n i n T a b l e 1 o f A p p e n d i x F. A t h i c k n e s s o f 3-28 ft f o r a m o n o l a y e r o f a r g o n was d e t e r m i n e d f r o m t h e e x t r a p o l a t e d b u l k l i q u i d d e n s i t y u s i n g t h e m ethod p r o p o s e d by L i p p e n s , L i n s e n a n d de B o e r (110). The r e s u l t s o f t h e p o r e a n a l y s i s u s i n g a r g o n d e s o r p t i o n i s o t h e r m s w i t h s t a n d a r d i z e d r e l a t i v e p r e s s u r e s a r e l i s t e d i n T a b l e 3 o f A p p e n d i x D. T a b l e 4 , A p p e n d i x D, l i s t s t h e p o r e a n a l y s i s as c a l c u l a t e d f r o m t h e e x p e r i m e n t a l d a t a p o i n t s . The d i f f e r e n t i a l p o r e v o l u m e d i s t r i b u t i o n s o f t h e n i t r o g e n and a r g o n a n a l y s i s , a s s u m i n g t h e p a r a l l e l s i d e d -143-f l s s u r e model, are shown i n f i g u r e 45- The most common pore s i z e s shown i n f i g u r e s 43 and 45 are. 21 and 25 ft f o r argon and n i t r o g e n r e s p e c t i v e l y ( f o r p a r a l l e l sided f i s s u r e model). The cummulative pore volume d i s t r i b u t i o n s of a number of c e l l u l o s i c m a t e r i a l s are shown i n f i g u r e 46. These d i s t r i b u t i o n s , c a l c u l a t e d from ni t r o g e n desorption isotherms, were reduced to a common basis by d i v i d i n g by the t o t a l pore volume. The data of these samples are l i s t e d i n Appendix C. These samples and a l l of the ni t r o g e n isotherm samples i n t h i s work, show a most common pore s i z e of approximately 25 ft w a l l separation. • This has been i n t e r -preted as being a basic p h y s i c a l property of c e l l u l o s i c m a t e r i a l s ( 8 ) . The most common pore s i z e i s i n d i c a t e d by the point of steepest descent on the desorption isotherm. The average values of the most common pore s i z e as determined from the n i t r o g e n , argon and oxygen desorption isotherms on the samples used i n t h i s work were c a l c u l a t e d . These r e -s u l t s are given i n Table 20. As can be seen i n Table 20, f o r any of the ad-sorbates studied there i s very l i t t l e v a r i a t i o n i n the r e -l a t i v e pressure at which the most common pore s i z e i s found.. The dependence of the most common pore s i z e on the adsorbate used i s s i m i l a r to that noted by H a r r i s (149, 150) when he was studying microporous (Dubinin d e f i n i t i o n , S e c tion IV-D) s i l i c a s and aluminas of narrow pore s i z e d i s t r i b i t i o n . H a r r i s found that n i t r o g e n and argon desorption isotherms; on A (CUMULATIVE PORE VOLUME) A ( W A L L SEPARATION) fmls (SJ.R) -trtrl-_j ; 1 1 i i— ' • I I I 20 25 30 40 50 60 70 80 90 100 WALL SEPARATION A - 1 4 6 -Table 20: Pore Size at Steepest Descent on Desorption Isotherms Sample D e s c r i p t i o n Moisture Content (%) Saturated Saturated Saturated Saturated Saturated Saturated Saturated Vacuum d r i e d 5.3 1 4 . 4 33.6 Minutes Beaten 0 0 1 3 5 10 10 0 0 0 0 R e l a t i v e Pressure at Steepest Decent Nitrogen Argon Oxygen 0 . 4 8 0 . 4 9 0 . 4 8 0 . 4 8 0. 4 7 0 . 4 8 0 . 4 8 5 0 . 4 7 5 0 . 4 7 5 0 . 4 7 5 0 . 4 8 5 0.365 0.365 0.360 0.355 0.355 0.355 0.355 0.355 0.285 0.285 0.270 0.270 Average Values = Pore S i z e * C y l i n d r i c a l pore P a r a l l e l sided f i s s u r e pore 0.480 19-0 25.0 0.357 16.7 21.2 0.278 1 4 . 3 18.6 * The thickness of a monolayer was c a l c u l a t e d using the method of Lippens, Linsen and de Boer (110). The monolayer coverage f o r oxygen was., estimated by comparison of the oxygen isotherms with the ni t r o g e n isotherms. -147-these microporous samples, always i n d i c a t e d most common pore s i z e s of roughly 18 and 14 A radius r e s p e c t i v e l y (he assumed a c y l i n d r i c a l pore shape). Thus any micropores present i n solvent exchange d r i e d ' c e l l u l o s e would appear on the des o r p t i o n isotherm as pores of the most common pore s i z e . The apparently d i f f e r e n t values of the most common pore s i z e may w e l l be due to the e r r o r s i n assuming the K e l v i n equation i s a p p l i c a b l e , or i n assuming the number of monolayers adsorbed, or i n assuming the th i c k n e s s per monolayer or any combination of these assumptions. . The most common pore s i z e s as determined by n i t r o g e n , argon and oxygen isotherms r e f l e c t the same pa t t e r n as the molecular volumes of these adsorbates when the bulk l i q u i d d e n s i t y values are assumed (see t a b l e 2 1 ) . The cumulative pore volume d i s t r i b u t i o n s shown i n f i g u r e 43 are expressed as mis of gas at 0 °C and one a t -mosphere pressure, which i s simply a measure of the number of molecules r e q u i r e d to f i l l the pores. Some assumption must be made as to the volume occupied by a s i n g l e molecule of adsorbate. The adsorbate molecules are u s u a l l y assumed to r e t a i n the bulk l i q u i d p r o p e r t i e s and thus the volume occupied per molecule i s c a l c u l a t e d from the bulk l i q u i d d e n s i t y . Figure 47 i s the cumulative pore volume f o r the solvent ex-change d r i e d unbeaten pulp c a l c u l a t e d from n i t r o g e n and argon d e s o r p t i o n isotherms and assuming the l i q u i d d e n s i t i e s of the adsorbates. These data aF e l i s t e d i n Table 5 , Appendix D. Table 21 i s a comparison between the molecular volume c a l -c u l a t e d from bulk d e n s i t y and the van der Waals molecular volume (1 6 7 ) • 0.25 0.20 CO E £ <XI5 3 —I O > £ a i o o 0. Ul > < -J 3 3 O 0-05 O NITROGEN A ARGON X I FIGURE 47 CUMULATIVE PORE VOLUME EXPRESSED AS mis OF ADSORBATE IN BULK LIQUID FORM. CALCULATED FROM NITROGEN AND ARGON DESORPTION ISOTHERMS ON UNBEATEN S.E.D. PULP co l _L -L ± JL 20 25 30 35 40 WALL SEPARATION ( A* ) -L -L 50 60 70 80 90 100 -149-Table 21: Molecular Volumes of Adsorbates Adsorbates Molecular Volume cu. angstroms From de n s i t y van der Waals Nitrogen 57.8 25.0 Argon 45.6 20.6 Oxygen 44.6 23.0 The van der Waals molecular volume could be taken as the lower boundary f o r the p o s s i b l e volume of the adsorbate i n the pore. Thus Table 21 i s an i n d i c a t i o n of the wide range of mole-c u l a r volumes that could conceivably be used to convert the number of molecules i n the pores to an estimate of the volume of the pores. i s estimated the volume occupied by an adsorbate molecule i s assumed to be the volume occupied i n the bulk l i q u i d . This assumption of the bulk l i q u i d molecular volume i s a l s o used to c a l c u l a t e the t h i c k n e s s of the adsorbed l a y e r s on the pore w a l l s . A l l other workers surveyed (20, 46-48, 111-114) a l s o assumed the molecular volume of the'adsorbed adsorbate to be the same as that i n the bulk l i q u i d . Because of the higher energy of ads o r p t i o n of the f i r s t monolayer(20) the van der Waals molecular volume i s probably a b e t t e r estimate of the molecular volume than i s the bulk l i q u i d molecular volume.. However, a f t e r many l a y e r s , the adsorbate molecular volume must approach that found i n the bulk l i q u i d as a sharp t r a n s i t i o n to the bulk phase i s not probable. However, as the data r e q u i r e d to p r e d i c t the change i n molecular volume w i t h distance (or monolayers) from the adsorbent surface has not been found, i t was decided to-use the Throughout t h i s work where the a c t u a l pore volume - 149 a -bulk l i q u i d molecular volume. The cumulative pore volume d i s t r i b u t i o n s of f i g u r e s 47 and 48 show the two adsorbates p r e d i c t s i m i l a r a c t u a l pore volume d i s t r i b u t i o n s f o r pores greater than 30 ft w a l l s e p a r a t i o n , but p r e d i c t q u i t e d i f f e r e n t pore volume d i s -t r i b u t i o n s f o r pores of l e s s than 30 ft. This descrepancy i s due to the d i f f e r e n t values obtained f o r the most common pore s i z e . The d i f f e r e n t i a l pore volume d i s t r i b u t i o n of the vacuum d r i e d , solvent exchange d r i e d handsheets as c a l -c u l a t e d from argon and n i t r o g e n d e s o r p t i o n isotherms i s shown i s f i g u r e 49. The r e s u l t s shown i n f i g u r e 49 give a good i n d i c a t i o n of the apparently very l a r g e volume of pores at the most common pore s i z e . A comparison between the cumulative pore volume d i s t r i b u t i o n s of the vacuum d r i e d - solvent exchange d r i e d sample and the sample solvent, exchange d r i e d from a water suspension i s a v a i l a b l e i n fi g u r e . 5 2 . . WALL SEPARATION A -151-FIGURE 4 9 DIFFERENTIAL PORE VOLUME DISTRIBUTIONS OF SOLVENT EXCHANGE DRIED'VACUUM DRIED HANDSHEETS CALCULATED FROM NITROGEN AND ARGON ISOTHERMS. O NITROGEN A ARGON i ^ Q ^ ^ g F T A - Q r / r r Q i — t — A 3 0 40 50 60 80 100 WALL SEPARATION A -J A t -150 200 -152-The changes i n the cumulative pore volume d i s -t r i b u t i o n w i t h beating using n i t r o g e n and argon de s o r p t i o n isotherm pore a n a l y s i s are shown i n f i g u r e s 50 and 51- The s i g n i f i c a n t i n f o r m a t i o n contained i n these f i g u r e s i s the r e l a t i v e shape of the curves as the absolute value of these curves i s h i g h l y dependent on the f i r s t data poi n t as discusset above. There i s a much wider range i n the pore volumes c a l c u l a t e d by the argon based pore a n a l y s i s than f o r the n i t r o g e n based pore a n a l y s i s . No p h y s i c a l e x p l a n a t i o n f o r t h i s d i f f e r e n c e can be advanced. However, because of the a d d i t i o n a l assumptions i n c l u d e d i n the argon pore a n a l y s i s , the d i f f e r e n c e may be due to the method of c a l c u l a t i o n . Some of these a d d i t i o n a l assumptions are: i . The adsorbed argon i s assumed to be a supercooled l i q u i d w i t h p r o p e r t i e s e x t r a p o l a t e d from the l i q u i d argon r a t h e r than the s o l i d which bulk argon i s at the experimental temperature. The p h y s i c a l pro-p e r t i e s assumed are: surface t e n s i o n = 14.9 dyne/cm. dens i t y = 1.452 g./ml. i i . The isotherm of argon ad s o r p t i o n on single" c r y s t a l faces of z i n c (160). i s an appropriate, standard i s o -therm f o r c e l l u l o s i c m a t e r i a l s . o 0' 1 1 1 : 1—; 1 I l I l I 20 25 30 40 50 60 70 80 90 100 WALL SEPARATION I 150 125 \ ~ 100 a. • to 75-50 LU 2 3 _J O > UJ fltr LU p 25 < —i 3 3 O FIGURE 51 CUMULATIVE PORE VOLUME DISTRIBUTIONS OF SOLVENT EXCHANGE DRIED PULPS BEATEN VARYING AMOUNTS CALCULATED FROM ARGON DESORPTION ISOTHERMS. O UNBEATEN A BEATEN I MINUTE • BEATEN 3 MINUTES V BEATEN 5 MINUTES 9 BEATEN 10 MINUTES X JL I I 20 25 30 35 40 WALL SEPARATION & 50 60 70 80 90 100 -155-i i i . In s p i t e of the apparent disagreement with the B.E.T. areas, the c r o s s - s e c t i o n a l area of an adsorbed argon molecule i s 13-9 sq. A and t h i s assumption a l s o i s v a l i d f o r the th i c k n e s s of an argon monolayer. (The t h i c k n e s s of an argon monolayer i s assumed to be 3-28 ft) . The data presented i n f i g u r e 50 and Table 22 i n d i c a t e a s l i g h t s h i f t of the pore volume d i s t r i b u t i o n toward the l a r g e r pores as the degree of bea t i n g i s increa s e d . There i s a l o s s of t o t a l pore volume i n the pores of l e s s than 100 ft w a l l s e p a r a t i o n w i t h b e a t i n g . There i s a s i g n i f i c a n t l o s s of pore volume of the most common pore s i z e . The t o t a l pore volume and the volume of pores-of the most common pore s i z e are l i s t e d i n Table 23. The apparent l o s s of pore volume i n the most common pore s i z e may be i n t e r p r e t e d as i n d i c a t i n g the s t r u c t u r e of the f i b r e i s a l t e r e d even i n the very small pores. This e f f e c t would be expected i f a c e l l u l o s e f i b r e were constructed of t h i n laminar sheets with s l i t shaped pores be-tween the sheets, as t h i s type of s t r u c t u r e would have l i t t l e p h y s i c a l r e s i s t a n c e to the laminar sheets being separated by the mechanical a c t i o n of the beater. Table 23 a l s o presents an i n t e r e s t i n g comparison between the volume of a monolayer (B.E.T.), the volume of pores detected at the most common pore s i z e and the Dubinin micro-pore volume (from S e c t i o n VI-E) . Table. 23 shows that the change w i t h b e a t i n g of the volume of the most common pore s i z e i s grea t e r than the change of the B. E. T. monolayer volume. The -156-T a b l e 2 2 : Pore Volume o f D i f f e r e n t S i z e d Pores Sample D e s c r i p t i o n P e r c e n t o f T o t a l Pore Volume D e t e c t e d i n Pores o f W a l l S e p a r a t i o n M i n u t e s M o i s t u r e Less t h a n 39.1- G r e a t e r t h a n Beaten Content 39.1 a 96.5 a 96.5 ft P e r c e n t P arameter: L e v e l o f B e a t i n g ( e x p r e s s e d as m i n u t e s ) 0 S a t u r a t e d 43.6 40.9 15-5 1 S a t u r a t e d 43-3 34.4 22.3 3 S a t u r a t e d 34.2 40.6 25.2 5 S a t u r a t e d 36.1 37 - 8 26.1 10 S a t u r a t e d 35.7 39.3 25.0 Parameter: P e r c e n t M o i s t u r e Content P r i o r t o S o l v e n t Exchange D r y i n g 0 Vacuum d r i e d 71.2 18.2 10.6 0 . 5.3 79.3 12.9 7.8 0 14.4 87.0 9.1 3.9 0 . 33.6 59.4 33.2 7.4 0 S a t u r a t e d 43.6 40.9 15.5 -157-change wi t h b e a t i n g of the c o r r e c t e d Dubinin micropore volume i s s i m i l a r to the change i n the B. E. T. monolayer volume. The e f f e c t of changing the moisture content of pulp sheets p r i o r to solvent exchange d r y i n g on the cumulative pore d i s t r i b u t i o n i s shown i n . f i g u r e 52 and t a b l e 22. The cumulative pore volumes of the samples have been "reduced" by d i v i d i n g by the t o t a l pore volume to enable d i r e c t comparisons to be made. These "reduced" values are l i s t e d i n Table 6 of Appendix D. From f i g u r e 52 and t a b l e 22 i t i s q u i t e apparent that the pore volume d i s t r i b u t i o n i s s h i f t e d toward the sm a l l e r pores as the moisture content i s lowered from s a t u r a t i o n . However, below some " c r i t i c a l " moisture content, f u r t h e r reductions i n moisture content s h i f t the,pore s i z e d i s t r i b u t i o n s l i g h t l y back toward l a r g e r pore s i z e s . This would imply that as d r y i n g progresses from the wet s t a t e , a l a r g e r p r o p o r t i o n of the pores of w a l l s e p a r a t i o n exceeding 30 A close than do pores of l e s s than 30 A w a l l s e p a r a t i o n . Below the " c r i t i c a l " moisture content when.most of the l a r g e r pores have c l o s e d , f u r t h e r pore c l o s u r e s must come from the pores of l e s s than 30 A w a l l s e p a r a t i o n . There i s the p o s s i b i l i t y that w i t h the p a r a l l e l s i d e d f i s s u r e model f o r pulp f i b r e s , the w a l l s of the l a r g e r pores move together form-in g s m a l l e r pores. This r e s u l t d i f f e r s from the r e s u l t s of Stone and S c a l l a n (16) on a s u l p h i t e spruce pulp. These workers found that the pore s i z e d i s t r i b u t i o n d i d not s h i f t during d r y i n g . Stone and S c a l l a n (16) c a l c u l a t e d t h e i r T a b l e 23: Comparison o f V a r i o u s C a l c u l a t e d Volumes* Sample Unbeaten B e a t e n 1 minute B e a t e n 3 m i n u t e s B e a t e n 5 m i n u t e s B e a t e n 10 m i n u t e s B.E.T. Monolayer Volume 45.38 41.75 38.65 36.22 36.99 C o r r e c t e d D u b i n i n M i c r o p o r e Volume 34 29 29 30 27 Volume o f Most Common Pore S i z e N i t r o g e n Argon 23.3-27.1 A 19.5-21.8 ft 32.5 30.9 23.5 20.5 19.7 38.3 38.7 30.5 28.1 23.3 T o t a l Pore Volume N i t r o g e n Argon 150.5 138.2 146.2 112.1 117.1 161.2 132.7 126.0 93.2 107.8 * A l l volumes a r e e x p r e s s e d as m i s . ( S . T . P . ) / g . REDUCED CUMMULATIVE PORE VOLUME O — N > C M J> C R 0 t *>J 00 U > O m TI -651--160-median pore s i z e by equation 1 and found i t t o be constant at about 35 ft. This equation can be shown to i n d i c a t e e i t h e r the radius of a c y l i n d r i c a l pore or the w a l l separation of a p a r a l l e l sided f i s s u r e . The median pore s i z e c a l -c u l a t e d by equation 1 i s l i s t e d i n Table 24. The r e s u l t s l i s t e d i n Table 24 show the s h i f t of the median pore s i z e with d r y i n g . The r a p i d disappearance of the l a r g e r pore s t r u c t u r e s below 33.6$ moisture content corresponds with the r a p i d de-velopment of wet t e n s i l e strength as reported by Lyne and Gallay (33). Both of these r e s u l t s are probably due to the increased hydrogen bonding between c e l l u l o s e molecules. This hydrogen bonding probably r e s u l t s when the c e l l u l o s e mole-, cules of d i f f e r e n t s t r u c t u r a l elements of the f i b r e s (pore w a l l s , f i b r i l s etc.) are forced together by the high pressures r e s u l t i n g from the surface t e n s i o n of the water meniscus. • This mechanism was p o s t u l a t e d by Campbell (26,27,28) and elaborated by Barkas (32) as a means of e x p l a i n i n g how the f i b r e s t r u c t u r e c o l l a p s e s f o r i n t e r f i b r e bonding. With the . pressures developed by t h i s mechanism, d i s t o r t i o n s i n the c e l l u l o s e s t r u c t u r e would occur, thus a f f e c t i n g more than the s t r u c t u r e d i r e c t l y i n contact with the water meniscus. The cumulative pore areas of unbeaten solvent ex-change d r i e d pulp as determined by n i t r o g e n and argon de-s o r p t i o n isotherm pore a n a l y s i s are shown i n Figure 44. The molecular c r o s s - s e c t i o n a l area was assumed to be 13-9 and p 16.2 ft / molecule f o r argon and n i t r o g e n r e s p e c t i v e l y . The agreement between the two gases i s quite good f o r pores of -161-Table 24: Median Pore Sizes as Determined by Equation 1. Solvent Exchange Dried from Water Suspension Pulps unbeaten 36 beaten 1 minute 38* beaten 3 minutes 48 beaten 5 minutes 42* beaten 10 minutes 38* Solvent Exchange Dried Prom: water suspension 36 33.6 % water 32 14.4% water 21 5.3 % water 21 vacuum d r i e d 21 The isotherm was e x t r a p o l a t e d to p/p = O.965 -162-w a l l s e p a r a t i o n of greater than 30 ft, wit h the pore area determined by argon a n a l y s i s being l e s s than that determined by n i t r o g e n a n a l y s i s . The t o t a l pore area f o r the argon a n a l y s i s i s l a r g e r than, that found f o r the n i t r o g e n a n a l y s i s , whereas the argon B.E.T. surface area i s l e s s than that found f o r n i t r o g e n . The l a r g e r surface area f o r argon i s due i n part to the most common pore s i z e as determined by the argon a n a l y s i s being s i g n i f i c a n t l y l e s s than that found f o r the n i t r o g e n a n a l y s i s w i t h the r e s u l t i n g i n crease i n apparent surface area, f o r each u n i t of pore volume. The surface areas determined by the B.E.T. a n a l y s i s are compared to the t o t a l pore areas i n t a b l e 25. ' . ' The data of t a b l e 25 show that the B.E.T. surface areas f o r argon isothermsare c o n s i s t e n t l y l e s s thanthose f o r n i t r o g e n isotherms, while the pore areas determined from argon de s o r p t i o n isotherms are c o n s i s t e n t l y g reater than those determined from n i t r o g e n d e s o r p t i o n isotherms. The pore area i s always co n s i d e r a b l y l e s s than that determined by a B.E.T. a n a l y s i s , w i t h the l a r g e s t percent d i f f e r e n c e s o c c u r r i n g on sheets that were p a r t i a l l y d r i e d p r i o r to solvent exchange d r y i n g . According to P i e r c e (48) the B.E.T. and pore areas should agree to w i t h i n a few percent. However, i f there were a s i g n i f i c a n t . " e x t e r n a l " ( i . e . non-porous or larg e pored) surface area, the agreement between the two surface areas would be poor. Assuming there i s a s i g n i f i c a n t " e x t e r n a l " surface area, the d i f f e r e n c e between the pore area and the B.E.T. area should y i e l d a f i r s t estimate of t h i s " e x t e r n a l " area. The apparent change i n the d i s t r i b u t i o n of surface area below 33-6 percent Table 25: Comparison Between B.E.T. Surface Areas and Pore Areas Nitrogen Argon B.E.T. Pore Area A B.E.T. Pore Area p Q r e Sample D e s c r i p t i o n Area 9 6 . 7 ft B E T — A r e a 113-5 ft B E T ' A r e a sq.m,/g. sq.m./g. ' ' * sq.m./g. sq.m./g. Solvent Exchange d r i e d (S.E. D. ) :. Parameter: Minutes Beaten i n P.F.I. M i l l Unbeaten pulp 1 9 3 . 4 113 .7 0.588 1 7 7 . 4 1 4 5 . 6 0 . 8 2 1 Beaten 1 minute 1 8 2 . 0 113 .2 0.622 163 .5 125. 5 0 . 7 6 8 Beaten 3 minutes 168 .5 1 0 4 . 8 0.622 1 5 3 . 5 1 1 4 . 6 0 . 7 4 7 Beaten 5 minutes 157-8 8 8 . 6 0.561 1 4 3 . 2 92. 3 0 . 6 4 5 1 M C7\ Beaten 1 0 minutes 161. 3 8 3 . 0 - 0 . 5 1 5 1 4 3 . 2 92. 7 0 . 6 4 7 LAJ 1 Parameter: Percent Moisture P r i o r to Solvent Exchange Drying Vacuum d r i e d sheets 5 . 1 7 1 . 69 0.327 4 . 9 0 • 2 . 60 0 . 5 3 1 Sheets w i t h : 5 . 3 % moisture 7.31 2 . 9 8 0 . 4 0 8 7 . 2 0 " 3 . 9 5 0 , . 5 4 9 1 4 . 4 % moisture 2 2 . 3 8 . 6 0 . 3 8 6 3 3 . 6 % moisture 1 2 2 . 7 82 . 9 O.676 Saturated 1 9 3 . 4 1 1 3 . 7 0.588 177 .4 1 4 5 . 6 0 . 8 2 1 -164-m o i s t u r e i n d i c a t e s the pore a r e a l o s s due t o pore c o l l a p s e v/ith d r y i n g o c c u r s at a p r o p o r t i o n a l l y h i g h e r r a t e t h a n l o s s o f a r e a i n the " e x t e r n a l " s u r f a c e s . Emerton (168) s t a t e d t h a t b e a t i n g i n c r e a s e d the e x t e r n a l s u r f a c e a r e a . With the n i t r o g e n i s o t h e r m s , t h e r e i s no s i g n i f i c a n t change w i t h b e a t i n g . The argon i s o t h e r m s i n d i c a t e a change, but when one c o n s i d e r s the r e l i a b i l i t y o f the argon pore a n a l y s i s , i t I s not p o s s i b l e t o say t h e r e i s a s i g n i f i c a n t change. D. Pore Volume D i s t r i b u t i o n s as C a l c u l a t e d from A c c e s s i b i l i t y and Gas A d s o r p t i o n Data.  The a c c e s s i b i l i t y d a t a o f Stone and S c a l l a n (69) on b l a c k s pruce k r a f t p u l p o f 44.6 p e r c e n t y i e l d i s compared t o the c u m u l a t i v e pore volume o f the unbeaten s o l v e n t ex-change d r i e d p u l p o f t h e p r e s e n t s t u d y i n f i g u r e 53- Both c u r v e s are re d u c e d t o a t o t a l pore volume o f 1.0 T h i s r e d u c t i o n i s r e q u i r e d because the t o t a l pore volume o b t a i n e d from the a c c e s s i b i l i t y - d a t a i s a p p r o x i m a t e l y f i v e t i m e s the t o t a l pore volume o f the n i t r o g e n a d s o r p t i o n d a t a . A com-p a r i s o n o f t h e reduced d i f f e r e n t i a l pore volume w i t h pore s i z e i s shown i n f i g u r e 54. These two f i g u r e s show t h a t the l a r g e volume o f pores a t the most common pore s i z e , 35 A d i a m e t e r ( c y l i n d r i c a l p ores assumed) o r 25 A w a l l s e p a r a t i o n ( p a r a l l e l s i d e d f i s s u r e model assumed), i s not o b s e r v e d i n t h e a c c e s s -i b i l i t y d a t a . A l s o , t h e a c c e s s i b i l i t y d a t a do i n d i c a t e a s i g n i f i c a n t volume of' p o r e s below the most common pore' s i z e . The E i n s t e i n - S t o k e s ( o r S t o k e s ) e q u a t i o n ( e q u a t i o n 2) , w hich i s a b a s i c p a r t o f the a c c e s s i b i l i t y method, r e l a t e s PORE SIZE 1 1 ) T FIGURE 54 DIFFERENTIAL PORE VOLUME AS DETERMINED BY ACCESSIBILITY AND GAS ADSORPTION ACCESSIBILITY DATA ON BLACK SPRUCE KRAFT PULP OF 4 4 . 6 % YIELD O ACCESSIBILITY DATA OF STONE 8 SCALLAN A PARALLEL SIDED FISSURE MODEL (GAS ADSORPTION) • CYLINDRICAL PORE MODEL (GAS ADSORPTION) 9 10 •30 40 PORE SIZE 50 60 80 (* ) 100 150 200 300 -167-the diameter, of the solute, molecules, to the d i f f u s i o n c o e f f i c i e n t of the solute, i n the. solvent and the. v i s c o s i t y of the sol v e n t . I t i s v a l i d only f o r large molecules i n d i l u t e s o l u t i o n (169). The r e s t r i c t i o n of d i l u t e s o l u t i o n i s to e l i m i n a t e the i n t e r a c t i o n ( p o s s i b l y p h y s i c a l entangle-ment) between so l u t e molecules. The dextran and other mole-cules used by Stone and S c a l l a n (69) as molecular probes are polysaccharides as i s c e l l u l o s e (the glucose i s a mono-saccharide) (see Table 12). The s i t u a t i o n where the saccharide molecular probe molecules d i f f u s e i n t o pores of another saccharide ( c e l l u l o s e ) probably negates the assumption of d i l u t e s o l u t i o n as there l i k e l y w i l l be some i n t e r a c t i o n s between the sol u t e molecules and the s o l i d phase c e l l u l o s e molecules. Thus, i t i s doubtful i f the E i n s t e i n -Stokes equation i s a p p l i c a b l e f o r saccharides d i f f u s i n g i n t o pores of molecular proportions i n the c e l l u l o s e s t r u c t u r e . In a d d i t i o n , there i s evidence that the v i s c o s i t y of water i s increased when i n near contact with a s o l i d surface (170), thus changing one of the parameters of the Ei n s t e i n - S t o k e s equation. With the a c c e s s i b i l i t y c a l c u l a t i o n s , no allowance has been made f o r the water that i s adsorbed and p o s s i b l y hydrogen bonded to the w a l l s of the c e l l u l o s e pores. The surface area of the pores detected by the access-i b i l i t y method on the 44.6$ y i e l d k r a f t black spruce i s about 900-1000 sq.m./g. i f one assumes a p a r a l l e l sided f i s s u r e pore shape. This i s very large as the t o t a l surface area of a gram of i n d i v i d u a l c e l l u l o s e molecules i s estimated to be 1400 sq.m./g. (15). -168-A K e l v i n p o r e a n a l y s i s s u c h as t h e P i e r c e a n a l y s i s u s e d i n t h i s w o r k h a s many a s s u m p t i o n s a s s o c i a t e d w i t h i t . The p o s s i b l e s o u r c e s o f e r r o r a r e d i s c u s s e d i n s e c t i o n I V - C . T h u s , b e c a u s e o f t h e many s o u r c e s o f p r o b a b l e e r r o r , t h e c l o s e a g r e e m e n t f o r t h e a c c e s s i b i l i t y d a t a a n d t h e d a t a f r o m a P i e r c e a n a l y s i s o f a n i t r o g e n d e s o r p t i o n i s o t h e r m ( a s s u m i n g a p a r a l l e l s i d e d f i s s u r e p o r e s h a p e ) f o r p o r e s l a r g e r t h a n 30 A w a l l s e p a r a t i o n , may w e l l be f o r t u i t o u s a n d c a n n o t be u s e d as e v i d e n c e s u p p o r t i n g t h e p a r a l l e l s i d e d f i s s u r e m o d e l f o r p o r e s h a p e . B o t h f i g u r e s 53 a n d 54 i n d i c a t e t h e v e r y l a r g e v o l u m e o f p o r e s f o u n d by n i t r o g e n a d s o r p t i o n t e c h n i q u e s a t 25. A ( p a r a l l e l s i d e d f i s s u r e p o r e s h a p e ) a r e n o t d e t e c t e d by t h e a c c e s s i b i l i t y m e t h o d o f d e t e r m i n i n g p o r e v o l u m e d i s t r i b u t i o n . H a r r i s (149) ( S e c t i o n IV-H) f o u n d t h a t w i t h n i t r o g e n d e -s o r p t i o n i s o t h e r m s , p o r e s w i t h r a d i u s o f l e s s t h a n 18 A a p p e a r e d a s . i f t h e y were p o r e s o f 18 A r a d i u s . A c y l i n d r i c a l p o r e o f 18 ft r a d i u s i s e q u i v a l e n t t o a p a r a l l e l s i d e d f i s s u r e p o r e o f 25 ft w a l l s e p a r a t i o n . T h u s , i t i s p r o b a b l e t h a t p o r e s w i t h a w a l l s e p a r a t i o n o f l e s s t h a n 25 ft a p p e a r as 25 ft s i z e d p o r e s a n d t h e l a r g e v o l u m e o f p o r e s a t 25 ft w a l l s e p a r a t i o n do n o t e x i s t b u t a r e a r t i f a c t s o f t h e n i t r o g e n a d s o r p t i o n e x -p e r i m e n t a l t e c h n i q u e o f d e t e r m i n i n g p o r e v o l u m e d i s t r i b u t i o n s . - 168 a -E. D u b i n i n P o r e A n a l y s i s As t h e P i e r c e p o r e a n a l y s i s , t h e work o f H a r r i s e t a l an d t h e a c c e s s i b i l i t y d a t a o f S t o n e a nd S c a l l a n i n d i c a t e d s o l v e n t e x c h a n g e d r i e d c e l l u l o s e c o n t a i n s m i c r o p o r e s ( D u b i n i n d e f i n i t i o n ) t h e d e c i s i o n was made t o t r y t o d e t e r m i n e more a b o u t t h e s e m i c r o p o r e s . The D u b i n i n a n a l y s i s h a s b e e n p r o p o s e d as a m e t h o d o f m e a s u r i n g t h e v o l u m e o f m i c r o p o r e s i n a m i c r o p o r o u s s a m p l e . The D u b i n i n t h e o r y i s d i s c u s s e d i n s e c t i o n I V - P . A s e a r c h o f t h e l i t e r a t u r e i n d i c a t e d t h a t a D u b i n i n a n a l y s i s o f a s a m p l e s u c h as c e l l u l o s e h a d n o t b e e n a t t e m p t e d . D u b i n i n (133) s t a t e d t h a t i f t h e a r e a o f i n t e r m e d i a t e s i z e d p o r e s o f a s a m p l e i s a b o v e 50 sq.m./g. i t i s n e c e s s a r y t o c o r r e c t f o r t h i s s u r f a c e a r e a . The c o r r e c t e d a d s o r p t i o n v a l u e s a r e c a l c u l a t e d f r o m e q u a t i o n 15. The v a l u e o f a was t a k e n as t h e v / v o f t h e " s t a n d a r d " i s o t h e r m a t t h e r e l a t i v e p r e s s u r e m ^ o f t h e e x p e r i m e n t a l d a t u m p o i n t . T h i s i s l i s t e d i n t a b l e 2, a p p e n d i x P. The l o w e r l i m i t f o r t h e s i z e o f i n t e r m e d i a t e p o r e s i s a s s u m e d t o be where t h e K e l v i n t y p e p o r e a n a l y s i s a p p a r e n t l y b e g i n s t o b r e a k down, t h a t i s , a t t h e u p p e r l i m i t o f t h e most common p o r e s i z e , 25 ft w a l l s e p a r a t i o n o r 19 ft r a d i u s . -169-The P i e r c e pore a n a l y s i s o f t h e p r e c e e d i n g s e c t i o n i n d i c a t e s t h e s u r f a c e a r e a o f i n t e r m e d i a t e s i z e pores i s above 50 s q . m. /g. f o r some samples o f the s o l v e n t exchange d r i e d wood p u l p . E s t i m a t e s o f the s u r f a c e a r e a o f the i n t e r m e d i a t e s i z e d p o r e s f o r the samples used i n t h i s work a re t a k e n from the P i e r c e pore a n a l y s i s and are l i s t e d i n t a b l e 26. The " s t a n d a r d " i s o t h e r m used f o r the D u b i n i n p l o t c o r r e c t i o n s was t h a t o f Payne and S i n g (171) f o r n i t r o g e n a d s o r p t i o n on a l u m i n a s . T h i s " s t a n d a r d " i s o t h e r m r e p o r t e d v a l u e s o f r e l a t i v e p r e s s u r e t o 0.005 ( t h a t i s K o ( M ] 2 = 5.3) tp 11 A q u a d r a t i c e x t r a p o l a t i o n was used f o r e x p e r i m e n t a l p o i n t s w i t h a r e l a t i v e p r e s s u r e below 0.005. The " s t a n d a r d " i s o t h e r m i s l i s t e d i n T a b l e 2 o f Appendix F. S a t i s f a c t o r y " s t a n d a r d " i s o t h e r m s f o r n i t r o g e n , argon and oxygen on c e l l u l o s i c m a t e r i a l s were not found i n the l i t e r a t u r e . A t t empts t o de t e r m i n e such i s o t h e r m s by experiment on ra y o n ( a i r d r i e d ) and c e l l o b i o s e were u n s u c c e s s f u l . T a b l e 26 i n d i c a t e s t h e a r e a o f the i n t e r m e d i a t e s i z e p o r e s i s q u i t e s e n s i t i v e t o the shape assumed. The e f f e c t o f pore model on t h e c o r r e c t e d D u b i n i n p l o t i s shown i n F i g u r e 55-The d a t a p o i n t s f o r t h e c o r r e c t e d D u b i n i n p l o t s t o t h e r i g h t o f the v e r t i c a l dashed l i n e i n d i c a t i n g t he l i m i t o f " s t a n d a r d " i s o t h e r m v a l u e s a re c o r r e c t e d u s i n g an e x t r a p o l a t e d s t a n d a r d i s o t h e r m , and hence are p o s s i b l y i n c o n s i d e r a b l e e r r o r . F i g u r e 55 dees show t h e D u b i n i n a n a l y s i s t o be q u i t e s e n s i t i v e t o t h e -170-Table 26: Area of Pores Above 25.2 ft Wall Separation or 21.2 ft Diameter (Nitrogen Isotherms). Sample D e s c r i p t i o n Water Minutes Area Assuming Area Assuming Content Beaten P a r a l l e l C y l i n d r i c a l Sided F i s s u r e Pores Model sq.m./g. sq.m./g. Suspension 0 68, .1 116. .2 65. .1 110, ,0 Suspension 1 66. .5 • 85. • 3 Suspension 3 63". .7 98. .3 Suspension 5 '46. • 3 70, .3 Suspension 10 53. .7 87. , 2 Vacuum d r i e d 0 0. .42 0 . 66 5.3 0 0, .56 0. • 99 14.4 0 1. .024 2. . 06 33.6 0 36. .0 61. .5 FIGURE 55 EFFECT OF MODEL ON CORRECTED DUBININ PLOT LIMIT OF STANDARD ISOTHERM VALUES * EXTRAPOLATED CORRECTION VALUES UNCORRECTED PARALLEL SIDED FISSURE MODEL \ I CYLINDRICAL MODEL i i—1 8 10 (L06 l 0 (p*/p)) 2 12 14 16 -172-model assumed f o r the shape of the pores. The s e n s i t i v i t y of the Dubinin a n a l y s i s to e r r o r s i n the area of the i n t e r -mediate s i z e d pores i s shown i n Figure 56. Comparing Figure 56 to Figure 55 i t I s apparent that the e r r o r s introduced by e r r o r s i n the measurement of the surface area are small com-pared to those introduced by assuming an improper model. The n i t r o g e n adsorption isotherms on pulps of v a r y i n g moisture content p r i o r to solvent exchange d r y i n g were used i n c a l c u l a t i n g c o r r e c t e d Dubinin p l o t s . The p a r a l l e l sided f i s s u r e model was assumed. The r e s u l t s of these c a l c u l a t i o n s are shown i n Figure 57. The data p o i n t s using e x t r a p o l a t e d standard isotherm data have been omitted i n Figure 57. The c a l c u l a t e d data p o i n t s are l i s t e d i n Table 1 of Appendix G. The uncorrected Dubinin P l o t s of the same data are shown i n Figure 58. The i n t e r c e p t s determined from the data i n Figures 57 and 58 are given i n Table 27- The uncorrected Dubinin data p o i n t s are l i s t e d i n Table 2 of Appendix G. The data i n Table 27 i n d i c a t e that even f o r a sample w i t h a small surface area due to intermediate s i z e pores, the d i f f e r e n c e between the i n t e r c e p t s f o r c o r r e c t e d and un-c o r r e c t e d Dubinin p l o t s i s a s i g n i f i c a n t percentage of the value of the i n t e r c e p t . Thus f o r samples such as c e l l u l o s e , the c o r r e c t i o n f o r the area of the intermediate s i z e d pores must be a p p l i e d even f o r samples w i t h a s m a l l intermediate pore s i z e area. This f i n d i n g i s contrary to.the c o n c l u s i o n of Dubinin ( 133) who s t a t e d a c o r r e c t i o n was not r e q u i r e d i f the area of Intermediate s i z e d pores was l e s s than 50 sq.m./g. The s e n s i t i v i t y of the Dubinin p l o t i n t e r c e p t to the FIGURE 56 SENSITIVITY TO AREA OF PORES> 26 A SEPARATION UNBEATEN SAMPLE O ESTIMATED INTERMEDIATE PORE AREA O - 10 PERCENT + 10 PERCENT 6 8 10 (UOG | 0 (po/p)? 12 i M -J I (LOG ( P o /p) ) 2 IO FIGURE 58 DUBININ PLOTS OF NITROGEN ADSORPTION ISOTHERMS (UNCORRECTED) PERCENT MOISTURE PRIOR TO S.E. DRYING AS PARAMETER SATURATED 14.4% (LOGro(po/p)r VACUUM DRIED Table 27: Intercept Values f o r Corrected and Uncorrected Nitrogen Dubinin P l o t s with Moisture Content as Va r i a b l e Moisture Intercept l o g ^ x content of uncor-sample (%) rected corrected Saturated 1. 69 1.52 33.6 1. 45 1.33 14.4 0.75 0.72 5.3 0. 27 0.24 Vacuum Intercept mis. N 2 (S.T.P.) uncor-rected corrected d r i e d 0.10 0.06 49 28 5.6 1.86 1.26 33 21. 4 5.2 1.8 1.15 Intercept % Change Area of mis. l i q u i d N 2 f o r Intermediate uncor- C o r r e c t i o n s i z e pores re c t e d c o r r e c t e d 0.076 0.044 0.0087 0.0029 0.0020 0.051 0.033 0.0081 0.0028 0.0018 49 32 7.7 4.5 10 66.6 36.0 1.02 0. 56 0.42 i i— 1 — j I -177-c o r r e c t i o n f o r the area of the Intermediate pore s i z e i s l e s s f o r the samples p a r t i a l l y d r i e d p r i o r to solvent exchange d r y i n g . This r e f l e c t s the f i n d i n g of the pore a n a l y s i s of the preceeding s e c t i o n , where the pore volume d i s t r i b u t i o n s h i f t e d to s m a l l e r pore s i z e s w i t h d r y i n g . The microporous volume i s estimated assuming the bulk l i q u i d d e n s i t y a p p l i e s f o r the adsorbate molecules i n micropores. The e f f e c t s of b e a t i n g on the i n t e r c e p t of the c o r r e c t e d Dubinin p l o t are shown i n Table 28. Table 28: The E f f e c t of B e a t i n g on Corrected Dubinin A n a l y s i s Minutes beaten I n t e r c e p t Micropore Volume mis. l i q u i d N 2 mis.(S.T.P.)/g. 0 1.52 0.051 33 0 1.53 0.053 34 1 1.46 0.045 29 3 1.46 0.045 29 5 1.48 0.047 30 10 1.42 0.042 27 From the data of Table 28 and c o n s i d e r i n g the r e -l i a b i l i t y of the measurement, and assumptions i n v o l v e d , the con-c l u s i o n i s that the micropore volumes of the samples are very s i m i l a r , w i t h a s l i g h t t r e n d to lower volumes w i t h higher l e v e l s of b e a t i n g . The s i g n i f i c a n t c o n c l u s i o n i s t h a t there are apparently micropores present. Table 29: Uncorrected Dubinin P l o t Intercepts Sample Nitrogen Argon Oxygen Moisture Minutes —eontent Beaten log :10 x Volume Volume log ;io x Volume Volume l o g 1 Q x Volume Volume (%) gas* l i q u i d * * gas* l i q u i d * * gas* l i q u i d * * Saturated Unbeaten 1. 73 54. 0.084 1. 77 59. 0. 072 Saturated Unbeaten 1. 69 49. 0.076 1. 74 55. 0.068 1.78 60. 0.072 Saturated 1 1. 69 49. 0.076 1. 77 59- 0.072 1.78 60. 0.072 Saturated 3 1. 62 42. 0.065 1. 70 50. 0.062 1. 74 55. 0.066 ji —q Saturated 5 1. 62 42 0.065 1. 72 52. 0.064 CO 1 Saturated 10 1. 62 42. 0.065 1. 69 49- 0.060 Vacuum d r i e d Unbeaten 0. 10 1.26 0.0020 0. 18 1.5 0.0019 0.21 1.62 0.0019 5-3 Unbeaten 0. 27 1.86 0.0029 0. 39 2.5 0.0030 14.4 Unbeaten 0. 75 5.6 0.0087 33.6 Unbeaten 1. 45 28.2 0.044 * Volume of gas given as mis.(S.T.P.)/g. * Volume of l i q u i d adsorbate given as mi's./g. ( b u l k ' l i q u i d d e n s i t i e s assumed) -179-Uncorrected Dubinin p l o t s of n i t r o g e n , argon and oxygen adsorption isotherms on unbeaten pulp solvent exchange d r i e d from a water suspension are shown i n Figure 59. As the n i t r o g e n Dubinin p l o t has a smaller slope i n the l i n e a r p o r t i o n than do argon or oxygen, the e x t r a p o l a t i o n to determine the i n t e r c e p t should be more r e l i a b l e . The lower slope of the Dubinin p l o t i m p l i e s n i t r o g e n a d s o r p t i o n at low coverages i s more e n e r g e t i c than argon or oxygen adsorp t i o n . The higher a d s o r p t i o n values at low r e l a t i v e pressures i s d i r e c t evidence of t h i s . The e f f e c t of beating of the pulps on the uncorrected argon and oxygen ad s o r p t i o n Dubinin p l o t s i s s i m i l a r to that shown i n Figure 60 f o r n i t r o g e n a n a l y s i s . The i n t e r c e p t s of the uncorrected Dubinin p l o t s are given i n Table 29. Also given i n Table 29 are the e f f e c t s of solvent exchange d r y i n g of pulps from various moisture contents on the uncorrected Dubinin p l o t i n t e r c e p t s . The volumes t a b u l a t e d i n Tables 27, 28 and 29 r e -present the number of molecules r e q u i r e d to f i l l the micropores. To convert t h i s number of molecules to an estimate of the micro-porous volume r e q u i r e s the i n t r o d u c t i o n of a value f o r the volume occupied per molecule. Estimates of the volume of micropores assuming bulk l i q u i d d e n s i t y are given i n t a b l e 29-Table 21 gives an i n d i c a t i o n of the p o s s i b l e range of values that may be assumed. The data of Table 29 f o r microporous volumes, assuming bulk l i q u i d d e n s i t y i s a p p l i c a b l e i n the micropores, show very good agreement on a l l samples r e g a r d l e s s of the gas adsorbed. t 1.2-o o FIGURE 59 D U B I N I N P L O T S O F N I T R O G E N , A R G O N A N D O X Y G E N A D S O R B T I O N I S O T H E R M S O N S O L V E N T E X C H A N G E D R I E D U N B E A T E N P U L P o N I T R O G E N V A R G O N • O X Y G E N i i—1 oo o I < L 0 6 ( f t ( p o / p » ' 2 . 4 FIGURE 60 DUBININ PLOTS OF NITROGEN ADSORPTION ISOTHERMS WITH MINUTES PEL MILL BEATING AS PARAMETER 20 1.6 o UNBEATEN A I MIN. o 3 MIN. 9 5 MIN. V 10 MIN. 1 1—1 0 0 1—1 1 > 1.21 o o 0.8 o V A © v A o 0 . 4 J o 8 (L0G | O ( P < ,/p))2 10 12 14 16 -182-Whether t h i s agreement i s f o r the microporous volume or the surface area as proposed by the Kaganer theory (Section IV-G) i s unknown. At the present, the means are not a v a i l a b l e to determine which, i f e i t h e r , of the two options i s c o r r e c t . F. Kaganer Surface Area Determination According to Kaganer's theory (Section IV-G), the 2 i n t e r c e p t of the p l o t of l o g 1 Q x versus ( l o g 1 Q ( p Q / p ) ) (from equation 16) represents the adsorbate r e q u i r e d f o r a mono-la y e r coverage of the adsorbent. Table 31 has a comparison between the surface area determined by the B.E.T. method and the Kaganer method. The surface areas obtained form the Kaganer a n a l y s i s are s i g n i f i c a n t l y above those obtained from a B.E.T. a n a l y s i s . The agreement between the surface areas determined by the d i f f e r e n t adsorbates on the various samples i s s i g n i f i c a n t l y b e t t e r f o r the Kaganer a n a l y s i s than f o r the B.E.T. a n a l y s i s . The molecular c r o s s - s e c t i o n a l area was determined from equation 4 using the bulk l i q u i d d e n s i t y . The Kaganer surface areas r e f l e c t the same trends as the B.E.T. surface areas, G. C e l l u l o s e " t " - P l o t s The " t " - p l o t s proposed by de Boer and co-workers (110, 156, 158) compare the volume adsorbed onto the t e s t adsorbent to the volume adsorbed onto a non-porous "standard" at the same r e l a t i v e pressure. Thus i t i s necessary to have an isotherm on a non-porous adsorbent as a "standard". I t i s d e s i r a b l e to have the non-porous adsorbent chemically i d e n t i c a l to the porous t e s t m a t e r i a l . Several attempts were made to determine an - 1 8 3 -a d s o r p t l o n I s o t h e r m on a non-porous m a t e r i a l s i m i l a r t o c e l l u l o s e ( r a y o n , c e l l o b i o s e ) , but t h e s e f a i l e d t o produce an i s o t h e r m o f s u f f i c i e n t r e l i a b i l i t y . T h i s f a i l u r e was due t o the i n a b i l i t y o f the a d s o r p t i o n equipment t o measure the s m a l l a r e a s i n v o l v e d . Thus the d e c i s i o n was made t o use a n i t r o g e n a d s o r p t i o n i s o t h e r m on non-porous a l u m i n a as a s t a n d a r d i s o t h e r m . Two n i t r o g e n a d s o r p t i o n i s o t h e r m s on non-porous a l u m i n a are g i v e n i n the l i t e r a t u r e : L i p p e n s , L i n s e n and de Boer ( 1 1 0 ) ; and Payne and S i n g ( 1 7 1 ) . The s e n s i t i v i t y o f the " t " - p l o t t o the " s t a n d a r d " i s o t h e r m used i s shown i n f i g u r e 6 l . The s t a n d a r d i s o t h e r m p r oposed by P i e r c e (48) as a g e n e r a l i s o t h e r m i s a l s o i n c l u d e d . The t a b u l a t e d v a l u e s f o r t h i s c omparison are l i s t e d i n T a b l e 2 o f Appendix H. The s t a n d a r d i s o t h e r m s are g i v e n i n T a b l e 2 o f Appendix F. The " s t a n d a r d " i s o t h e r m o f Payne and S i n g was chosen f o r two r e a s o n s : t h e v a l u e s o f t h i s i s o t h e r m are v e r y s i m i l a r t o t h o s e o f the P i e r c e " s t a n d a r d " i s o t h e r m w h i c h has been used as a " s t a n d a r d " f o r a wide range o f m a t e r i a l s i n c l u d i n g c a r b o n , m e t a l s , o x i d e s and i o n i c c r y s t a l s , and, t h e i s o t h e r m i n c l u d e s a wide range o f r e l a t i v e p r e s s u r e s . I n a d d i t i o n , t h e s e w o r k e r s were aware t h a t t h e i r " s t a n d a r d " i s o t h e r m d i d not agree w i t h t h a t o f L i p p e n s , L i n s e n and de B o e r , and t h u s p r o b a b l y checked on t h e r e l i a b i l i t y o f the i s o t h e r m p r e s e n t e d . A l l o f t h e s e " s t a n d a r d " i s o t h e r m s r e s u l t i n a " t " - p l o t w hich i n d i c a t e s an a d s o r p t i o n f o r t h e porous c e l l u l o s e o f l e s s t h a n t h a t o b s e r v e d f o r t h e non-porous a d s o r b e n t . T h i s phenomenon c o u l d be due t o one o f t h e f o l l o w i n g : -184-FIGURE 61 Vvm FOR "STANDARD" ISOTHERM - 1 8 5 -(a) The "standard" isotherms given are not a p p l i c a b l e to c e l l u l o s i c m a t e r i a l s . (b) The monolayer c a p a c i t y as determined by the B.E.T. equation i s i n error. A lower value of the monolayer capacity would increase the v/v f o r the t e s t isotherm m perhaps by an amount s u f f i c i e n t to ensure that v/v^ f o r the t e s t isotherm was never l e s s than the corresponding value f o r the standard isotherm. The value of v m would have to be lowered by about 30 per-cent to accomplish the d e s i r e d e f f e c t . The " t " - p l o t s i n f i g u r e s 62 and 63 show the e f f e c t s of b eating and v a r y i n g moisture content on the solvent ex-change d r i e d pulps. The " t " - p l o t theory enables one to det e r -mine a surface area from the slope of the l i n e a r p o r t i o n of the p l o t . Table 30 r e s u l t s from such a determination. The sur-face areas as measured by the " t " - p l o t method are 30-40 percent l a r g e r than those measured by the B.E.T. technique. This f i n d i n g i s the reverse of what would be expected from the r e -s u l t s i n f i g u r e 6 l which r e q u i r e a smaller area to for c e ad-s o r p t i o n of the porous s o l i d to remain greater than that of the non-porous s o l i d . S t e r i c hindrance because of the r e s t r i c t e d a d s o r p t i o n space i n micropores would not account f o r the low B.E.T. suface area as these micropores would be f i l l e d before reaching the r e l a t i v e pressure at which the " t " - p l o t becomes l i n e a r (0.02< p/p Q< 0.45). In a d d i t i o n , the l i n e a r r e g i o n of the " t " - p l o t contains the range of a p p l i c a b i l i t y of the B.E.T. equation. One e x p l a n a t i o n f o r the high surface area measured by -186 --.187-T a b l e 30: S u r f a c e A r e a as Determined by " t " P l o t Technique Sample D e s c r i p t i o n M o i s t u r e Content p r i o r t o S.E.D. Minutes Beaten S l o p e I n t e r c e p t v m f r o m " t * P l o t . A r e a " t " P l o t Am= 0 16.2 A B.E.T. V m .B.E.T. Area S a t u r a t e d Unbeaten 60.2 59.8 -20.2 -19.5 60.2 .59.8 262 261 44.28 44.37 193.0 193.4 S a t u r a t e d 1 55.8 -17.4 55.8 243 41.75 182.0 S a t u r a t e d 3 51.9 -16.3 51.9 226 38.65 168.5 S a t u r a t e d 5 44.0 -8.9 44.0 198 36.22 157.9 S a t u r a t e d 10 51.2 -17.8 51.2 223 37.0 161.3 Vacuum d r i e d Unbeaten 1.66 -0.62 1.66 7.24 1.187 5.17 5.3 Unbeaten 2.25 -0.73 2.25 9.81 1.677 7.31 14.4 Unbeaten 7.02 -2.45 7.02 30.6 5.109 5.11 33.6 Unbeaten 39.7 . -14.7 39.7 . 173 , 28.147 28.15 the " t " - p l o t i s the a p p l i c a t i o n of the Payne and Sing (171) "standard" isotherm r e s u l t s i n se r i o u s e r r o r and i s not a p p l i c a b l e f o r • c e l l u l o s i c m a t e r i a l s . P i e r c e noted that i t i s p o s s i b l e that the v/v value c a l c u l a t e d f o r h i s standard isotherm, which m 5 i s very s i m i l a r to that of Payne and S i n g , may not be true on an absolute b a s i s , since they are r e l a t i v e to the volume assumed to f i l l the f i r s t l a y e r of each sample. Thus i f the v c a l c u l a t e d i s i n e r r o r , the whole standard isotherm i s In m ' e r r o r . Another p o s s i b l e e x p l a n a t i o n f o r the high surface areas as measured by the " t " - p l o t method i s that t h i s method i s not a p p l i c a b l e . One of the requirement of t h i s method i s that only surface l a y e r a d s o r p t i o n occurs without c a p i l l a r y condensation ( i . e . l o s s of pore area) throughout the l i n e a r p o r t i o n of the p l o t . Because of the wide d i s t r i b u t i o n of pore s i z e s apparently present i n c e l l u l o s e , i t i s p o s s i b l e that c a p i l l a r y condensation i s occurring i n some of the micropores or s m a l l e r t r a n s i t i o n a l pores throughout the l i n e a r p o r t i o n of the p l o t . With some pore s i z e d i s t r i b u t i o n s t h i s e f f e c t could i n d i c a t e an apparently high surface area. The range of l i n e a r " t " - p l o t s i s between r e l a t i v e pressures of 0.02 and 0 . 4 5 . Reduced " t " - p l o t s ( i . e . adsorption values d i v i d e d by the B.E.T. monolayer value) of a v a r i e t y of c e l l u l o s i c m a t e r i a l s are shown i n f i g u r e 64 . I t i s apparent, that over the pressure range of 0.02 to 0 . 4 5 these p l o t s may be described by a common equation. Thus, e i t h e r the p o r o s i t y of t h i s wide range of m a t e r i a l s i s i d e n t i c a l , or the "standard" isotherm i s i n e r r o r . -190-Q! I i I i i i 0 0.5 1.0 1,5 2.0 2.5 3.0 v/v "STANDARD" 0 0.01 OJ 0.25 0.50 0.75 P/Po Table 31: Comparison of Surface Areas C a l c u l a t e d by the Various Techniques ( a l l surface areas are expressed as sq.m./g.) Sample D e s c r i p t i o n Nitrogen Argon Oxy gen Moisture Content Minutes Beaten B.E. T. A = m Kaganer 16.2 Pore* Analysis . P l o t B.E. T. Am = 1 3 -Kaganer 9 Pore* A n a l y s i s A = m B.E.T. 12.5 Kaganer Saturated Unbeaten 193. 4 236. 261. 177. 4 221. Saturated Unbeaten 193. 0 214. 122.3 262. 170. 1 206. 151. 170.0 202. Saturated 1 182. 0 214 110.2 243. 163. 5 221. 132.2 164.5 202. Saturated 3 168. 5 183. 106.3 226. 153. 5 188. 116.7 153.5 185. Saturated 5 157. 8 183. 84.0 198. 143. 2 199. 93.3 Saturated 10 161. 3 183. 86.5 223. 143. 2 184. 98.9 Vacuum d r i e d Unbeaten 5. 17 5.5 1.79 7.2 4. 90 5.6 2.81 5.06 5.5 5.3 Unbeaten 7. 31 8.1 2.90 9.8 7. 20 9.4 4.48 14.4 Unbeaten 22. 3 24. 8.73 30.6 33.6 Unbeaten 122. 7 123. 83.8 173. I VO I * C a l c u l a t e d from normalized isotherms. -192-This a l s o i m p l i e s that over the pressure range of 0.02 to 0.45 the n i t r o g e n adsorption isotherms f o r t h i s wide range of c e l l u l o s i c m a t e r i a l s d i f f e r only as the B.E.T. monolayer value. H. Comparison of Surface Areas C a l c u l a t e d by the Various Techniques  While the pore a n a l y s i s value of the pore area i s r e s t r i c t e d to the area of the pores a c t u a l l y detected, the B.E.T., Kaganer and " t " - p l o t areas represent the t o t a l area of the sample a v a i l a b l e to the adsorbate molecules. The values reported by the various c a l c u l a t i o n a l methods f o r the t o t a l area of any given sample do not agree. While these methods (the B.E.T., Kaganer and " t " - p l o t ) a l l use the lower r e l a t i v e pressure end of the isotherm f o r t h e i r c a l c u l a t i o n s , the ranges of a p p l i c a b i l i t y are d i f f e r e n t : the B.E.T. a n a l y s i s i s v a l i d over the r e l a t i v e pressure range of 0.05 - 0.30; the Kaganer a n a l y s i s , 0.0 - 0.05; the " t " - p l o t a n a l y s i s , 0.02 - 0.45. The d i f f e r e n c e between the B.E.T. and Kaganer surface areas may be due to micropore f i l l i n g at very low r e l a t i v e pressures. The " t " - p l o t surface areas are considerably d i f f e r e n t from those determined by the B.E.T. a n a l y s i s , i m p l y i n g that one of the c a l c u l a t i o n a l techniques i s i n e r r o r as these methods u t i l i z e the same r e l a t i v e pressures. Because of the d i f f i c u l t i e s i n the a p p l i c a t i o n of the " t " - p l o t technique (described above i n s e c t i o n VI-G) one must assume the B.E.T. values are more c o r r e c t . A l l of the techniques f o r e s t i m a t i n g the surface areas of the pulp samples r e f l e c t the same trends w i t h changes i n the pr e p a r a t i o n of the sample although there i s a wide v a r i a t i o n i n the values assigned f o r any i n d i v i d u a l sample. The surface area - 192 a -as determined by the P i e r c e pore a n a l y s i s on n i t r o g e n isotherms r e f l e c t s s t r o n g l y the l o s s of pore volume wi t h d r y i n g as the area of the pore w a l l s decreases f a s t e r than the t o t a l surface area of the samples. Thus, while the a c t u a l value of the area a v a i l a b l e to an adsorbate molecule i s not known, the various methods of p r e d i c t i n g the surface areas do give reasonable parameters f o r c o r r e l a t i o n s . I. P h y s i c a l T e s t i n g of the Handsheets of the Experimental Pulps Some of the p h y s i c a l t e s t r e s u l t s on the handsheets of the t e s t pulps as a f u n c t i o n of beating time are l i s t e d i n Table 32 and shown i n Figure 65. Also l i s t e d i s the Canadian Standard Freeness of- the pulps. The B.E.T. surface area of the hand-sheets was determined by n i t r o g e n adsorption on the continuous flow a d s o r p t i o n apparatus. The dependance of some of the p h y s i c a l t e s t r e s u l t s of the handsheets and pulp on the B. E. T. surface area of the handsheets i s shown i n f i g u r e 66. The de n s i t y of the handsheets i s apparently a l i n e a r f u n c t i o n of the B. E. T. surface Table 32 : P h y s i c a l Test Results on Experimental Pulps Sample Unbeaten Canadian Standard Preeness (mis.) 728 B.E.T. Surface Area of Sheets 0 . 4 9 3 6 (sq.m./g.) 0 . 4 9 2 0 B a s i s weight of Sheets (g./sq.m.) 6 0 . 3 Moisture Content (%) 6 . 2 6 Density (g./cc) 0.516 Burst ( c o r r e c t e d to basis wt. = 60 g./sq.m.) ( l b . / s q . i n . ) 2 8 . 4 Number of Tests 13 95 % confidence l i m i t s O.98 Breaking Length (meters) 2960 S t r e t c h (%) Average 3 . 2 6 Maximum 3 •8 Minimum 3 •0 Tear Fa c t o r 5 9 - 0 Number of Sheets 20 Seaten . min. Beaten 3 min. Beaten 5 min. Beaten 10 min. 661 486 308 14 0 . 4 7 9 5 0 . 4 5 6 2 0. 4081 0 . 2 9 9 4 6 8 . 8 5 9 . 3 6 3 . 3 6 7 . 8 6 . 7 3 6 . 6 5 6 , 6 8 6 . 8 3 0 . 6 1 6 0 . 6 3 0 0. 674 0.741 41 . 1 5 8 . 0 6 6 . 1 7 0 . 3 12 12 12 12 2 . 3 0 2 . 6 3 1.91 5 . 3 5 4530 6200 6650 7100 3 -32 3 . 7 5 3 -80 * 3-9 4 . 1 4 . 2 2 . 9 3 . 3 3 . 5 3 2 . 0 1 8 . 8 1 6 . 0 1 3 - 0 20 25 25 20 * Some samples s l i p p e d i n the jaws l e a v i n g i n s u f f i c i e n t number f o r r e p o r t i n g - 1 9 4 -8 i FIGURE 65 PHYSICAL PROPERTIES OF HANDSHEETS AS FUNCTION OF TIME OF BEATING PULP. DENSITY a 10 (g./cc.) 6 4 3 TEAR FACTOR a to"' 2 4 6 M I N U T E S B E A T E N 8 10 -195-8 pIGURE 66 PHYSICAL PROPERTIES OF HANDSHEETS AS FUNCTION OF THE B.E.T. SURFACE AREA. 028 032 0.32 0.40 0.44 B.E.T. SURFACE A R E A (sq. m./g.) 0.48 0.52 a r e a a f t e r t h e i n i t i a l one minute o f b e a t i n g , w i t h the sheet d e n s i t y i n c r e a s i n g w i t h t h e d e c r e a s i n g s u r f a c e a r e a . An e s t i m a t e o f t h e a r e a o f the unbonded f i b r e s i s o b t a i n e d by e x t r a p o l a t i o n o f t h e b r e a k i n g l e n g t h o f t h e hand-s h e e t s back t o z e r o b r e a k i n g l e n g t h . T h i s e x t r a p o l a t i o n i s shown i n F i g u r e 66. The e s t i m a t e d unbonded s u r f a c e a r e a i s .52 sq.m./g. U s i n g t h i s v a l u e i t i s p o s s i b l e t o e s t i m a t e t h e bonded a r e a o f the handsheets i f one assumes the unbonded a r e a o f t h e p u l p s i s a c o n s t a n t v a l u e . The e s t i m a t e d bonded a r e a o f the v a r i o u s handsheets a re l i s t e d i n T a b l e 33-T a b l e 33: E s t i m a t e d Bonded Areas o f Handsheets Sample E s t i m a t e d bonded a r e a I n v e r s e o f e s t i m a t e d sq .m./g. bonded a r e a  0.025 40 0.038 26 0.063 16 0.110 9.1 0.219 4.6 I f t h e r e s u l t s o f p h y s i c a l t e s t s o f the handsheets were l i n e a r l y dependent on the e s t i m a t e d bonded a r e a , t h i s de-pendence would r e s u l t i n a l i n e a r p l o t i n F i g u r e 67. Thus t h e d e n s i t y o f the p u l p handsheets has an apparent l i n e a r dependence. on the bonded a r e a at h i g h e r bonded a r e a s . The r e s u l t s o f the b e a k i n g l e n g t h , b u r s t and t e a r f a c t o r t e s t s a r e p l o t t e d a g a i n s t t h e i n v e r s e o f t h e e s t i m a t e d bonded a r e a i n F i g u r e 68. The r e s u l t s o f F i g u r e 68 imply, t h a t t h e s e p h y s i c a l t e s t r e s u l t s a r e l i n e a r l y dependent on the i n -v e r s e o f the bonded a r e a . The v a l u e s o f t h e b r e a k i n g l e n g t h Unbeaten Beaten . f o r 1 minute Beaten f o r 3 minutes Beaten f o r 5 minutes Beaten f o r 10 minutes -197-80 70 60 50 3 0 -zo 10 6 FIGURE 67 DEPENDENCE OF PHYSICAL PROPERTIES OF HANDSHEETS ON ESTIMATED BONDED AREA. DENSITY HIO (cj./c.c.) BREAKING LENGH R i c T a (m.) BURST (Ib./sq.ln.) _L .05 .1 .15 .2 ESTIMATED BONDED AREA (sq.m/g). .25 -198-FIGURE 68 SOME PHYSICAL PROPERTIES AS FUNCTION OF THE INVERSE OF THE APPARENT BONDED AREA ~ 1 _l I J L . 0 10 20 30 40 I  APPARENT BONDED AREA -199-and b u r s t I n c r e a s e w i t h i n c r e a s i n g bonded a r e a whereas the t e a r f a c t o r d e c r e a s e s . I n a l l c a s e s , t h e e f f e c t o f an i n -c r e m e n t a l i n c r e a s e i n bonded a r e a i s l e s s where the t o t a l bonded a r e a i s l a r g e t h a n where the t o t a l bonded a r e a i s s m a l l . The d e c r e a s e i n the v a l u e o f t e a r f a c t o r w i t h i n -c r e a s i n g bonded a r e a i s a r e s u l t o f t h e s t r u c t u r e o f t h e sheet becoming more r i g i d and thus l e s s a b l e t o d i s p e r s e t h e h i g h l o c a l s t r e s s e s caused by the s h e a r i n g a c t i o n o f the t e a r t e s t e r . The i n c r e a s e i n the v a l u e s o f t h e b u r s t and b r e a k -i n g l e n g t h t e s t s w i t h i n c r e a s i n g bond a r e a i s i n t e r p r e t e d as b e i n g due t o the a b i l i t y o f t h e h i g h l y bonded s t r u c t u r e t o a v o i d t h e b u i l d up o f h i g h l o c a l s t r e s s e s , w h i c h would r e -s u l t i n a f a i l u r e o f t h e t e s t specimen. Ingmanson and Thode (85) r e p o r t e d r e s u l t s showing t h e dependence o f d e n s i t y , t e n s i l e s t r e n g t h and t e a r f a c t o r on the bonded a r e a e s t i m a t e d by a l i g h t s c a t t e r i n g t e c h n i q u e . T h e i r r e s u l t s show a s i m i l a r dependence on the e s t i m a t e d bonded a r e a as % the d a t a p r e s e n t e d i n F i g u r e 6 7 . A number of workers have p r e s e n t e d r e l a t i o n s h i p s between t h e t e n s i l e s t r e n g t h and t h e e s t i m a t e d bonded a r e a . Nordman and G u s t a f s s o n (82) u s i n g a l i g h t s c a t t e r i n g t e c h n i q u e found t h a t e x c e p t f o r samples s u b j e c t e d t o low wet p r e s s i n g p r e s s u r e s , l i t t l e o r v e r y heavy b e a t i n g , a l i n e a r r e l a t i o n s h i p e x i s t s between the t e n s i l e s t r e n g t h and bonded a r e a . Foreman ( 8 l ) , a l s o u s i n g a l i g h t s c a t t e r i n g t e c h n i q u e , o b t a i n e d a l i n e a r r e l a t i o n s h i p between the t e n s i l e s t r e n g t h and l o g ( b o n d e d a r e a ) o v e r a range of b e a t e r t r e a t m e n t s , e x c l u d i n g v e r y low and v e r y h e a v i l y b e a t e n p u l p s . Thus t h e r e i s a p p a r e n t l y l i t t l e agreement be-- 2 0 0 -tween the v a r i o u s workers on the e x a c t n a t u r e o f t h e r e l a t i o n -s h i p s between apparent bonded a r e a and p h y s i c a l t e s t r e s u l t s . T h i s l a c k o f agreement i s p r o b a b l y due t o the assumed un-bonded a r e a o f the samples and the range o f m a t e r i a l s used t o f u r n i s h the samples. -201-VII - CONCLUSIONS That micropores might be present i n solvent exchange d r i e d wood pulp was suggested by the work of H a r r i s (149) who noted that adsorbents having an average pore r a d i u s of l e s s than 18 ft always i n d i c a t e d an average K e l v i n pore ra d i u s of 18 ft. The co n c l u s i o n of t h i s work i s that solvent exchange d r i e d c e l l u l o s e contains micropores (Dubinin d e f i n i t i o n ) . This c o n c l u s i o n i s s u b s t a n t i a t e d by the P i e r c e pore a n a l y s i s , and by the Dubinin p l o t technique f o r the measurement of micropore volumes. The l a t t e r technique i n d i c a t e d that up to 70 percent of the t o t a l pore volume measured by gas adsor p t i o n would be i n the form of micropores. These are pores, whose rad i u s i s l e s s than 18 ft, i n which enhanced adsorption i s assumed to occur as opposed to the uniform a d s o r p t i o n assumed i n the B. E. T. a n a l y s i s . Thus the surface area c a l c u l a t e d by the B. E. T. method would be u n r e l i a b l e . While gas adso r p t i o n i s u s e f u l f o r e s t i m a t i n g the surface area and pore volume d i s t r i b u t i o n of s o l i d s which c o n t a i n only macropores and l a r g e r intermediate pores, i t i s not p a r t i c u l a r l y s a t i s f a c t o r y f o r use on adsorbents which c o n t a i n micropores such as solvent exchange d r i e d c e l l u l o s e . The f i g u r e s obtained i n such cases may be used to i n d i c a t e trends or as parameters to c o r r e l a t e some pulp or paper property against, but should not be used to measure the absolute s i z e of pores which are i n t u r n used to p o s t u l a t e models of the p h y s i c a l s t r u c t u r e of c e l l u l o s e of c e r t a i n dimensions. This -202-c o n c l u s i o n i s made because the c a l c u l a t i o n a l techniques used to evaluate the isotherms are of questionable v a l i d i t y and the solvent exchange d r y i n g technique apparently does not r e t a i n the s t r u c t u r e of the water swollen pulp. The c a l c u l a t i o n a l techniques f o r the determination of pore volume are i n doubt because a number of workers (38-40, 120-123, 127-129) have suggested that the p h y s i c a l p r o p e r t i e s of the l i q u i d adsorbate, which enter i n t o the K e l v i n equation, have d i f f e r e n t values i n bulk l i q u i d s than they do i n pores which are of a s i m i l a r order of magnitude i n s i z e to the . adsorbate molecules. Also the volume f i l l i n g of the pores wi t h adsorbate and the p o s s i b l e s t e r i c hinderance to entry of adsorbate molecules i n t o the micropores present are not allowed f o r i n the K e l v i n type pore a n a l y s i s . The Dubinin method of a n a l y s i s , w h i c h as f a r as i s known has not been used f o r c e l l u l o s e p r i o r to t h i s work, does consider the volume f i l l i n g of pores. .Gas adsorption techniques f o r determining the surface area of a i r d r i e d handsheets are apparently v a l i d as the volume of pores i n these samples i s so sm a l l that there i s almost no pore area to i n t e r f e r e w i t h the a p p l i c a t i o n of the gas a d s o r p t i o n c a l c u l a t i o n a l techniques. The lar g e volume of pores at approximately 18 ft r a d i u s or '25 ft w a l l s e p a r a t i o n detected by s e v e r a l workers using n i t r o g e n adsorption techniques p o s s i b l y do not e x i s t . This c o n c l u s i o n i s based on the r e s u l t s of H a r r i s (149) (described i n c o n c l u s i o n 2) and the a c c e s s i b i l i t y r e s u l t s of Stone and - 202 a -S c a l l a n which do not i n d i c a t e a l a r g e volume of pores at or near 18 - 25 ft w a l l s e p a r a t i o n . Thus the most common pore s i z e (18 ft radius or 25 ft w a l l separation) i s p o s s i b l y below the lower l i m i t of a p p l i c a b i l i t y of the K e l v i n equation and may not e x i s t . P. F. I . m i l l b e a t i n g of wood pulp a l t e r s the f i b r e s t r u c t u r a l components down to at l e a s t the l i m i t of a p p l i c -a b i l i t y of the K e l v i n equation as i s evidenced by the de-crease i n detected volume of pores at and below the most common, pore s i z e . Even wi t h pores of s i z e s l a r g e r than the most common pore s i z e , the pore volume d i s t r i b u t i o n s h i f t e d s l i g h t l y toward l a r g e r pores, a f i n d i n g contrary to the r e s u l t s of Stone and S c a l l a n , who found no s h i f t i n pore volume d i s t r i b u t i o n w i t h b e a t i n g . The surface area of the solvent exchange d r i e d pulps was found to decrease s l i g h t l y w i t h b e a t i n g , a f i n d i n g c o n t r a -d i c t o r y to the r e s u l t s reported by Stone and S c a l l a n (16) and Thode et a l (54). Grotjahn and Hess (49) reported no change w i t h b e a t i n g . The magnitude of the surface areas reported by the present work are s i m i l a r to those reported by Grotjahn and Hess and are s l i g h t l y l a r g e r than those r e p o r t e d by Stone and S c a l l a n and are cons i d e r a b l y l a r g e r than those reported by Thode et a l . The d i f f e r e n c e s are probably due to two f a c t o r s ; the solvent exchange d r y i n g technique, and the d i f f e r e n c e s i n the pulp samples used. - 202 b -Severe s t r u c t u r a l changes occur when wood pulp i s a i r -d r i e d from a water swollen s t a t e as i s evidenced by the decrease i n pore volume and the very pronounced s h i f t i n pore volume d i s t r i b u t i o n toward the sma l l e r pores. The s h i f t i n pore volume d i s t r i b u t i o n ( P i e r c e a n a l y s i s ) w i t h decreasing moisture content p r i o r to solvent exchange d r y i n g which i s so d e f i n i t e i n t h i s work i s contrary to the r e s u l t s of Stone and S c a l l a n (16), who reported there i s no s h i f t i n pore volume d i s t r i b u t i o n w i t h decreasing moisture content p r i o r to solvent exchange d r y i n g . No s a t i s f a c t o r y e x p l a i n a t i o n f o r t h i s discrepancy has been found other than the samples of wood pulp were q u i t e d i f f e r e n t . The B. E. T. surface area change wi t h decreasing moisture content p r i o r to solvent exchange d r y i n g found i n t h i s work agrees q u i t e w e l l w i t h the r e s u l t s reported by Stone and S c a l l a n (16) when the surface areas are reduced to a common b a s i s . (The B. E. T. surface areas f o r the p a r t i a l l y d r i e d samples were d i v i d e d by the B. E. T. surface area of the sample solvent exchange d r i e d from the wet s t a t e . ) While c e l l u l o s e pore s t r u c t u r e s are probably of complex shape, the p a r a l l e l sided f i s s u r e model proposed by Stone and S c a l l a n describes the r e s u l t s of t h i s work more adequately than the more commonly used c y l i n d r i c a l pore shape. - 202 c -" t " - P l o t s of n i t r o g e n adsorption isotherms on a wide v a r i e t y of c e l l u l o s i c m a t e r i a l s i n d i c a t e these isotherms could be described as a f u n c t i o n of the B. E. T. monolayer ca p a c i t y and the standard isotherm over the r e l a t i v e pressure range of 0.02 to 0.45. This i m p l i e s there i s no c a p i l l a r y condensation over t h i s pressure range. Future " t " - p l o t work should be based on a nonporous c e l l u l o s i c "standard" isotherm i n order t o e x t r a c t the maximum amount of i n f o r m a t i o n from t h i s promising method. -203-NOMENCLATURE A B. E. T. Surface Area A m Cross S e c t i o n a l Area of an Adsorbed Molecule (sq. ft) D D i f f u s i v i t y K, K 2 Constants M Molecular Weight of Adsorbate N Avagadro's Number o b R Gas Constant S Surface Area S„ Qg Surface Area Covered by a Monolayer of the Amount of Vapour Adsorbed at p/p Q = 0.08 T Temperature (°K) V Molar Volume Vmic Volume of Micropores i n Sample (mis.(S.T.P.)/g.) W Volume occupied by the Adsorbed Vapour c B. E. T. Constant k Constant C h a r a c t e r i z i n g the Gaussian D i s t r i b u t i o n of Surface P o t e n t i a l s Constant p Pressure of Adsorbate p S a t u r a t i o n Pressure of Adsorbate at Temperature of Adsorption p/p R e l a t i v e Pressure of Adsorbate r Radius of Pores (ft) K e l v i n Pore Radius (Radius of Void Space i n C y l i n d r i c a l Pore) r , Median Pore Radius med v Volume Adsorbed (mis.(S.T.P.)/g.) - 2 0 4 -v Q L i q u i d Volume of Vapour Adsorbed at p / p Q = 0 . 9 0 x Amount of Vapour Adsorbed per Gram o f Adsorbent x 0 9 6 5 L i c l u i d Volume o f Vapour Adsorbed at p / p Q = O . 9 6 5 x E x p e r i m e n t a l Value o f A d s o r p t i o n Where T r a n s i t i o n a l e Pores R e q u i r e C o r r e c t i o n f o r D u b i n i n A n a l y s i s x Amount of Ad s o r b a t e R e q u i r e d t o Form a Monolayer m a V a l u e o f Vapour A d s o r p t i o n f o r a U n i t S u r f a c e o f t h e Nonporous Adsorbent 3 A f f i n i t y C o e f f i c i e n t Y S u r f a c e T e n s i o n e A d s o r p t i o n P o t e n t i a l at the L i q u i d - V a p o u r I n t e r f a c e n V i s c o s i t y p D e n s i t y T K e l v i n W a l l S e p a r a t i o n ( D i s t a n c e Between Adsorbed F i l m s ) (j) C o n t a c t Angle / P a c k i n g F a c t o r -205-LITERATURE CITED 1. 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W., i n S t u f f P r e p a r a t i o n f o r Paper and Paper- board Making, ed. Bolam, F. M. , Pergamon Press, 1965 • 169. Longsworth, L. G., J . Am. Chem. S o c , 7_4, 4155-4159, (1952) 170. New S c i e n t i s t , 3_2, no. 5 1 8 , 176, (Oct. 27, 1966) 171. Payne, D. A. and Sing, K. S. W., Chem. and Ind., 918-919, (1969) 172. S c a l l a n , A. M., Personal Communication. -214-APPENDIX A ISOTHERMS ON UNBEATEN PULP—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION NITROGEN J L P. 0.00014 3.306 0.00082 8.566 0.00417 17.33 0.0125 25.70 0.0356 33.52 0.0533 . 37.14 0.0842 40.98 0.1315 45. B4 0.1749 49.63 0.2130 53.24 0.2523 56.58 0.2953 60.62 0.3390 64.62 0.40B2 71.77 0.4723 79.40 0.5387 88.12 0.6004 97.72 0.6698 110.84 0.7386 1*7.30 0.7094 141.19 0.8338 155.34 0.8812 176.09 0.9356 202.82 0.9701 228.82 0.9BB1 248.76 0.9602 231.34 0.9285 214.07 0.8823 193.76 0.8137 . 168.18 0.7597 151.68 0.68BO 135.01 0.6092 122.08 0.5584 115.33 0.5152 109.62 0.4957 102.83 0.4B39 93.14 0.4606 81.71 0.4237 74.75 0.3862 70.23 0.3544 66.60 0.4583 78.03 0.5580 91.81 6.6662 110.20 0.7597 133.19 0.8324 155.52 0.6898 179.86 0.75B9 148.01 0.62B6 123.91 ARGON p« 0.00440 7.577 0.0123 13.40 0.0253 21.32 0.0482 2B.79 0.0742 34.90 0. 1245 42.85 0.1535 46.80 0.1976 51.39 0.2314 55.42 0.3043 62.41 0.3490 67.59 0.3935 73.23 0.4513 86.84 0.5080 88.95 0.5606 97.45 0.6412 113.31 0.70S2 1Z7.37 0.7520 13B.65 6.8137 156.76 0.8697 174.09 0.9127 190.50 0.9395 202.13 0.9852 223.33 1.0000 236.60 0.9*6? 225.37 0.8986 206.21 0.8785 198.65 0.8318 183.57 0.7821 171.22 0.7185 157.70 6.6444 144.20 0.5807 134.01 0.5148 123.74 0.4615 115.98 0.4071 107.93 0.3762 101.23 0.36*6 91.64 0.3512 75.54 0.3045 63.04 0.2356 54.71 0.2984 61.53 0.3828 70.93 0.4764 82.5 r 0.5687 98.02 0.6631 116.82 0.7597 140.25 0.8644 170.67 0.9324 196.72 0.8710 113.36 0.8018 166.22 0.7307 152.72 0.6520 139.60 NITROGEN w p. 6.00423 14.25 0.0267 30.71 0.0356 33.51 0.0709 39.05 0.0933 41.66 0.1187 44.41 0.1621 4B.33 0.2155 53.33 0.2777 58.58 0.3275 63.63 0.3878 69.69 0.4736 79.57 0.5322 86.84 0.6257 101.73 0.7018 118.50 0.7733 136.71 0.8171 150.64 0.8979 187.59 6.9522 225.26 0.9716 246.49 0.9400 228.86 0.B753 195.65 0.7B2B 160.22 0.7107 139.46 0.6763 130.99 0.6306 123.62 0.5891 117.36 0.5392 110.54 0.4968 104.79 0.4872 99.30 0.4743 84 .15 0.455C 81.02 0.4266 75.57 0.3880 70.72 0.3553 67.02 ARGON p 0.0165 14.44 0.0352 22.87 0.0374 24.39 0.0788 34.57 0.0920 37.55 0.1279 41.64 0.1600 45.91 0.2374 53.38 0.3075 60.73 0.4300 74.30 0.4520 77.33 0.4947 83.39 0.5466 91.30 0.6256 104.82 0.6753 115.45 0.7155 123.85 0.7477 131.84 0.7967 145.64 0.8666 166.63 0.90B8 182.18 0.B6O6 173.05 0.B151 162.69 0.7530 150.21 0.7256 145.82 0.6557 133.93 0.5887 123.73 0.5598 119.61 0.5139 114.27 0.4442 105.06 • 0.4222 102.23 0.3756 95.85 0.3618 88.52 OXYGEN 0.0070 8.S79 0.0123 13.97 0.0376 26.21 0.0386 27.49 0.0877 38.71 0.09B9 41.35 0.2041 53.93 0.2449 59.40 0.2999 66.03 0.3584 74.21 0.4048 81.75 0.4702 93.21 0.5457 169.16 0.6112 125.35 0.7010 151.10 0.7596 172.92 0.8197 198.63 0.8696 224.83 0.9434 274.41 0.9814 305.35 0.9125 276.87 0.8867 261.93 0.0513 244.06 0.8235 230.41 0.7906 213.79 0.7248 188.30 0.6500 164.34 0.5689 144.36 0.4815 128.28 0.3995 115.15 0.3298 164.68 0.2863 85.09 0.2742 72.70 0.2459 59.82 0.1990 53.3S 0.1614 49.28 -215-ISOTHERMS ON PULP BEATEN I MINUTE—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION NITROGEN ARGON "~07CV<JiO6 0.00390 0.0191 0.0504 0.0785 0.1286 O.tTIT 0.Z222 0.2818 0.3426 0.4005 0.4648 0.5267 0.6258 0.T033 6.7778 0.6365 0.9484 0.3111 0.8660 0.8183 0.7540 0.6708 0.5622 8.966 13.69 27.72 34.62 36.43 43.23 47.06 51.11 55.97 61.5) 67.22 74.19 0.492T 0.4616 0.4361 0.3821 0.3149 81.03 94.53 110.78 128.21 144.77 206.51 189.04 166.97 132.02 136.21 121.93 110.86 97.94 86.48 71.41 64.69 50.65 0.0196 0.0367 0.0740 0.1359 0.1732 0.2267 0.2737 0.3120 0.3871 0.4473 0.5059 0.5815 0.6502 0.7121 0.7954 0.8654 0.9189 0.9632 6.9363 0.9264 0.8726 0.8328 0.7968 0.7237 14.05 23.83 34.36 41.80 46.16 51.24 55.45 99.49 67.46 74.44 62.26 93.04 103.64 117.47 136.69 194.80 172.34 196.12 113.IT 163.96 170.15 161.67 154.83 141.83 6.653V 132.26 0.5990 125.74 0.5426 118.74 0 .4865 111.63 0.4229 104.29 0.3849 99.17 G.34ed 9 3 . 5 * 0.3622 66.05 0 .3547 60.36 0 .3480 72.30 0 .3259 63.46 0.2910 36.08 0.247V 33.IT 0.0067 0.0209 0.0910 0.1026 0.1T50 0.2096 0.3059' 0.3675 .0.4612 0.5323 0.6131 0.6818 0.7982 0.8258 0.9054 0.9448 0.6842 0.6263 0.7550 0.6996 0.3493 0.4411 0.3306 0.2997 0.2691 0.2787 0.2637 0.2286 0.1643 8.931 17.80 29.28 39.19 48.90 53.83 64.16 72.64 86.80 100.49 116.16 137.26 159.73 184.03 223.99 254.73 225.68 199.71 173.79 153.11 134.24 119.63 107.55 97.41 —B6T53— 75.13 64.57 36.19 90.01 ISOTHERMS ON PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION W p. AI4SXR14 0.00046 6.36V 0.00164 11.12 0.0158 24.34 0.0210 26.23 0.0484 32.00 0.0771 35.92 0.1377 41.04 0.1883 45. 10 0.2491 49.91 0.3163 54.60 0.3909 61.31 0.4622 68.27 6.3261 76.64 0.3855 63.02 0.6406 92.21 0.7020 104.00 0.7543 115.67 0.6043 128.95 6.843* 142.42 0.8664 153.18 0.9173 200.84 0.9586 241.31 0.9154 201.65 0.8492 158.93 6.7783 134.21 0.6771 113.13 0.5884 99.93 0 . 5 4 4 7 " 94.77 0.4946 88.73 0.4719 76.86 6.4660 72.53 0.4269 66.61 0.3940 62.75 0.3394 39.57 P 0.00420 5.194 -U.0137 13.56 0.03B6 23.00 0.0933 33.49 0.1167 36.68 0.1845 43.38 0.2437 49.13 0.2891 52.89 0.3442 58.21 0.3891 63.17 0.4451 68.65 0.4968 74.81 0.5369 80.26 0.5733 85.50 0.6190 92.39 0.6903 104.77 0.7496 117.65 0.7952 128.73 6.8456 U 2 . i l 0.9196 163.00 0.9822 192.14 0.9228 174.61 0.8672 159.73 0.8383 152.38 0.7731 l i d . 3 2 0.7098 127.28 0.6519 118.57 0.6084 111.83 0.5479 104.22 0.4950 98.34 0.4391 93.32 0.4071 87.93 0.3697 83.44 0.3612 78.42 0.3544 71.17 0.3450 66.17 0.3222 38.94 0.2839 51.94 0.2389 49.69 P. "S mlttSXIA* 0.0151 12.94 ,0.0561 28.20 0.1049 36.01 0.1408 40.79 0.1699 44.63 0.2333 51.26 0.2860 57.45 0.3560 65.01 0.4273 74.71 0.9133 88.43 0.5850 103.45 0.6481 119.64 6.7217 139.12 0.7784 159.64 0.B351 184.07 0.8949 221.21 0.9244 250.51 0.96T4 310.59 0.9136 27b.ii 0.8776 240.62 0.8373 207.94 0.7761 178.42 0.6920 152.44 0.5968 130.73 6.4967 113.31 0.4037 99.52 0.3255 88.54 0.2806 78.53 0.2689 68.11 0.2510 58.56 0.2123 51.11 0.1680 45.65 ISOTHERMS ON PULP BEATEN 5 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION p "odi. P* 0.00032 6.493 0.00285 19.38 0.0119 23.49 0.0140 25.03 0.0310 29.B7 0.0668 34.38 0.1029 38.04 0.1519 41.08 0.2037 44.36 0.2625 47.89 0.3510 93.06 0.4292 98.54 0.4963 64.29 0.5692 71.56 0.6762 85.13 0.7566 98.12 0.8569 122.19 0.9177 152.20 6.9413 177.61 0.9028 154.30 0.8378 125.34 0.7286 102.93 0.6221 90.50 0.9333 83.60 6.4926 80.60 0.4669 69.86 .0.4389 62.16 0.4066 36.34 0.3724 55.60 0.2611 48.94 0.00400 0.0090 0.0236 0.048B 0.0898 0.1102 0.1456 0.1877 0.2451 0.3626 0.3639 0.4268 0.4774 0.5647 0.7023 0.7833 0.8670 . 0.9212 0.8730 0.7465 0.6804 • 0.5554 0.4719 0.3979 0.3493 0.33 86 0.3079 0.2716 0.2284 9.808 10.01 17.98 25.60 32.64 35.23 38.70 42.38 46.78 56.46 56.51 62.09 67.35 76.57 95.20 108.53 124.33 137.65 129.92 112.36 105.09 94.23 88.32 82.68 67.52 60.63 54.09 50.20 46.97 -216-; ISOTHERMS ON PULP K A T E N K> MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION [NJTROGEN : *i 0.2*40 0.1270 0.3951 41.54 50.81 54.92 0.4692 0.5449 1>.ftll2 , ,61.83 69.09 76.81 0 . 6 7 » 2 l 0.7*8* 0.8025 44 .56 97.81 109.21 0.6547 0.8975 " 0.9443 124.19 142.72 176.42 6.9845 0.9327 0,8339 1 0.7140 0.6649 0.6116 242.82 182.39 127.45 100.32 92.S3 06.46 0.5624 0.5073 0.4714 0.4383 0.3961 0.3594 81.38 75.63 64.78 59.52 55.96 53.11 ARGON "oft. • —^—izxtr i 0.00117 1 ' 0.00388 0,0084 . 0.0232 f 0.0307 0.0478 8 . 4 1 1 14.16 19.33 25.06 ~! 27.26 29.97 0.0715 0.0982 . 0.1533 0.1913 0.2329 0.2978 32.94 35.35 39.99 42.64 45.80 50.85 1 1 0.3431 ! 0.4090 0.4757 0.3417 ! 0.6352 0^7335 5 4 . 1 1 59.98 65.44 j 72.25 81.97 1 97.72 | 1 6.8099 | 0.8762 Q.9046 0.9585 0.9866 t 0.9481 1 1 4 . 7 2 134.13 1 144.80 187.97 228.67 191.31 j 1 0.8883 0.8239 i . 0.6914 0.6098 0.5605 0.5173 151.05 1 127.25 100.96 91.08 85.75 81.67 0.4735 1 0.4487 1 0.4207 0.3923 0.3576 69.44 64.37 60.92 58.09 55.19 OXYGEN • P i W 0.0134 0.0298 0.0629 0.1104 0.1381 0.1856 10.99 18.11 25.89 , 33.01 1 36.15 i 40.19 0.2177 0.2476 0.2947 0.3310 0.3619 0.3917 43.27 45.91 • 1 49.36 ' 52.70 55.61 58.4* 0 .4*57 0,5248 0.5861 6.6423 0.7145 0.7770 65.65 72.23 [ 80,37 J •8.90 100.52 112.64 0,8506 0.9460 . 0.8731 0.8314 0.7737. 0.7285 128.99 158.90 . 141.24 131.56 121.67 113.89 6.6661 0.6087 0.5617 0.5051 0.4546 0.4180 105 .69 98.25 93.08 86.95 | 82.35 • 78.54 0.3744 0.3607 0.3515 0.3398 0.3111 0.2700 74.13 69.32 64.83 58.42 53.04 48.15 ISOTHERMS ON UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE DRYING I NITROGEN A R G O N . OXYGEN i l P w P . •W ' -P. i 1 cw ' 0.00233 6.367 , 0.0182 0.421 0.0314 0.577 0.0136 0.670 | 0.0380 0.654 0.0654 . 0.847 0.0390 0.672 0.0741 0.879 0.1237 1.140 0.0578 0.974 0.0968 1,000 ' 0.1576 1.313 0.0971 1.084 . 0.1427 1.176 0.2388 1.611 0.1477 1.246 0.1972 1.352 0.2818 1.806 0.1903 1.339 0.2586 1.531 I 0.3231 1.969 0.2475 1.489 . . 0.2967 1.681 0.3835 2.222 0.3090 1.646 0.3544 1.859 0.4517 2.531 0.4078 1.890 0.4285 2.085 0.5142 2.802 6.4868 2.100 0.4923 2.322 0.6024 3.151 0.5620 2.312 0.5520 2.520 0.6B69 3.436 0.6422 2.524 0 . 6 U 5 2 .731 0.7643 3.A71 0.7645 2.768 0.7302 3.100 0.8422 3.911 . 0.8451 2.973 0.8162 3.333 0.8899 4.113 0.9197 3.247 0.8859 3.515 0.9473 4.626 0.9699 3.804 0.9453 3.664 0.8919 4.223 0.8868 3.177 0.9012 3.576 0.8127 3.94B 0.8243 3.613 0.8421 3.476 o.tui 3.7*8-0.7543 2.932 0.7703 3.380 0.6683 3.659 0.6B17 2.828 0.7095 3.299 - 1 0.5477 3.470 0.6110 2.804 0.6733 . 3.263 0.4652 3.343 0.560* 2.730 0.5992 3.150 0.3982 3.229 0.5169 2.686 0.5374 3.073 0.3538 3.124 0.4770 2.413 6.4742 2 .477 6.3671 . 2 . 44* . 0.4447 2.083 0.4352 2.885 0.2866 2.824 0.4047 ' 1.897 0.4154 2.663 0.2683 2.349 0.3680 1.809 0.3902 2.787 0.2621 2.150 0.3*39 2.6*6 0.2386 1.759 0.3551 2.446 0.2107 1.598 0.3472 2 . 2 2 * 6.1822 1.431 0.3361 2.049 0.3105 1.808 0.2655 1.565 ISOTHERMS ON UNBEATEN PULP SHEETS WITH 5 . 3 % MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING NITROGEN, ARGON P • P ' P. mltCSXfya. 0.00459 0.650 0.0159 0.534 0.0181 1.061 0.0277 0.861 0.0479 1.326 0.0788 1.408 0.0710 1.477 0.1004 1.576 0.1089 U 6 2 3 0.1705 1.920 0.1651 1.830 0.2302 2.202 0.2206 2.020 0.3248 2.620 0.2789 2.231 0.3926 2.951 0.3551 2.508 0.4339 3.178 0.4019 2.678 0.4833 3.450 0.4775 2.998 0.5510 3.810 0.5501 3.270 0.6101 4.124 0.62*9 3.566 0.6**1 4.445 0.6842 3.733 0.753* ' 4,830 0.7731 4,070 0.8677 5.286 0.8475 4.2*3 0.9380 5.54* 0.9086 4.505 0.9850 5.74* 0.9627 5.040 0.9288 5.575 0.9899 6.422 6 .8*2* 5.344 0.9586 5.158 0.7887 5.274 0.9022 4.740 0.7181 5.165 0.6405 4.546 0.6456 5.034 0.7648 4.429 0.5827 4.929 0.6715 4.310 0.5245 4.801 0.6656 4.204 6.4827 4.643 0.5400 4.107 0.4471 4.594 0.4952 3,774 0.4108 4.476 0.4694 3.356 0.3868 4,392 " 0.4372 2.894 0.3613 4.090 0.4041 2.677 0,3494 3.557 0.352* 2.470 0.33*1 3 .1** 0.2819 2.216 0.3207 2.645 ISOTHERM ON UNBEATEN PULP SHEETS WITH 14.4% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING NITROGEN P <w V 0.00053 0.786 0.00280 1.714 0.0109 2.761 0.O3O3 3.702 0.0623 4.297 0.0938 4.719 0.1386 5.245 0.1760 5.704 0.2203 6.157 0.2691 6.642 0.3427 7.531 0.4104 B.361 0.4?62 9.186 0.5586 10.30 0.6364 11.26 0.7185 12.23 0.7733 12.70 0.9197 13.61 0.973? 14.61 0.986? 15.77 0.9713 14.74 0.9126 14.06 0.8328 13.73 0.7640 13.58 0.6730 13.27 0.5960 13.04 0.5422 12.85 0.5036 12.23 0.4769 11.08 0.4578 9.643 0.4)40 9.661 0.3930 8.214 0.3439 7.559 0.2909 6.891 ISOTHERM ON UNBEATEN PULP SHEETS WITH 33JS>. MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING NITROGEN 0.00017 2.629 0.00057 5. 144 0.00200 8.850 0.006} 12.91 0.0132 16.41 .0.0294 19.92 0.0485 22.40 0.0667 23.81 0.0833 25.22 0.1002 26.46 0.1164 27.56 0.1610 30.27 0.1971 32.38 0.2313 34.38 0.2821 37.62 0.3752 44.01 0.4433 *9 .3 l 0.5397 58.15 0.6263 68.69 0.6972 78.14 0.7635 69.30 0.6208 99.82 0.8743 111.04 0.9699 127.47 0.9153 122.49 0.6356 114.33 0.7646 105.13 0.7119 98.13 0.6384 89.65 0.5753, 83.27 0.5312 78.96 0.4925 71.26 0.4802 62.78 0.4659 55.39 0.39T0 46.33 0.3474 42.62 0.27*1 37.70 ISOTHERMS ON VACUUM DRIED UNBEATEN PULP SHEETS NITROGENt mUBtBUt 0.0119 0.031 0.0326 0.050 0.0721 0.071 0.1144 0.098 0.1746 0.106 0.2321 0.132 0.2970 0.146 0.3960 0.152 0.4806 0.149 0.5620 0.162 0.6383 0.200 0.TO88 0.192 0.V7B2 0.225 0.6575 0.299 0.9457 0.452 0.9693 1.246 0.9434 0.436 0.8550 0.279 0.7744 0.264 0.7052 0.181 0.6452 0.20T 0.5366 0.181 0.4964 0. 164 0.4389 0.149 6.4214 6.176 0.3812 0.149 0.3470 0.149 ARGON 9_ w \ aUBXeVt 0.0380 0.022 0.0882 0.052 0.1229 0.093 0.1587 0.005 0.2091 0.116 0.2675 0.136 0.3021 6.147 0.3672 0.179 0.4350 0.196 0.3143 0.209 0.5897 0.224 0.6791 0.255 0.7509 6.282 0.8193 0.298 0.8882 0.336 0.9624 0.401 0.8671 0.331 0.8137 0.306 0.7464 6. 27* 0.6702 0.246 0.5607 . 0.210 0.9056 0.206 0.4645 0.165 0.4274 0.173 0.3920 6.168 0.3537 0.153 0.3217 0.140 0.2828 0.133 ISOTHERMS ON VACUUM DRIED UNBEATEN PULP SHEETS ARGON p p* 0.0326 0.025 0.0994 0.059 0.1409 0.091 0.1659 0.103 0.2463 0.121 0.3031 0.138 0.3598 0.143 0.4225 0.168 0.4964 0.166 0.5577 0.190 0.6290 0.213 0.6962 0.231 6.7388 6.243 0.8310 0.269 0.8677 0.289 1.0000 0.472 0.9416 0.331 0.8572 0.277 6.7712 6.556 0.7026 0.223 0.6620 0.203 0.59J5 0.164 0.3396 0.166 0.4775 0.139 6.4)16 6.136 0.3929 0.126 0.3715 0.129 0.3263 0.113 0.2906 0.102 OXYGEN _p PB 0.0353 0.018 0.0878 0.061 0.1332 0.092 0.2032 0.115 0.2316 0.123 0.2956 0.145 0.3462 0.161 0.4248 0.164 0.5138 0.215 0.5733 0.239 0.6472 0.256 0.7089 0.279 6.779* 0.287 0.8460 0.357 0.9078 0.455 0.9566 0.628 0.90T8 0.453 0.8423 0.363 0.7634 6.244 0.6956 0.263 0.6599 0.245 0.5641 0.211 0.4794 0.160 0.4344 0.195 6.3444 6.144 0.3727 0.147 0.3276 0.132 0.2761 0.114 -218-APPENDIX B SURFACE AREA OF HANDSHEETS (DYNAMIC ADSORPTION APPARATUS) UNBEATEN PULP SHEETS BEATEN I MINUTE t *adt. * P 0.053430 0.053430 0.053430 0.053360 0.053360 0.067 0.066 0.068 0.063 0.066 0.847509 0.853592 0.833600 0.690768 0.852410 0.189790 0.186770 0.187520 0.185670 0.1B7890 0.106 0.120 0.109 0.113 0.108 2.199994 1.912154 -2.108198 2.010244 2.141B3? 0.053360 0.053360 0.053360 0.151600 0.152560 0.152360 0.067 0.066 0.067 0.111 0.106 0.112 0.640348 0.652410 0.846336 1.613393 1.700981 1.609343 0.1B530O 0.120080 0.119730 0.119640 0.119610 0.118900 0.111 0.107 0.091 0.097 0.091 0.091 2.048686 1.279601 1.496749 1.409236 1.495044 1.475229 0.151980 0.237700 0.237700 0.237410 0.237410 0.236810 0.101 0.124 0.136 0.130 0.123 0.124 1.767324 2.507694 2.299938 2.402802 2.522943 2.495391 0.118190 0.043440 0.043080 0.042300 0.042340 0.042760 0.108 0.056 0.057 0.058 0.052 0.054 1.245746 0.817467 0.789671 0.757451 0.851009 0.816975 0.236810 0.236810 0.136 0.131 2.288655 2.377427 0.041630 0.041380 0.054 0.052 0.808115 0.826767 BEATEN J MINUTES BEATEN 3 MINUTES 0.053630 0.049 1.146685 0.053600 0.043 1.322493 0.053630 0.045 1.250279 0.053600 0.044 1.292776 0.053430 0.050 1.135677 0.053600 0.041 1.365663 0.053490 0.047 1.209163 0.053530 0.042 1.339922 0-049 1.156742 0.053530 0.04* 1 .316R86 0.053490 0.046 1.231485 0.053450 0.043 1.303601 0.053490 0.043 1.329677 0.053450 0.042 1.353592 0.053490 0.046 1.231485 0.053450 0.042 1.341718 0.152170 0.066 2.033788 0.152320 0.071 2.513229 0.152170 0.081 2.222233 0.152320 0.071 2.535046 0.131980 0.066 2.030793 0.152080 0.074 2.421052 0.151980 0.081 2.218962 0.152080 0.074 2.429124 0.151960 0.085 2.115412 0.151980 0.075 2.379646 0.151980 0.078 2.295200 0.151980 0.074 2.435357 0.236610 0.117 2.654011 0.236910 - 0.102 3.046921 0.236510 0.104 2.972732 > .0.236910 0.097 3.201587 0.236810 0.122 2.552290 0.236550 0.106 2.924307 0.236220 0.112 2.762107 0.236400 0.098 3.172429 0.236810 0.111 2.795828 0.236520 0.098 3.162575 0.236220 0.099 3.120160 0.236450 0.099 3.137699 BEATEN 10 MINUTES 0.180340 0.066 3.316299 0.185300 0.063 3.592431 0.182080 0.064 3.476602 0.185670 0.069 3.291343 ft-IROAAn 0.066 3.331671 '0.184400 0.064 3.522431 0.179650 0.068 3.220992 0.118660 0.056 2.392589 0.115580 0.047 2.758129 0.117620 0.047 2.859826 0.116590 . 0.044 3.007200 0.116540 0.048 2.775058 0.116930 0.053 2.479914 0.116080 0.045 2.964009 0.112340 0.057 2.212656 0.044460 0.028 1.686039 0.043580 0.032 1.427803 0.043490 0.028 1.6475B1 0.Q43080 0.030 1.497496 0.043080 0.027 1.659157 0.042760 0.037 1.214612 0.043000 0.027 1.637331 0.042300 -0.031 1.411285 APPENDIX C Table 1: ' N i t r o g e n Adsorption Isotherm Data of Hunt, B l a i n e and Rowen (18) A: A l k a l i Swollen Solvent Exchange Dried B: Sample A with 3.3% Water Sample A with 11.0% Water P/P Q 0. 018 0.090 0.131 0.203 0.250 0. 294 0.389 0.387 0.531 0.611 0.701 0.783 0.844 0.954 0.974 Volume* 10, 14, 16 18 20, 21.8 25.6 25.9 33.3 38.8 46.4 53.0 56. 2 61.0 62. 3 Desorption 0.823 0.665 0.527 0.494 0.493 0.475 0.363 0.2 45 -0.163 0.109 0.074 58.0 54.3 51.0 44.2 44.0 34.3 25.2 20.9 18.1 16. 3 15.0 D: C o n t r o l , Water Swollen, Solvent E: Outgased** C e l l u l o s e F i b r e s Rej ^ain Regain Exchange Dried P/P 0 Volume* p/p o Volume* P/P 0 Volume* P/P Q Volume* 0. 079 6.4 0.107 0.48 0.055 8.8 0. 081 0.14 0.126 7.1 0.146 0.53 0.084 9-7 0.152 0.15 0.190 8.1 0.191 0.54 0.159 11.5 0.194 0.17 0.245 8.9 0.261 0.62 0.207 12.5 0.249 0.19 0.302 9.8 0.355 0.64 0.256 13.6 0.283 0.19 0. 419 12.0 0.463 0.72 0.333 15.4 0.360 0.19 0. 616 18.1 0.562 0.79 0.525 20.0 0.516 0.17 0.718 23.0 0.678 0.97 0.654 22.8 0.692 0.25 0.716 23.1 0.832 1.90 0.806 25.4 ,0.813 0.41 . 0.826 28.5 0.923 3.83 0.786 25.8 0.928 0.66 0.959 34.0 0.872 27.1 Desorption 0.958 30.0 Desorption Desorption 0.819 2.59 Desorption 0.813 0.38 0.842 31.2 0.813 2.54 0.709 0.30 0.665 27.6 0.667 1.38 0.862 27.6 0.515 0.21 , 0.531 25-0 0.555 O.96 0.613 25.1 0.327 0.18 0.478 17.6 0.469 0.74 0.515 24.3 0.266 0.17 0. 340 10.5 0.413 0.68 0.475 22.4 0. 304 0.65 0.455 20.3 0.163 0.57 0.291 15.1 * Expressed as mis.(S.T .P.)/g. Adsorbed ** Not p l o t t e d on Figure 5 -220-APPENDIX C s Table 2:. Isotherm Data of Haselton (13) Nitrogen adsorption on benzene-dried specimens at -195.6 °C. r h l o r , f _ KOH-Extracted Sprucewood H o l o c e l l u l o s e . „ 1 C h l ? ^ " e H o l o c e l l u l o s e Volume Volume Volume p/p 0 Adsorbed* p/p o Adsorbed* P/P Q Adsorbed* 0. 014 0. 56 0.001 4.64 0.007 8.06 0.037 0. 71 0. 027 10.2 0.028 11. 0 0.075 0.84 0.083 13.0 0.078 13.6 0.126 0.96 0.140 14 .9 0.135 15.5 0.192 1.07 0.204 16.7 0.199 17.3 0.260 1.20 0.273 18.6 0.270 19.2. 0.328 1.31 0.. 340 20.6 0.339 21.2' 0.395 1. 41 0.410 22.9 0.409 23.5. 0.466 1. 54 0.484 25.7 0.482 26.3 0.540 1.73 0.551 • 28.5 0.551 29.2 0.608 1.93 0.616 31.3 0.615 32.4 0.679 2.12 0.683 34.1 0.678 35-9 0.750 2.36 0.751 36.8 0.739 39-7 0.817 2.64 0. 815 39.4 0. 801 43.8 0.882 3.11 0. 871 41.6 0.863 47.5 0.944 3.93 0.919 43.6 0.924 49.8 0.966 4.56 0.961 45.3 0.950 50.6 V s 46.9 V s 51.7 Desorption 0.921 3.79 0.910 43.9 0.892 49.6 0.853 3.20: 0.825 41.5 0.815 48.3 0.759 2.71 0. 746 39.1 0.737 45.8 0. 665 2.45 0.665 36.8 0.662 41.9 0.568 2.09 0.573 34.4 0.578 37.4 0.475 1.78 0.484 32.0 0.488 34.4 0.372 1.36 0.438 28.8 0.457 27.8 0.275 1.22 0.428 24.6 0.375 22.9 0.329 20.8 0.275 20. 0 0.230 17.9 0.181 17.2 0.137 15.2 * Expressed as mis.(S.T.P.)/g. -221-APPENDIX C Table 3: Isotherm Data of Merchant (12) Adsorption of Nitrogen on WAN-Dried F i b r e s * P/P, 901 804 713 558 487 474 449 408 267 Sample. E-37 WAN-Dried from n-Pentane Volume Adsorbed, ml.(S.T.P.)/g. 128.57 102.55 89.83 76.33 70.59 61.93 54.62 50.20 40. 72 Sample E-42 WAN-Dried from Cyclohexane P/P o Volume Adsorbed, ml.(S.T.P.)/g, .005 14.83 . 015 14.93 .061 26.89 .053 19.70 .122 31.45 .203 27. 49 .188 35.71 .476 41.13 .285 41.34 .607 49.80 .403 49.33 • 776 64.58 • 521 58.73 ' .887 81.22 .630 69-83 • 947 101.29 .751 86.11 • 972 121.61 .861 108.05 .924 . 131.45 .943 105.73 .957 154.34 .885 86.04 • 793 71.60 .870 • 117.97 .656 60.08 • 715 90.36 .551 54.68 .596 79-14 .503 52.48 • 513 72.92 .484 50.63 .444 53-91 .478 47.87 .342 45.51 .468 44.45 .225 38.26 .437 39.83 .384 36.22 :050 25.75 .245 29.48 .289 41.64 • 553 61.57 .114 23.51 • 759 87.63 .188 26.95 .833 100.93 .255 29.87 .912 126.02 .302 32.06 • 956 151.39 • 974 175.61 * WAN-Dried F i b r e s means f i b r e s d r i e d by solvent exchange. (WAN = Water-Alcohol-Nonpolar solvent) -222-APPENDIX C Table 3 Continued: P/P, Sample E-3 WAN-Dried from Benzene Volume Adsorbed ml.(S.T.P.)/g. Sample E-96, Water-Dried over P ^ J - J Water-Soaked 1 4 Days, WAN-Dried from n-Pentane P/P o Volume Adsorbed ml.(S.T.P.)/g. 090 9.92 . 0 0 6 6 . 5 0 1 6 3 11.49 . 0 5 0 1 0 . 7 5 264 13.26 . 1 2 1 1 3 . 0 5 3 2 0 1 4 .69 . 2 2 8 15.83 4 3 4 17.21 . 2 8 3 17.26 5 6 0 2 0 . 5 2 . 4 3 1 2 1 . 3 9 712 2 5 . 7 5 . 5 7 7 26. 71 8 8 2 3 5 - 3 6 . 7 0 3 32. 44 958 . 4 7 . 9 7 .874 42.65 9 8 1 6 1 . 9 5 • 970 54.06 . 9 9 6 66.64 9 1 1 4 1 . 5 1 7 6 6 3 0 . 9 1 . 9 6 4 5 7 . 9 0 666 2 7 . 5 3 . 8 4 8 4 5 . 8 6 601 2 5 . 8 9 .662 3 6 . 8 6 5 2 8 24.33 • 532 32.31 4 8 7 22.61 . 4 6 8 25.10 4 6 2 1 9 . 3 1 . 3 4 3 1 8 . 8 6 4 1 6 17.09 305 1 4 . 5 3 ' . . 0 2 2 9 : 0 1 203 1 2 . 4 8 .588 2 6 . 9 4 . 7 6 1 35.00 0 2 5 7.25 • 9 3 8 4 8 . 1 9 3 1 3 1 4 . 3 9 .988 59.81 6 0 5 2 1 . 7 2 811 30.08 . 9 6 0 55.00 929 41.25 .918 49.83 972 5 3 . 8 3 . 8 4 0 44.39 9 8 5 6 7 . 7 1 . 7 5 4 4 0 . 2 3 . 6 4 9 3 6 . 0 7 885 38.68 . 5 4 7 3 2 . 6 2 722 29-24 . 5 1 7 31.58 5 6 5 25.07 . 4 9 6 3 0 . 0 9 491 2 3 . 09 . 4 8 3 27.46 4 7 3 2 0 . 5 0 . 4 5 7 2 3 . 5 7 4 5 5 18.62 . 4 3 4 22.03 ' 3 3 4 15.06 . 4 0 6 2 0 . 8 6 2 0 2 1 2 . 4 1 -223-Table 4: Isotherm Data of Sommers (5) n-Pentane Dried C0_ Removed Above C r i t i c a l Poin (Cotton Dried) COp Removed Above C r i t i c a l Point P/P, 0.0140 0.0163 0.0954 0.1214 0.1678 0.1875 0.2230 0.3505 0.4.188 0.4371 0.4397 0.6012 0.6438 0.7204 0.7585 0.8377 0.9033 0.9483 0.9532 0.9&40 0.9293 0.7966 0.6233 0.5076 0.4644 0.4003 0.3149 0.1206 0.1547 0.1911 0.2134 0.2297 0.2522 0.6746 0.9370 0.9862 0.8743 0.7019 0.6450 0.5594 0.4347 0.3956 0.3106 Volume Adsorbed* 7.07 7.34 10.57 11.20 12.14 12.64 13.42 16.11 17.68 18.12 18.22 21.77 22.77 24.39 25.30 27.60 31.02 34.38 34.84 39.79 34.70 27-97 24.48 23-12 21.38 17.73 15.72 11. 05 11.77 12.51 13.03 13.36 13.82 22.94 32.94 40.28 30.88 25.27 24.44 23-36 18.76 17.25 15.34 P/P, 0.1182 0.1410 0.1619 0.1738 0.1815 0.1914 0.2412 0.2768 0.0535 0.0842 0.1529 0.2102 0.2492 0.2864 0.3900 0.4604 0.5808 0.7086 0.7733 0.9005 0.9646 0.9904 0.9449 0.8753 0.6599 0.5964 0.5557 0.4939 0.4566 0.4166 0.3640 0.3061 Volume Adsorbed* 6.49 6.68 6.83 6.91 6.97 7-03 7-37 7.65 5.64 6.06 6.72 7.12 7-37 7.62 8.72 9.36 10.65 12.28 13.10 17-99 32.25 63-34 31.11 18.83 13.17 12.68 12.46 12.02 10.82 9.28 8.53 8.00 P/P, 0.1008 0.1203 0.1479 0.1631 0.2148 0.2553 0.2923 0.1024 0.1213 0.1496 0.1650 0.2205 0.2624 0.3018 0.3556 0.4506 0.6118 0.8132 0.9106 0.9633 .0.9898 0.9673 0.9490 0.9284 0.9060 0.8470 0.7482 0.6305 0.5401 0.4727 0.4488 0.4084 0.3445 Volume Adsorbed* 9.67 9.95 10.41 10.63 11.43 11.99 12.51 9.42 9.95 10.38 10.64 11.49 12.09 12.82 13.70 15.24 17.64 21. 44 26.62 40.17 53.76 1 46.21 41.66 36.00 31.31 24.77 21. 78 20.39 19.68 18.55 16.93 15.09 13.88 Expressed as mis.(S.T.P.)/g. -224-APPENDIX C Table 5: Isotherm Data on Hollow Filament Rayon Supplied by S c a l l a n (172) Nitrogen Adsorption Smoothed Values** P/P, Volume Adsorbed* Solvent Exchange Dried P/P, Experimental Values Dried at 105°C then Solvent Exchange Dried p/p Volume Adsorbed* Volume Adsorbed* 0.185 4.6 0.20 4.77 0.18 4.58 0. 300 5.5 0.40 6.15 0.395 6.35 0.405 6.4 0.59-5 7.76 0.60 9.27 0. 430 6.6 0.815 11.38 0.80 11.61 0. 460 6.9 0.97 20.02 . 0.965 21.18 0.480 7.1 0. 500 7.3 Desorption Desorption 0.595 8.3 0.660 9.1 0.97 20.77 0.965 18.61 0. 740 10. 4 0.74 14.77 0.745 13.94 0. 790 11.5 0.50 8.97 0.50 10.03 0. 850 13.1 0.455 7.13 0.45 7.11 0. 895 14.9 0.41 6.46 0.40 6.35 0.950 18.8 0.295 5.55 0.965 20.6 0.195 4.77 Desorption 0.965 20.6 0.950 19.7 0.895 17.7 0.850 16.5 0.790 15.2 0. 740 14. 3 0. 660 12.9 0.595 11.8 0.500 9.5 0.480 8.5 0. 460 . 7.5 0.430 6.6 0.405 6.4 0.300 5.5 0.185 4.6 * Volume adsorbed expressed as mis.(S.T.P. )/g. ** These values were picked of o f f a smoothed isotherm curve and used i n a l l c a l c u l a t i o n s . -225-APPENDIX C ?able 6: A c c e s s i b i l i t y Data of Stone and S c a l l a n (69, 172) M o l e c u l a r Molecular,. D i a m e t e r , ft wt. x 10 ^ 65. I n a c c e s s i b l e Volume, ml. K r a f t P u l p , P e r c e n t Y i e l d 1 % 44.6 % 41.6 560 2000 1. 40 1.41 -270 500 1. 1.42 1. 45 140 110 1. 42 1.47 1.40 90 40 1. 45 1.25 1.20 68 20 1. 30 1.03 0.90 51 10 1. 19 0.87 0.88 45 8.8 1. 06 0.73 0.60 36 5.4 0. 92 0.54 0. 31 26 2.6 0. 69 0.38 0.33 20 1.4 0. 48 0.24 0.19 12 R a f f i n o s e 0. 31 0.14 0. 07 8 Glucose 0. 15 0.03 0. 07 - 2 2 6 -A P P E N D i X D TABLE |: PORE ANALYSIS USING STANDARDIZED NITROGEN ISOTHERMS PARALLEL SIDED FISSURE MODEL CYLINDRICAL PORE MODEL UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0 . 9 0 0 0 . 8 5 0 0 . 8 0 0 0 . 750 0 . 7 0 0 0 . 6 5 0 C . 6 0 0 _ 0 . 5 5 0 0 . 5 0 0 0 . 4 8 0 0 . 4 6 0 0 . 4 4 0 0 . 4 0 0 . 0 . 3 5 0 1 0 9 . 4 Q 0 wall separation pore Vj-rryg. turn of pore area *»rryg. pore .volume sum of A port vol A port volume m l (5T . F H A P O r e i n i ; o o o 1 6 4 . 1 0 0 1 4 9 . ? 0 0 1 3 8 . 4 0 0 1 2 8 . 7 0 0 120.BOO 9 6 . 4 B 3 6 0 . 7 8 1 5 5 . 1 2 8 4 5 . 7 2 1 3 9 . 0 9 7 3 4 . 1 3 5 ] 1 4 . 100 1 0 S . 5 0 0 9 0 . 2 0 0 flI.4 00 7 6 . 9 0 0 7 1 . 5 0 0 1 0 . 2 4 8 7 7 . 0 9 4 2 5 . 1 6 4 . 2 4 . 1 B 4 2 3 . 2 6 3 2 1 . 9 9 3 7.51 J 9 . 2 3 0 9 . 9 8 1 8 . 294 B . 4 7 7 7 . 5 5 1 6 6 . 0 0 0 2 0 . 2 4 8 6 . 9 1 6 1 0 . 3 2 7 2 2 . 2 6 9 1 2 . 6 8 6 6 . 0 5 0 6 . 54? 7 . 5 1 3 1 6 . 7 4 3 2 6 . 7 2 4 35 .Q1B 4 3 . 4 9 5 51 . 0 4 5 5 7 . 9 b 2 6 8 . 2 8 8 9 0 . 5 5 8 1 0 3 . 2 4 4 1 0 9 . 2 9 4 1 1 5 . 6 3 6 2 3 . 3 8 3 2 0 . 7 7 7 1 7 . 7 5 0 1 2 . 2 3 3 1 0 . 6 9 1 8 . 3 1 4 6 . 503 1'2'2.33B' — 6 . ? 4 8 9 . 0 2 5 1 8 . 0 7 7 9 . B97 4 . 5 4 0 4 . 6 4 1 2 3 . 3 8 3 44.159 6 1 . 9 0 9 7 4 . 1 4 2 8 4 . 8 3 3 9 3 . 1 4 7 9 9 . 8 9 5 1 0 8 . 9 2 1 1 2 6 . 9 9 7 1 3 6 . 8 9 5 1 4 1 . 4 3 5 1 4 6 . 0 7 5 6 . 6 6 3 0 0 0 I . I 4 5 6 7 9 1 . 5 8 B B 3 2 1 . 6 0 0 4 3 7 1 . 9 0 7 5 9 0 1 . 9 2 5 1 7 4 1 . 9 5 2 5 6 T 3 . 1 6 5 6 2 4 1 7 . 8 9 2 7 1 5 1 0 . 4 3 3 1 3 6 5 . 0 7 9 3 7 1 2 . 8 1 8 7 1 0 ad •. diam of .pore A turn of pore area pore ' volume mlSTfJ'g sum of pore vol A pore volume ml(S.T^.A(«« • » 4 . 2 4 7 1 5 6 . 3 2 3 3 . 3 0 4 6 9 4 " 0 . 9 0 0 19O.400 _ .. 0.850 1 B 1 . 0 0 0 8 5 . 8 3 6 9 . 2 0 6 9 . 2 0 6 2 5 . 4 9 2 2 5 . 4 9 2 0 . 7 5 8 8 2 9 0 . 8 0 0 164. 100 60.507 12.312 2 1 . 5 1 8 2 4 . 0 3 0 4 9 . 5 2 2 1 . 4 0 8 0 0 4 0.750 149.200 46.774 1 4 . 3 7 3 35^891 ' 2 1 . 6 8 7 7 1 . 2 0 9 2 . 0 8 5 2 0 8 0 . 7 0 0 138.400 38.052 1 2 . 7 0 B 4 8 . 5 9 9 1 5 . 5 9 9 8 6 . 8 0 8 2 . 2 1 4 4 2 0 0 . 6 5 0 128.700 31 . 9 7 2 1 3 . 8 6 4 62.463 1 4 . 2 9 8 1 0 1 . 1 0 6 2 . 7 9 5 1 0 8 0 . 6 0 0 120.BOO 27.462 1 2 . 9 7 B 7 5 . 4 4 1 1 1 . 4 9 7 1 1 2 . 6 6 3 2 . 9 4 3 9 7 6 0 . 5 5 0 1 1 4 . 1 0 0 23.961 12.436 8 7 . 8 7 7 9 . 6 1 2 1 2 2 . 2 1 5 3 . 1 0 3 B 9 4 0 . 5 0 0 105.500 71 . 1 4 7 20.521 1 0 8 . 3 9 8 1 3 . 9 9 8 1 3 6 . 2 1 3 5 . 5 3 0 2 9 2 0 . 480 9 0 . 7 0 0 1 9 . 4 3 5 4 9 . 1 9 0 1 5 7 . 5 8 8 3 0 . 8 4 0 1 6 7 . 0 5 3 3 4 . 6 0 8 8 2 6 0.460 81.400 18.573 27.653 1 8 5 . 2 4 1 1 6 . 5 6 8 1 8 3 . 6 2 1 1 9 . 8 7 4 3 9 0 0 . 4 4 0 76.900 1 7 . 7 6 5 12. 132 1 9 7 . 3 7 3 6 . 9 5 3 1 9 0 . 3 7 3 8 . 8 8 4 9 5 6 0 . 4 0 0 71.500 16.657 l l . 163 2 6 6 . 5 3 6 5 . 4 9 8 1 9 6 . 5 7 1 4 . 1 8 4 6 5 2 0.350 6 6 . 0 0 0 15.145 9 . 9 1 5 2 1 8 . 4 5 1 4 . 844 2 0 1 . 4 1 5 3 . 0 4 5 5 5 1 PULP BEATEN I MINUTE —SOLVENT EXCHANGE ORlEO FROM WATER SUSPENSION 0 . 9 0 0 0 . 8 5 0 o . a o o -0 . 7 5 0 0 . 7 0 0 0 . 6 5 0 0 . 6 0 0 0 . 5 5 0 0.500-0 . 4 8 0 0 . 4 6 0 0 . 4 4 0 0 . 4 0 0 0 . 3 5 0 1 8 4 . 5 0 0 1 6 0 . 3 0 0 1 4 6 . 5 0 0 1 3 5 . 0 0 0 1 2 6 . 0 0 0 1 1 9 . 0 0 0 1 1 3 . 0 0 0 1 0 7 . 0 0 0 —as.ooo 8 6 . 0 0 0 76 . 000 7 2 . 0 0 0 6 7 . 0 0 0 6 2 . 0 0 0 5 5 . 1 2 8 4 5 . 7 2 1 3 9 . 0 9 7 3 4 . 1 3 5 3 0 . 2 4 8 . 2 7 . 0 9 6 2 5 . 1 6 4 2 4 . 184 2 3 . 2 6 3 2 1 . 9 9 3 2 0 . 2 4 8 7 . 5 4 2 6 . 8 2 4 5 . 9 0 9 5 . 5 9 2 6 . 2 7 3 - J j - . 2 i . 3 _ 2 4 . S O B 3 1 . 6 3 1 3 7 . 5 4 0 4 3 . 1 3 2 4 9 . 4 0 5 5 9 . 149. . 1 8 . ' 7 8 . 0 5 7 9 2 . 7 7 6 9 8 . 142 1 0 4 . 2 7 * 1 1 0 . 2 1 8 1 3 . 4 1 3 1 0 . 0 6 4 7 . 4 5 2 6 . 1 5 8 6 . 121 B . 5 1 6 — 6 0 , 7 8 8 70 . B 32 7 8 . 3 0 4 B 4 . 4 6 2 9 0 . 5 8 3 Q Q . nw i 1 5 . 3 4 8 1 1 . 4 8 3 4 . 0 2 6 4 . 3 5 1 3 . 8 8 2 1 1 4 . 4 4 7 1 2 5 . 9 3 0 1 2 9 . 9 ^ 6 1 3 4 . 3 U 7 1 3 8 . 1 8 9 1 . 2 0 0 6 1 7 1 . 3 1 6 7 5 6 I . 3 2 9 6 3 0 1 . 4 2 5 8 5 3 1 . 7 7 1 0 0 8 7.9H4ft*5 1 5 . 1 9 1 9 4 9 1 2 . 1 0 * 9 7 9 4 . 5 0 4 6 8 8 2 . 6 4 2 3 9 0 2 . 106696 0 . 9 0 0 0 . 8 5 0 0 . 8 0 0 0 . 750 0 . 7 0 0 0 . 6 5 0 0 . 6 0 0 0 . 5 5 0 0 . 5 0 0 0 . 4 6 0 0 . 4 4 0 0 . 4 0 0 0 . 3 5 0 1 8 4 . 5 0 0 1 6 0 . 3 0 0 1 4 6 . 5 0 0 1 2 6 . 0 0 0 1 1 9 . 0 0 0 1 1 3 . 0 0 0 1 0 7 . 0 0 0 9 9 . 0 0 0 8 6 . 0 0 0 8 5 . 8 3 8 6 0 . 5 0 7 7 6 . 0 0 0 7 2 . 0 0 0 6 7 . 0 0 0 6 2 . 0 0 0 3 6 . 0 5 2 3 1 . 9 7 2 2 7 . 4 6 2 2 3 . 9 6 1 2 1 . 1 4 7 1 9 . 6 3 5 1 2 . 1 0 8 9 . B 0 2 H i . f t n s 1 8 . 5 7 3 1 7 . 7 6 5 1 6 . 6 5 7 1 5 . 145 1 0 . 4 3 5 9 . 5 4 7 9 . 5 4 7 1 1 . 4 6 7 1 9 . 6 2 2 4 1 . 7 6 2 1 2 . 1 0 8 2 1 . 9 1 0 3 7 . 7 1 5 3 2 . 6 7 3 1 0 . 6 9 3 1 0 . 6 0 7 9 . 0 5 8 4 3 . 1 5 0 5 2 . 6 9 7 6 2 . 2 4 4 7 3 . 7 1 1 9 3 . 3 3 3 .135. (195— 3 3 . 5 2 7 1 9 . 1 3 1 1 6 7 . 7 6 8 1 7 8 . 4 6 0 1 8 9 . 0 6 7 1 9 8 . 1 2 5 1 2 . 8 0 9 9 . 8 4 6 8 . 4 5 7 8 . 863 1 3 . 3 8 5 _ _ 2 6 . 1 B 3 — 3 3 . 5 2 7 5 2 . 6 5 9 1 9 . 5 7 5 6 . 1 2 8 5 . 6 9 9 4 . 4 2 5 8 1 . 7 7 1 9 1 . 6 1 7 1 0 0 . 0 7 4 1 0 8 . 9 3 7 1 2 2 . 3 2 2 0 . 9 9 8 0 2 6 1 . 1 2 0 9 6 7 I .4* .7*7* 1 6 8 . 0 8 0 1 7 4 . 2 0 8 1 7 9 . 9 0 7 1 8 4 . 3 3 2 1 . 8 1 6 4 0 2 1 . 9 2 4 8 0 2 2 . 1 6 5 S 7 0 2 . 8 6 2 0 7 7 5 . 2 8 7 9 9 6 2.9. 3 B2 401 2 3 . 4 B 2 4 0 7 7 . 8 3 0 7 7 * 3 . 9 7 6 0 2 7 2 . 7 8 2 3 9 4 PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0 . 9 0 0 o . a s c -0 . 6 0 0 0 . 7 5 0 0 . 7 0 0 0 . 6 5 0 0 . 6 0 0 . 0 . 5 5 0 -0 . 5 0 0 0 . 4 8 0 0 . 4 6 0 0 . 4 4 0 0 . 4 0 0 0 . 3 5 0 -1 4 1 . 0 0 0 1 2 7 . 5 0 0 1 1 7 . 0 0 0 1 0 8 . 5 0 0 1 0 1 . 5 0 0 — 9 5 . 5 0 0 . 9 6 . 4 8 3 6 9 . 7 8 1 5 5 . 128 4 5 . 7 2 1 3 9 . 0 9 7 3 4 . 1 3 5 - 3 0 . 2 6 8 1 1 . 8 4 1 1 0 . 2 3 8 8 . 7 8 7 7 . 8 9 5 7 . 163 6 . 4 5 7 — 5 . . a t t 8 — -1-1 . 841 2 2 . 0 7 9 3 0 . 8 6 6 3 8 . 7 6 1 4 5 . 9 2 4 5 2 . 3 B 1 S B . 3 6 9 —36.1 2 3 . 0 4 7 1 5 . 6 2 6 1 1 . 6 4 3 9 . 0 3 4 7 . 110 5 - ^ a 4 3 _ _ 3 6 . . a a 3 -89 . 5 0 0 ' 8 4 . 0 0 0 7 2 . 5 0 0 6 8 . 5 0 0 6 3 . 0 0 0 - 5 9 . 0 0 0 2 7 . 0 9 4 2 5 . 164 2 4 . 1 8 4 2 3 . 2 6 3 2 1 . 9 9 3 _ 2 0 . 2 4 8 6 . 6 5 9 7 . 5 1 3 1 7 . 1 3 7 5 . 4 0 3 7 . 0 6 3 4 . 1 6 S -6 5 . 0 2 8 7 2 . 5 4 1 8 9 . 6 7 8 9 5 . 0 8 1 1 0 2 . 1 4 5 -III 5 . 8 2 0 6 . 0 9 8 "13 .369 4 . 0 5 5 5 . 0 1 1 3. 7?l> 5 9 . 9 0 0 7 5 . 5 2 6 8 7 . 1 6 9 9 6 . 2 0 3 1 0 3 . 3 1 4 . 1 0 9 . 1 5 f t .11**9**. 1 1 4 . 9 7 7 1 2 1 . 0 7 5 1 3 4 . 4 4 4 1 3 8 . 4 9 9 1 * 3 . 5 1 0 | ** , T J3 l1 1 . 2 7 0 8 6 * 1 . 3 9 8 7 1 4 1 . 5 2 3 3 7 0 1 . 6 1 1 9 5 6 1 . 6 * 6 3 5 6 1 ,f.Ollt.*q 2 . 0 4 1 3 8 6 6 . 0 3 6 0 6 * 1 4 . 0 9 3 4 2 0 4 . 5 3 6 5 0 9 3 . 0 4 3 3 9 6 1 T *7rSlf t9 0 . 9 0 0 0 . 8 5 0 0 . 8 0 0 0 . 7 5 0 r . , 7nn 0 . 6 5 0 0 . 6 0 0 0 . 5 5 0 0 . 5 0 0 0 . 4 8 0 O . 4 6 0 0 . 4 4 0 0 . 4 0 0 0 . 3 5 0 1 8 9 . 0 0 0 1 6 0 . 0 0 0 1 4 1 . 0 0 0 1 2 7 . 5 0 0 I 17.OOP 1 0 8 . 5 0 0 1 0 1 . 5 0 0 9 5 . 5 0 0 8 9 . 5 0 0 8 4 . 0 0 0 7 ? r * o n 8 5 . 8 3 8 6 0 . 5 0 7 4 6 . 7 7 4 3 B . O S 7 6 8 . 5 0 0 6 3 . 0 0 0 5 9 . 0 0 0 : 3 1 . 9 7 2 2 7 . 4 6 2 2 3 . 9 6 1 2 1 . 147 1 9 . 4 3 5 1 4 . 5 1 0 1 3 . 6 1 3 1 2 . 5 5 3 1 7 . 7 6 5 1 6 . 6 5 7 1 5 . 1 4 5 1 1 . 5 7 5 1 0 . 9 7 2 1 0 . 6 5 8 1 2 . 6 8 6 1 6 . 0 4 3 3H .73Q 1 4 . 5 1 0 2 8 . 1 2 3 4 0 . 6 7 7 5 ? - 7 1 3 1 1 . 1 1 6 1 3 . 6 7 1 4 . 8 9 8 6 4 . 2 B B 7 5 . 2 6 0 8 5 . 9 1 8 9 8 . 6 0 4 1 1 4 . 6 * 7 _ 1 3 3 . 3 7 7 _ 4 0 . 1 7 8 2 6 . 5 7 2 1 8 . 9 4 1 1 4 - 7 7 4 1 6 4 . 4 9 3 1 7 8 . 1 6 4 1 8 3 . 0 6 2 1 1 . 9 3 8 9 . 7 2 0 8 . 2 3 8 8 . 6 5 4 1 0 . 0 5 8 3 3 T 7 Q * 4 0 . 1 7 8 6 6 . 7 4 9 85.6*90 1 0 0 - 4 6 4 6 . 3 7 0 7 . 3 4 6 2 . 3 9 3 1 1 2 . 4 0 2 1 2 2 . 1 2 1 1 3 0 . 3 5 9 1 3 9 . 0 1 3 1 4 9 . 0 7 1 - 1 7 2 . 2 75. 1 . 1 9 5 9 8 0 1 . 5 5 6 9 0 0 1 . 6 2 1 1 6 2 2 . 0 9 7 3 * 9 1 7 8 . 6 4 6 1 8 5 . 9 9 1 1 8 8 . 3 8 4 2 . 3 3 3 6 4 8 2 . 4 6 6 9 2 5 2 . 6 6 0 1 2 7 3 . 4 1 B 7 6 0 11 . 2 8 7 4 6 9 140728 5 . 1 2 4 6 8 1 1 . 5 0 4 4 B 6 PULP BEATEN 5 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0 . 9 0 0 _ 0 . 8 5 0 0 . 8 0 0 0 . 7 5 0 0 . 7 0 0 0 . 6 5 0 1 -13.01-111 0 . 5 5 0 0 . 5 0 0 0 . 4 8 0 0 . 4 6 0 0 . 4 4 0 0 . 4 0 0 — 0 . 3 5 0 1 3 0 . 0 0 0 1 1 6 . 0 0 0 1 0 6 . 0 0 0 9 9 . 0 0 0 9 3 . 0 0 0 u n . * n n 9 6 . 4 8 3 6 9 . 7 8 1 5 5 . 1 2 8 4 5 . 7 2 1 3 9 . 0 9 7 3 4 . 1 3 * 8 4 . 5 0 0 8 1 . 0 0 0 7 8 . 0 0 0 6 7 . 0 0 0 6 3 . 0 0 0 ST. .5110-3 0 . 2 4 8 2 7 . 0 9 4 2 5 . 164 2 4 . 1 8 4 2 3 . 2 6 3 - 2 - U 5 . 166 5 . 0 1 7 * - " 7 3 3 . 9 1 0 3 . 6 5 8 3 . 9 8 0 1 6 . 6 3 9 5 . 6 9 6 7 ->>** 9 . 3 9 1 1 6 , 9 0 8 2 3 . 3 9 6 2 8 . 5 6 2 3 3 . 5 7 9 4 1 . 5 1 1 4 5 . 1 6 9 4 9 . 1 4 B 6 5 . 7 8 7 7 1 . 4 8 3 79- n i l 2 9 . 2 2 8 1 6 . 9 2 1 1 1 . 5 3 8 7 . 6 1 8 6 . 3 2 7 * - * 3 i j 2 9 . 2 2 8 * 6 . l * 9 5 7 . 6 0 7 6 5 . 3 0 6 71 . 6 3 3 5 3 . 5 0 0 2 0 . 2 4 8 4 . 8 9 0 8 4 . 0 1 8 3 . 8 1 5 3 . 197 3 . 2 30 1 2 . 9 8 1 4 . 2 7 4 3 . 194 7 9 . 8 7 7 8 3 . 0 7 * 8 6 . 3 0 5 9 9 . 2 B 5 1 0 3 . 5 5 9 , H l H .9r t3 0 . 8 2 8 7 5 0 0 . 9 3 3 0 5 6 1 . 0 3 2 8 1 7 0 . 9 9 6 7 6 1 1 . 1 2 8 9 7 8 1 . 1 0 3 7 1 0 1 . 1 2 1 2 2 6 3 . 1 9 7 5 3 2 1 3 . 6 8 3 5 8 0 4 . 7 8 1 9 0 * 3 . 7 9 * 0 9(1 0 , 9 0 0 0 . B 5 0 0 . 8 0 0 0 . 7 5 0 0 . 7 0 0 0 . 6 0 0 0 . 5 5 0 0 . 5 0 0 0 . 4 80 0 . 4 6 0 .Q...440— 1 5 3 . 0 0 0 1 3 0 . 0 0 0 1 1 6 . 0 0 0 1 0 6 . 0 0 0 9 9 . 0 0 0 9 3 . 0 0 0 8 5 . 8 3 8 6 0 . 5 0 7 4 6 . 7 7 * 3 8 . 0 5 2 —31 .9 .72 . 1 1 . 5 0 8 9 . 9 8 6 9 . 2 6 3 7 . 8 2 4 • 093 8 8 . 5 0 0 8 4 . 5 0 0 8 1 . 0 0 0 7 8 . 0 0 0 6 7 . 0 0 0 6 3 . 0 0 0 — 2 7 . 4 6 2 2 3 . 9 6 1 2 1 . 147 1 9 . 4 3 5 1 8 . 5 7 3 - 1 7 . 7 6 5 6 . 7 3 8 6 . 9 0 4 6 . 7 2 * B . 3 B 6 3 8 . 0 1 9 12.281 1 1 . 5 0 8 2 1 . 4 9 4 3 0 . 7 5 7 3 8 . 5 8 0 _ 4 6 . 6 . 7 - 3 _ 3 1 . 8 6 5 1.9.492 1 3 . 9 7 6 9 . 6 0 3 8 - 3* t\ 31 . 8 6 5 5 1 . 3 5 7 6 5 . 3 3 2 7 4 . 9 3 6 H3.7H7 5 3 . 4 1 1 6 0 . 3 1 5 6 7 . 0 3 9 7 5 . 4 2 6 1 1 3 . 4 4 5 125..-73S 5 . 9 6 9 5 . 3 3 6 4 . 5 8 7 5 . 2 5 B 2 2 . 7 7 8 7 . 0 6 3 . 8 9 . 2 5 1 9 4 . 5 8 7 99 .1 74 1 0 4 . 4 3 2 1 2 7 . 2 1 0 - 1 3 4 . 2 5 6 0 . 9 4 8 5 3 7 1 . 1 4 2 0 7 6 1 . 3 4 3 7 8 2 1 . 3 6 3 2 9 5 1.6316. I A 1 . 5 2 8 4 8 9 1 . 7 2 3 1 7 7 1 . 8 1 2 1 3 2 5 . 9 0 0 3 8 3 2 7 . 3 2 4 5 2 4 9 . 0 0 0 B O 6, 1 1 2 . 1 7 7 1 . 7 3 3 2 9 9 PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0 . 9 0 0 0 . 8 5 0 0 . 8 0 0 0 . 7 5 0 0 . 7 0 0 £U.63Q„ 0 . 6 0 0 0 . 5 5 0 . 0 . 5 0 0 0 . 4 8 0 0 . 4 6 0 1 5 9 . 0 0 0 1 3 6 . 0 0 0 1 2 2 . 0 0 0 1 1 1 . 0 0 0 1 0 2 . 0 0 0 9*,»nrt 9 0 . 0 0 0 8 5 . 5 0 0 8 0 . 5 0 0 7 6 . 0 0 0 66 . 000 >-3 . nnfi 9 6 . 4 8 3 6 9 . 7 8 1 5 5 . 1 2 8 4 5 . 7 2 1 *q -flQ7 3 4 . 135 3 0 . 2 4 8 2 7 . 0 9 4 2 5 . 1 6 4 2 4 . 184 _ 2 3 . 2 6 3 . . 3 9 1 . 5 1 7 . 2 0 0 5 . 6 4 4 * . 4 2 2 5 . 6 3 1 9 . 3 9 1 1 6 . 9 0 8 2 * . 1 0 8 3 0 . 9 5 6 3*. .HQ* 4 1 . 5 3 8 4 5 . 9 6 0 5 1 . 591 5 7 . 7 5 7 7 2 . 7 2 4 7 * - 7 i n 2 9 . 2 2 8 1 6 . 9 2 1 1 2 . 8 0 4 1 0 . 1 0 0 6 . 2 1 5 4 . 3 1 * 4 . 9 2 1 5.005 1 1 . 6 7 6 2 , 9 9 1 2 9 . 2 2 8 4 6 . 1 4 9 5 B . 9 5 3 6 9 . 0 5 3 75 .7H1 81 . 4 9 6 8 5 . 8 1 0 9 0 . 7 3 2 9 5 . 7 3 7 1 0 7 . 4 1 3 -L lO^AU-4 -0 . B 2 8 7 5 O 0 . 9 3 3 0 5 6 1 . 146091 1 . 3 2 1 4 2 6 • 1 . 1 1 1 ? 9 5 1 . 4 3 9 1 1 2 I . 2 4 8 3 1 4 1 .726151 4 . 9 5 4 3 8 4 1 2 . 3 0 8 5 0 4 3 .3** ,?41 0 . 9 0 0 1 5 9 . 0 0 0 0 . 8 5 0 0 . 8 0 0 0 . 7 5 0 0 . 7 0 0 0 . 6 5 0 0 . 5 5 0 0 . 5 0 0 0 . 4 8 0 0 . 4 6 0 0 . 4 * 0 1 3 6 . 0 0 0 1 2 2 . 0 0 0 1 1 1 . 0 0 0 1 0 2 . 0 0 0 9 6 . 0 0 0 m T n n n 8 5 . 5 0 0 8 0 . 5 0 0 7 6 . 0 0 0 6 6 . 0 0 0 ' 6 3 . 0 0 0 - 5 9 . 0 0 0 -8 5 . 8 3 8 6 0 . 5 0 7 4 6 . 7 7 4 3 8 . 0 5 2 3 1 . 9 7 2 37 T * A 7 2 3 . 9 6 1 2 1 . 1 4 7 1 9 . 4 3 5 I B . 573 1 7 . 7 6 5 0 . 3 5 0 5 5 . 0 0 0 1 5 . 1 4 5 1 1 . 5 0 8 9 . 9 8 6 1 0 . 3 0 6 1 0 . 4 B 6 ? . B B 3 — 9 - * . q * 7 . 7 8 1 1 0 . 8 3 4 1 3 . 1 8 7 3 3 . 9 0 6 6 . 0 2 7 1 1 . 5 0 8 2 1 . 4 9 4 3 1 . 8 0 0 4 2 . 2 8 6 5 0 . 1 6 9 5 9 . A / . * 6 7 . 6 * 5 7 8 . 4 7 9 9 1 . 6 6 3 1 2 5 . 5 7 2 1 3 3 . 5 9 9 i * 3 - W 7 . 9 9 6 1 5 0 . 6 5 8 3 1 . 8 6 5 1 9 . 4 9 2 1 5 . 5 5 0 1 2 . 8 7 1 8 . 130 6 . 0 1 * 7 . 3 9 0 8 . 2 6 7 2 0 . 3 1 4 4 . 6 0 0 . 6 7 0 -3 1 . 8 6 5 5 1 . 3 5 7 6 6 . 9 0 7 7 9 . 7 7 7 8 7 . 9 0 7 9f t ,497 1 0 2 . 5 1 0 1 0 9 . 9 0 1 1 1 8 . 1 6 8 1 3 B . 4 8 2 1 4 3 . 0 8 2 1*7 - 9 * ? 0 . 9 4 6 5 3 7 1 . 1 4 2 0 7 6 1 . 4 9 5 1 3 2 . 1 . 8 2 7 1 8 9 1 .5B92B7 j . i 00*09! 1 .942039 ' 2 . 9 1 9 5 7 8 9 . 2 77696 24 .3689731 5 . B 7 B 5 4 6 1 3 . 3 Q 7 7 9 7 3 . 9 0 7 1 5 1 . 8 5 9 2 . 4 5 6 2 5 4 -227-TABLE I. CONTINUED PARALLEL SIDED FISSURE MODEL CYLINDRICAL PORE MODEL 'UNBEATEN PULP S H E E T S — V A C U U M DRIED PRIOR TO SOLVENT EXCHANGE DRYING a. ago . ;»• * o-mo •0.b50 3.0bo o.boo 2.980-J 1 . 2 U U . S O J L 10.700 2.850 10.630 2 . b i s g;Sgg *-7'° 0.900 10*480-. 0.440 0.440 0.400 • o T T S o -S.YJ6 . 2 . 6 2 0 ,.i*.46j>_ 2 . 2 1 0 2 . 0 6 0 1 . 9 8 0 1 . 7 5 9 ' Mparatton, A 9 6 . 4 8 9 6 9 . 7 8 1 _ 5 5 . J 2 8 4 5 . 7 2 i 3 9 . 0 9 T 3 4 . 1 3 5 30 .248 2 7 . 0 9 4 _ 2 A . . 1 M . 2 4 . 1 8 4 2 3 . 2 6 3 2 1 . 9 9 3 0 . 6 * 7 0 . 0 5 4 _0^_053 0 . 0 3 7 0 . 0 2 8 0 . 0 3 2 0.055 0 . 1 4 9 . . 0 . 2 3 6 0 . 3 B 3 0 . 2 3 1 0 . 1 0 4 2 0 . 2 4 8 87571 0 . 0 5 7 Q . U l 0 . 1 6 4 0 . 2 0 1 0 . 2 2 9 0 . 2 6 1 0.517 0 . 4 6 2 0 . 6 9 8 1 . 0 8 1 1 . 3 1 2 1 . 4 1 6 1.787 v d u r m ' . mLSTfyg 0 . 1 7 8 0 . 1 2 2 0 . 0 9 4 0 . 0 5 5 0 . 0 3 5 0 . 0 3 6 0 . 0 5 4 0 . 1 2 7 0 . 1 9 2 0 . 2 9 9 0 . 1 7 3 0 . 0 7 4 0 . 2 4 2 sum of pore v o l Aj*>" 0 . 1 7 8 0 . 3 0 0 0 . 3 9 4 0 . 4 4 8 0 . 4 8 4 0 . 5 1 9 0.573 0 . 7 0 0 0 . 8 9 1 1 . 1 9 0 1 . 3 6 3 1 . 4 3 8 £POTt U2t " 0 . 0 0 5 0 4 5 0 . 0 0 6 7 1 5 1 . 0 . 0 0 8 4 0 4 0 . 0 0 7 1 4 0 0 . 0 0 6 3 3 1 0 . 0 0 8 2 3 5 0 . 0 1 5 6 1 1 0 . 0 4 4 4 4 9 0 . 1 8 9 5 8 3 0 . 3 1 5 1 9 4 0 . 1 9 3 5 5 7 0 . 0 4 5 0 2 7 1 . 6 8 0 0 . 1 3 1 4 0 2 G . 9 0 0 0 . 8 5 0 0 . 8 0 0 0 . 750 0 . 7 0 0 0 . 6 5 0 0 . 6 0 0 0 . 5 5 0 0 . 5 0 0 0 . 4 S C 0 . 4 6 0 0 . 4 4 0 0 . 4 0 0 0 . 3 5 0 3 . 2 2 0 3 . 0 8 0 2 . 9 8 0 2 . 9 0 0 2 . 6 5 0 2 . 8 1 5 2 . 7 8 0 2 . 7 5 0 2 . 6 2 0 2 . 4 6 0 2 . 2 1 0 2 . 0 6 0 1 .980 diarn. of port A 8 5 . 8 3 8 6 0 . 5 0 7 4 6 . 7 7 4 3 8 . 0 5 2 3 1 . 9 7 2 2 7 . 4 6 2 2 3 . 9 6 1 2 1 . 1 4 7 1 9 . 4 3 5 1 6 . 5 7 3 1 7 . 7 6 5 1 6 . 6 5 7 1 . 7 5 5 1 5 . 1 4 5 0 . 0 7 0 0 . 0 7 2 0 . 0 7 6 0 . 0 5 6 0 . 0 4 4 0 . 0 5 5 0 . 1 0 5 0 . 3 0 5 0 . 5 2 4 0 . 8 7 6 0 . 5 2 2 0 . 1 7 9 0 . 8 9 8 turn of : par* a m ; 0 . 0 7 0 0 . 1 4 2 0 . 2 1 R 0 . 2 7 4 0 . 3 1 8 OTTTI 0 . 4 7 8 0 . 7 8 3 1 . 3 0 7 2 . 1 8 3 2 . T 0 5 2 . 8 8 4 3 . 7 8 2 voJumt 0 . 1 9 4 0 . 141 0 . 114 0 . 0 6 9 0 . 0 4 6 0 . 0 4 9 0 . 0 8 1 0 . 2 0 8 0 . 3 2 9 0 . 5 2 5 0 . 2 9 9 sum of pore vol A P O " volumt .'im&TJH-*p"tM**! 0 . 1 9 4 0 . 3 3 4 0 . 4 4 9 0 . 5 1 7 0 . 5 6 3 0 . 6 1 2 0 . 6 9 3 0 . 9 0 1 1 . 2 3 0 1 . 7 5 4 2 . 0 5 3 2 . 1 5 0 2 . 5 8 9 0 . 0 0 5 7 7 4 0 . 0 0 8 2 3 4 0 . 0 1 0 9 8 6 0 . 0 0 9 7 5 6 0 . 0 0 8 9 6 1 0 . 0 1 2 4 A 8 0 . 0 2 6 1 0 7 0 . 0 8 2 2 7 8 0 . 3 6 8 7 0 2 0 . 6 2 9 3 2 1 . 0 . 3 B 2 1 4 2 UNBEATEN PULP SHEETS WITH 8 : 3 % MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING 0.900 ; 0 . 8 5 0 0 . 8 0 0 !ftt .7W„ 0 . 7 0 0 0 . 6 5 0 0 . 6 0 0 6.550 0 . 9 0 0 ,0*486— 0.460 0.440 0.400 0.353 4 . 4 7 2 * - « A . . 4 . 3 4 1 4 . 2 7 9 4 . 2 0 5 4.12V 3 . 8 5 0 . - 3 . 5 3 0 9 6 . 4 8 3 6 9 . 7 8 1 ,A?i.l2_8_„ 4 5 . 7 2 1 3 9 . 0 9 7 3 4 . 1 3 5 • 36 .244 6.665 0 . 0 5 3 0 . 0 4 9 0 . 0 5 5 0 . 0 7 5 O.OAfl 3 . 2 3 0 2 . 9 3 0 2 . 6 6 9 2 4 . 1 8 4 2 3 . 2 6 3 2 1 . 9 9 3 26.248 0.459 0.466 0 .399 6.247 6 . 6 6 5 0 . 1 1 8 0 . 1 6 1 0 . 2 1 0 0 . 2 6 5 0 . 3 4 0 0.424 " 0 . 8 0 9 1.278. 1 . 7 3 3 ' 2 . 199 2 . 9 9 8 2.895 0 . 2 6 3 0 . 1 1 8 0 . 0 7 7 0 . 072 0 . 0 6 9 0 . 0 8 3 0 . 0 8 6 0 . 3 2 9 0 . 3 8 4 0 . 3 5 5 0 . 3 5 0 0 . 2 8 3 0 . 1 4 4 6.263 0 . 3 2 2 _ 0 . 3 9 9 0 . 4 7 1 0 . 5 4 0 0 . 6 2 3 . 0 . 7 0 4 1 . 0 3 8 1 . 4 2 2 " 1 . 7 7 7 2 . 1 2 7 2 . 4 1 0 2 . 6 0 4 6 . 6 6 5 7 6 5 , 0 . 0 0 6 5 3 3 0 . 0 0 6 8 9 2 0 . 0 0 9 4 6 5 0 . 0 1 2 2 9 3 0 . 0 1 9 1 B 1 0 . 0 2 4 4 4 2 0 . 1 1 5 3 7 5 0 . 3 8 0 3 2 4 0 . 3 7 3 6 1 2 0 . 3 9 1 5 2 5 0 . 171941 6 . 1 0 5 1 1 0 0 . 9 0 0 0 . B 5 0 0 . 8 0 0 0 . 7 5 0 0 . 7 0 0 0 . 6 5 0 0 . 6 0 0 0 . 5 5 0 0 . 5 0 0 0 . 4 8 0 0 . 4 6 0 0 . 4 4 0 . , 4 . 7 3 0 4 . 5 7 0 4 . 4 7 2 4 , 4 0 5 4 . 3 4 1 4 . 2 7 9 8 5 . 8 3 8 6 0 . 5 0 7 4 6 . 7 7 4 3 8 . 0 5 2 3 1 . 9 7 2 4 . 2 0 5 4 . 127 3 . A 5 0 3 . 5 3 0 3 . 2 3 0 2 . 9 3 0 , 2 7 . 4 6 2 2 3 . 9 6 1 2 1 . 1 4 7 1 9 . 4 3 5 1 8 . 5 7 3 1 7 . 7 6 5 1 6 . 6 5 7 1 5 . 1 4 5 0 . 0 8 0 0 . 0 7 0 0 . 0 6 2 0 . 0 7 5 0 . 0 9 0 0 . 1 3 4 0 . 1 6 8 0 . 8 0 4 1 . 0 5 0 1 . 0 2 3 1 .067 0 . 0 8 0 0 . 1 5 0 0 . 2 1 2 0 . 2 8 7 0 . 3 7 7 0 . 8 6 7 C . 5 6 9 6.511 0 . 6 7 S 1 . 4 8 2 2 . 5 3 2 3 . 5 5 6 4 . 6 2 3 -0 . 2 2 2 0 . 1 3 6 0 . 0 9 3 0 . 0 4 3 0 . 0 9 3 6 . 114 0 . 1 3 0 0 . 5 4 8 0 . 6 5 9 0 . 6 1 3 0 . 6 1 2 0 . 7 5 5 0 . 8 8 5 1 . 4 3 3 2 . 0 9 1 2 . 7 0 5 3 . 3 1 6 0 . 0 0 6 5 9 9 0 . 0 0 7 9 9 8 O.0OB956 0 . 0 1 3 1 3 2 0 . 0 1 8 1 3 9 6 . 6 3 6 3 6 1 0 . 0 4 1 8 3 5 0 . 2 1 6 5 6 9 0 . 7 3 9 0 3 0 0 . 7 3 5 5 1 0 0 . 7 8 1 7 3 0 j UNBEATEN PULP SHEETS WITH 14.4% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING 0.900 . 0 . 8 5 0 0 . 8 0 0 • J > . 7 9 Q _ 0 . 7 0 0 0 . 6 5 0 0 . 6 0 0 6.556 0 . 5 0 0 .f l .4B.0„ 0 . 4 6 0 0 . 4 4 0 1 3 . 6 3 0 - J 3 . 5.0.0. 1 3 . 3 5 0 1 3 . 2 0 0 1 3 . 0 5 0 U . f l f t t i 1 2 . 1 8 0 _ l l » M f l 9 . 7 0 0 9 . 1 2 0 8 . 3 4 0 — 7 . 6 2 6 96 . 463 69 .781 _ 5 ? . . 1 2 8 _ . . . 4 5 . 7 2 1 3 9 . 0 9 7 3 4 . 1 3 3 36.248 2 7 . 0 9 4 2 5 . 1 6 4  2 4 . 1 8 4 2 3 . 2 6 3 2 1 . 9 9 3 26.246 6.646 0 . 0 7 5 0 . 0 8 6 6 . 1 1 9 0 . 1 3 7 0 . 1 5 3 6.145 0 . 9 9 8 _ i«231 2 . 5 4 9 0 . 6 7 4 1 . 1 7 5 _ T _ .086 6.040 0 . 1 6 5 0 . 2 9 2 _ 0 . 3 7 1 0 . 5 0 8 0 . 6 6 1 0.856 1 . 6 1 4 3 . 0 4 9 . 5 . 5 9 4 6 . 4 6 6 7 . 6 4 2 6.731 0 . 2 6 0 0 . 1 7 0 0 . 1 5 4 0 . 1 7 6 ' 0 . 1 7 2 0 . 1 6 9 0 . 1 4 0 0 . 8 3 7 0 . 9 9 9 1 . 9 8 8 0 . 6 5 6 0 . 8 3 3 0 . 7 1 1 0 . 2 6 0 0 . 4 4 9 0 . 6 0 3 0 . 7 7 9 0 . 9 9 t 1 . 1 2 0 1 . 3 1 0 2 . 1 4 8 3 . 1 4 7 5 . 1 3 5 5 . 7 9 1 6 . 6 2 5 7 . 3 3 5 0 . 0 0 7 9 2 7 0 . 0 0 9 3 5 1 0 . 0 1 3 7 4 9 0 . 0 2 3 0 2 7 0 . 0 3 0 7 5 9 0 . 0 3 9 1 1 8 0 . 0 5 5 0 6 0 0 . 2 9 3 6 7 6 0 . 9 8 9 1 4 3 2 . 0 9 5 9 2 1 0 . 7 3 3 9 0 2 0 . 5 0 6 1 4 7 0 . 3 S 5 7 3 0 0 . 9 0 0 0 . 6 5 0 0 . 8 0 0 0 . 7 5 0 0 . 7 0 0 0 . 6 9 0 0 . 6 0 0 0 . 5 5 0 0 . 5 0 0 0 . 4 8 0 0 . 4 6 0 0 . 4 4 0 1 3 . 9 9 0 1 3 . 7 7 0 1 3 . 6 3 0 1 3 . 5 0 0 1 3 . 3 5 0 1 3 . 2 0 0 1 3 . 0 5 0 1 2 . 8 8 0 1 2 . 1 8 0 1 1 . 3 5 0 ' 9 . 7 0 0 9 . 1 2 0 8 5 . 8 3 8 6 0 . 5 0 7 4 6 . 7 7 4 3 8 . 0 5 2 3 1 . 9 7 2 B.34'6™ 7 . 6 2 0 2 7 . 4 6 2 2 3 . 9 6 1 2 1 . 1 4 7 1 9 . 4 3 5 1 8 . 5 7 3 1 7 . 7 6 5 • U.65Y 0 . 110 0 . 1 0 0 0 . 124 0 . 186 Q . 2 2 8 0 . 1 1 0 0 . 2 1 0 0 . 3 3 4 . 9 2 0 . 7 4 7 0 . 2 7 2 0 . 3 7 1 ' 2 . 0 5 2 2 . 7 3 6 5 . 8 4 9 1 .412 1 . 0 2 0 1 .391 3 . 4 4 3 6 . 179 1 2 . 0 2 7 1 3 . 9 3 9 1 6 . 4 7 6 1 8 . 7 1 3 0 . 3 0 5 0 . 1 9 5 0 . 1 8 7 0 . 2 2 8 0 . 2 3 5 6 . 2 4 1 0 . 2 8 7 1 . 4 0 0 1 . 7 1 5 3 . 5 0 4 1 . 0 9 6 1 . 3 5 4 0 . 3 0 5 0 . 5 0 0 0 .68D 0 . 9 1 5 1 . 1 5 0 1 .391 1 . 6 7 8 3 . 0 7 8 4 . 7 9 3 8 . 2 9 7 9 . 3 9 3 16.752 0 . 0 0 9 0 7 3 0 . 0 1 1 4 5 2 0 . 0 1 8 0 1 6 0 . 0 3 2 3 3 2 0 . 0 4 3 8 6 9 . 6.641767 0 . 0 9 2 6 3 3 0 . 9 5 3 0 6 7 1 . 9 2 4 6 1 9 4 . 2 0 3 5 1 1 1 . 4 0 0 3 6 2 6 . 4 4 S 4 2 0 1 . 0 4 6 1 1 . 8 4 8 0 . 6 8 9 0 2 2 , UNBEATEN PULP S H E E T S WITH 3 3 j S % MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING P. 0 . 8 5 0 0 . 600 0 . 7 5 0 0 . 7 0 0 0 . 6 5 0 0 . 6 0 0 1 2 0 . 8 0 0 6.536 0 . 5 0 0 0 . 4 8 0 1 1 5 . 7 0 0 1 0 9 . 8 0 0 1 0 1 * 4 0 Q _ . 9 6 . 9 0 0 9 1 . 1 0 0 8 3 . 8 0 0 61.660 . 0 . 4 6 0 , 0 . 4 4 0 ' 0 . 4 0 0 9 6 . 4 8 3 6 9 . 7 8 1 . . -2A- .MA-4 5 . 7 2 1 3 9 . 0 9 7 3 4 . 1 3 3 30.246 5 6 . 8 0 0 5 0 . 9 0 0 4 6 . 3 0 0 6.556_ 42.766 2 4 . 1 8 4 2 3 . 2 6 3 2 1 . 9 9 3 2 . 6 A * 3 . 2 4 4 4 ^ 3 5 6 5 . 2 1 3 5 . 2 6 7 5 . 3 9 0 5 . 2 4 6 9 . 4 6 6 1.5.816 8 . 7 1 9 8 . 7 9 5 5 . 7 1 1 4 . 3 1 5 2.6a* 5 . 3 2 7 , 9 . 6 8 3 1 4 . 8 9 6 2 0 . 1 6 3 2 5 . 9 1 4 5 0 . 8 0 9 4 0 . 2 7 5 5 6 . 0 9 1 6 4 . 8 1 0 7 3 . 6 0 3 7 9 . 3 1 6 B 3 . 6 3 1 6 . 4 8 1 7 . 3 0 3 7 . 7 4 7 7 . 6 8 9 6 . 6 4 3 5 . 8 9 2 5 . 1 4 7 8 . 2 7 3 1 2 . 8 3 8 6 . 8 0 2 6 . 6 0 0 4 . 0 5 2 2 . 9 4 9 " 6 . 4 6 1 1 3 . 7 8 4 2 1 . 5 3 1 " 2 9 . 2 2 0 3 5 . 8 6 3 4 1 . 7 5 4 4 6 . 4 2 1 5 9 . 1 9 4 6 8 . 0 3 3 7 4 . 8 3 5 . 0 1 . 4 3 3 8 5 . 4 B 6 8 8 . 4 3 6 6 . 1 6 3 7 6 6 0 . 4 0 2 7 0 6 0 . 6 9 3 4 7 2 1 . 0 0 5 9 5 8 1 . 1 8 5 2 5 1 1 . 3 6 4 2 1 6 1 . 4 4 5 6 2 9 2 . 9 0 1 6 7 9 1 2 . 7 0 7 7 1 0 ' 7 . 1 7 0 1 7 4 7 . 3 8 4 3 1 3 2 . 4 6 0 8 4 6 " " 1 . 6 0 0 3 3 2 . 0 . 9 0 0 120.8~00 0 . 8 5 0 1 1 5 . 7 0 0 8 5 . 8 3 8 2 . 5 5 2 2 . 5 5 2 7 . 0 6 6 . 7 . 0 6 6 0 . 2 1 0 3 2 7 0 . 8 0 0 109.BOO 6 0 . 5 0 7 4 . 3 3 4 6 . 8 8 6 8 . 4 6 0 1 9 . 5 2 6 0 . 4 9 5 7 0 2 0 . 7 5 0 1 0 3 . 4 0 0 4 6 . 7 7 4 6 . 3 0 2 1 3 . 1 8 8 9 . 5 0 9 2 5 . 0 3 4 0 . 9 1 4 2 6 6 0 . 7 0 0 9 6 . 9 0 0 . 3 8 . 0 5 2 8 . 1 1 2 2 1 . 3 0 0 9 . 9 5 7 3 4 . 9 9 2 1 . 4 1 3 5 5 6 0 . 6 5 0 9 1 . 1 0 0 3 1 . 9 7 2 8 . 7 2 9 3 0 . 0 2 9 9 . 0 0 3 4 3 . 9 9 5 1 . 7 5 9 9 3 8 0 . 6 0 0 65.BOO 2 7 . 4 6 2 9 . 4 0 8 3 9 . 4 3 7 8 . 3 3 4 5 2 . 3 2 8 2 . 1 3 3 4 4 6 0 . 5 5 0 8 1 . 0 0 0 2 3 . 9 6 1 9 . 8 1 7 4 9 . 2 5 4 7 . 5 8 8 5 9 . 9 1 6 2 . 4 5 0 3 6 5 0 . 5 0 0 7 3 . 6 0 0 2 1 . 1 4 7 1 9 , 4 0 5 6 8 . 6 5 9 1 3 . 2 3 7 7 3 . 1 5 3 5 . 2 2 9 5 2 4 0 . 4 8 0 62.BOO 1 9 . 4 3 5 3 4 . 9 3 9 1 0 3 . 5 9 6 2 1 . 4 0 5 9 5 . 0 5 8 2 4 . 5 8 1 7 2 6 0 . 4 6 0 5 6 . 8 0 0 1 8 . 5 7 3 1 8 . 9 6 3 1 2 2 . 5 6 1 1 1 . 3 6 2 1 0 6 . 4 2 0 1 3 . 6 2 9 2 9 2 0 . 4 4 0 5 0 . 9 0 0 1 7 . 7 6 5 1 9 . 4 4 5 1 4 2 . 0 0 7 1 1 . 1 4 3 1 1 7 . 5 6 3 1 4 . 2 4 0 4 3 3 0 . 4 0 0 4 6 . 5 0 0 1 6 . 6 5 7 1 0 . 2 6 1 1 5 2 . 2 d 8 5 . 5 2 4 1 2 3 . 6 8 7 3 . 0 5 3 4 2 2 0 . 3 5 0 4 2 . 7 0 0 1 5 . 1 4 5 6 . 1 3 4 1 5 8 . 4 2 1 2 . 9 9 7 1 2 6 . 0 8 4 1 . 8 8 4 1 6 0 -228-;TABLE 2= PORE ANALYSIS USING EXPERIMENTAL VALUES OF NITROGEN ISOTHERMS; PARALLEL SIDED FISSURE MODEL PARALLEL SIDED FISSURE MODEL UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE ORYING, 0 . 9 6 0 2 3 1 . 3 4 0 separation... A 0 . 9 2 8 0 . B 8 2 0 . 8 1 4 0 . 7 6 0 0 . 6 B B 0 . 6 0 9 0 . 5 5 8 0 . 5 1 5 0 . 4 9 6 0 . 4 8 4 0 . 4 6 1 0 . 4 2 4 pore volume rrilST-rH pore voL Apore volume 2 1 4 . 0 7 0 1 9 3 . 7 6 0 1 6 8 . 1 8 0 1 5 1 . 6 8 0 1 3 5 . 8 1 0 1 2 2 . 0 8 0 1 1 5 . 3 3 0 1 0 9 . 6 2 0 1 0 2 . 8 3 0 9 3 . 1 4 0 8 1 . 7 0 7 7 4 . 7 4 6 2 1 1 . 7 5 3 1 2 6 . B 4 1 8 1 . 5 4 2 5 8 . 0 6 2 4 5 . 8 8 5 3 6 . 5 5 0 3 0 . 8 7 4 2 7 . 7 6 8 2 5 . 9 6 4 2 5 . 1 4 8 2 4 . 2 9 4 2 2 . 9 3 1 2 . 9 0 2 5 . 5 4 9 1 0 . 5 6 7 9 . 2 1 1 1 0 . 7 1 6 1 1 . 1 3 7 6 . 063 5 . 6 7 6 8 . 2 2 7 1 2 . 6 2 5 1 4 . 8 9 2 8 . 2 8 2 2 . 9 0 2 8 . 4 5 1 1 9 . 0 1 8 2 8 . 2 2 9 3 8 . 9 4 5 5 0 . 0 8 2 5 6 . 1 4 5 6 1 . 8 2 1 7 0 . 0 4 8 8 2 . 6 7 2 9 7 . 5 6 4 1 0 5 . 8 4 6 1 9 . 8 2 4 2 2 . 7 0 4 2 7 . 7 9 5 1 7 . 2 5 2 1 5 . 8 6 2 1 3 . 1 3 1 1 9 . 8 2 4 4 2 . 5 2 8 7 0 . 3 2 3 8 7 . 5 7 5 1 0 3 . 4 3 7 1 1 6 . 5 6 8 0 . 1 7 5 7 5 2 0 . 3 9 8 1 0 3 0 . 8 2 8 0 2 0 1 . 2 8 6 3 1 7 1 . 4 4 6 9 4 0 1 . 7 0 3 5 4 4 6 . 0 3 8 5 . 0 8 4 6 . 8 9 0 1 0 . 2 4 2 1 1 . 6 7 0 6 . 1 2 6 1 2 2 . 6 0 6 1 2 7 . 6 9 0 1 3 4 . 5 8 1 1 4 4 . 8 2 2 1 5 6 . 4 9 2 1 6 2 . 6 1 8 1 . 6 5 7 2 0 3 1 . 9 7 8 2 6 7 6 . 6 4 6 1 0 3 1 7 . 1 9 6 5 1 6 1 0 . 4 8 6 2 5 7 3 . 7 9 6 5 6 2 separation A pore *TM ; sum of pore, are* iq-m/fr pore sum of -™ ; .YoM-nt! pore vol &»»» 0 . 8 2 4 3 . 0 1 3 8 5 . 0 8 7 0 . 0 7 7 0 . 0 7 7 0 * 2 1 2 0 . 2 1 2 0 . 4 0 6 1 (27 0 . 7 5 4 2 . 9 3 2 5 9 . 3 2 5 0 . 0 5 1 ' 0 . 1 2 6 0 . 0 9 7 0 . 3 0 9 0 . 0 0 3 . 80 0 . 6 6 2 2 . 8 2 8 4 5 . 0 0 4 0 . 0 8 5 0 . 2 1 3 0 . 1 2 4 .. P , A U - . 0 . 0 X 1 4 2 * 0 . 6 1 1 2 . 6 0 4 3 6 . 2 5 5 0 . 0 1 6 0 . 2 3 0 0 . 0 1 9 0 . 4 3 2 0 . 0 0 2 89 0 . 5 6 1 2 . 7 3 0 3 1 . 0 1 9 0 . 0 8 6 0 . 3 1 6 0 . 0 8 6 0 . 5 3 6 0 . 0 2 3 0 . 5 1 7 ' 2 . 6 8 6 2 7 . 8 8 6 6 . 0 5 3 0 . 3 6 9 0 . 0 4 8 0 . 5 8 6 0 . 0 1 8 • 5 0 . 4 7 7 2 . 4 1 3 2 5 . 5 4 3 0 . 4 0 6 0 . 7 7 3 0 . 3 3 4 0 . 9 2 0 0 . 1 6 1 4 l 0 . 4 4 5 . 2 . 0 8 3 2 3 . 7 6 6 0 . 5 2 1 1 . 2 9 6 0 . 4 0 0 1 . 3 2 0 0 . 2 6 8 ! 3 5 0 . 4 0 5 1 . 6 9 7 2 2 . 1 8 7 . 0 . 2 9 0 _ 1 . 5 8 6 4 . 2 0 7 . . . 1*52 . 7- 0 ,124 0 . 3 6 8 1 . 8 0 9 2 0 . 6 6 0 0 . 1 2 6 1 . 7 1 2 0 . 0 8 4 1 .611 0 . 0 6 0 TO PULP BEATEN I MINUTE —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0 . 6 6 6 1 6 8 . 5 7 1 1 0 7 . 2 6 6 7 . 6 8 5 7 . 6 8 5 2 6 . 5 9 1 2 6 . 5 9 1 0 . 6 6 9 1 3 6 ' 0 . 8 1 8 1 5 2 . 0 2 5 7 6 . 8 1 9 8 . 0 3 7 1 5 . 7 2 2 1 9 . 9 1 6 4 6 . 5 0 7 0 . 9 4 1 3 9 3 0 . 7 5 4 1 3 6 . 2 0 6 5 8 . 2 5 7 9 . 7 1 2 2 5 . 4 3 4 1 8 . 2 5 1 6 4 . 7 5 8 1 . 1 4 3 0 6 0 0 . 6 7 1 1 2 1 . 9 3 0 4 4 . 3 5 6 1 0 . 8 7 4 3 6 . 3 0 8 1 5 . 5 5 9 . 8 0 . 3 1 7 1 . 3 1 4 5 7 7 0 . 5 B 2 1 1 0 . 8 6 1 3 4 . 5 4 9 1 0 . 1 0 5 4 6 . 4 1 3 1 1 . 2 6 2 9 1 . 5 7 9 1 . 4 4 7 9 5 5 0 . 4 9 3 9 7 . 5 4 0 2 7 . 9 7 7 1 5 . 3 0 3 6 1 . 7 1 6 1 3 . 8 1 1 1 0 5 . 3 9 0 2 . 5 7 3 3 6 5 0 . 4 B 2 8 6 . 4 8 1 2 5 . 0 2 1 1 6 . 0 7 5 7 7 . 7 9 1 1 2 . 9 7 5 1 1 8 . 3 6 4 2 3 . 7 9 5 4 1 0 0 . 4 3 6 7 1 . 4 1 0 2 3 . 6 9 7 2 1 . 4 5 1 9 9 . 2 4 2 1 6 . 3 9 6 1 3 4 . 7 6 2 7 . 8 0 2 4 8 7 0 . 3 8 2 6 4 . 6 9 3 2 1 . 5 6 6 8 . 2 2 3 1 0 7 . 4 6 6 5 . 7 2 1 1 4 0 . 4 6 3 2 . 6 4 7 8 4 1 0 . 3 1 5 5 8 . 6 4 7 1 9 . 3 1 5 6 . 8 8 4 1 1 4 . 3 4 9 4 . 2 8 9 1 4 4 . 7 7 2 1 . 8 3 2 1 7 7 UNBEATEN PULP SHEETS WITH 5.5% MOISTURE PRIOR TO SOLVENT EXCHANGE ORYIIWj 0 . 9 0 2 4 . 740 1 8 7 . 3 6 9 0 . 0 8 0 0 . 0 8 0 0.481 0.481 0.003392 0 . 8 4 0 4 . 5 4 8 9 5 . 5 4 0 0 . 0 6 7 0 . 1 4 7 04207 0.667 0.004926 0 . 7 6 5 4 . 4 2 9 6 3 . 4 7 8 0 . 0 5 6 0 . 2 0 5 0 . 1 1 9 .. . . P J 9 » 0.008352 0 . 6 7 1 4 . 3 1 0 4 5 . 4 3 0 0 . 0 7 9 0.264 0 . 1 1 6 0.922 0.0009*0 0 . 6 0 5 4 . 2 0 9 3 5 . 4 3 7 0 . 0 8 7 0 . 3 7 1 r 0 . 1 0 0 1.012 0.01*229 0 . 5 4 0 4 . 107 3 0 . 1 3 3 0 . 1 0 3 0 . 4 7 4 0 . 1 0 0 1.122 0.0223*3 0 . 4 9 5 3 . 7 7 4 2 6 . 6 6 3 0 . 4 1 4 0 .688 0 . 3 5 6 1.476 041*314* 0 . 4 6 9 3 . 3 5 6 2 4 . 7 8 4 0 . 5 6 1 1 .449 0 . 449 1.92* 0.353186 0 . 4 3 7 2 . B 9 4 2 3 . 4 2 1 0 . 6 4 4 2 .092 0 . 4 8 6 2.413 0.333940 0 . 4 0 4 2 . 6 7 7 2 2 . 0 1 2 0 . 2 9 5 2 .368 0.210 2.822 0.1*4107 0 . 3 5 3 2 . 4 7 B 2 0 . 3 7 4 0 . 2 5 9 2 . 6 4 7 0 . 1 7 1 2.793 0.068993 0 . 2 8 2 2 . 2 1 6 1 8 . 2 5 7 0 . 3 6 9 3 . 0 1 6 0 . 2 1 8 3.010 0»0«3*TI PULP BEATEN 5 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION; UNBEATEN PULP SHEETS WITH H.4% MOISTURE PRIOR TO SOLVENT EXCHANGE ORYING 0 . 8 4 9 1 5 8 . 9 5 2 1 0 5 . 7 5 0 1 5 . 5 5 4 1 5 . 5 9 4 5 3 . 0 5 9 9 3 . 0 5 9 0 . 9 7 2 9 9 4 0 . 7 7 8 1 3 4 . 2 1 0 66 885 1 3 . 3 3 0 2 8 . 8 8 4 2 6 . 7 6 0 8 1 . 8 1 9 1 . 2 3 9 7 5 2 0 . 6 7 7 1 1 3 . 1 2 6 47 208 1 4 . 9 6 9 4 3 . 6 5 3 2 2 . 7 9 3 1 0 4 . 6 1 4 1 . 4 1 0 9 6 8 0 . 5 8 6 9 9 . 9 4 6 35 119 1 1 . 6 7 5 5 5 . 5 2 8 1 3 . 2 2 7 1 1 7 . 6 4 1 1 . 6 4 9 0 1 3 0 . 5 4 5 . 9 4 . 7 7 0 29 651 5 . 0 5 6 6 0 . 5 6 4 4 . 8 3 6 1 2 2 . 6 7 7 1 . 6 5 8 8 7 1 0 . 4 9 5 8 8 , 7 3 5 26 792 6 . 5 5 0 6 7 . 1 3 3 9 . 6 6 0 1 2 8 . 3 3 7 2 . 0 1 8 4 9 0 0 . 9 7 1 1 4 . 7 4 5 0 . 4 7 2 0 . 4 6 0 0 . 4 2 9 0 . 3 9 4 0 . 3 5 9 7 6 . 8 6 5 7 2 . 5 4 7 6 6 . 6 1 2 6 2 . 7 5 5 5 9 . 5 7 5 2 4 . B 2 9 2 3 . 9 9 0 2 3 . 0 2 7 2 1 . 6 4 0 2 0 . 2 9 7 1 6 . 7 6 5 6 . 0 4 8 7 . 8 1 2 4 . 4 6 6 3 . 5 4 4 8 3 . 8 9 8 8 9 . 9 4 6 9 7 . 7 5 7 1 0 2 . 2 2 4 1 0 5 . 7 6 8 1 3 . 4 2 8 4 . 6 8 0 5 . 8 0 3 3 . 1 1 6 2 . 3 2 1 1 4 1 . 7 6 5 1 4 6 . 4 4 5 1,32.247 1 3 5 . 3 6 5 1 5 7 . 6 8 6 1 1 . 9 8 1 2 5 3 8 . 3 7 9 1 7 2 4 . 2 4 5 2 2 5 2 . 2 1 4 9 1 9 1 . 8 1 6 6 4 1 0 . 9 1 3 0 . 8 3 3 0 . 7 6 4 0 . 6 7 3 0 . 5 9 6 0 . 5 4 2 0 . 5 0 4 0 . 4 7 7 0 . 4 5 8 0 . 4 3 9 0 . 3 9 3 0 . 3 4 4 h . O 6 0 1 3 . 7 3 5 1 3 . 5 8 5 1 3 . 2 7 5 1 3 . 0 3 9 1 2 . 2 2 9 1 1 . 0 8 2 9 . 8 4 3 9 . 0 6 1 2 4 7 . 1 0 8 1 0 0 . 2 8 1 6 1 . 8 3 2 4 5 . 4 4 9 3 3 . 1 7 5 2 9 . 8 3 6 0 . 2 9 1 2 6 . 9 4 9 2 5 . 1 8 3 . 2 4 . 0 5 8 2 3 . 1 9 1 2 1 . 8 3 6 2 0 . 0 0 7 0 . 0 9 6 0 . 1 0 5 0 . 0 7 3 0 . 2 1 4 0 . 2 0 3 0 . 1 9 1 0 . 7 4 6 1 . 4 8 5 1 . 6 7 2 1 . 0 6 6 1 . 1 3 3 0 . 8 8 5 0 . 0 9 6 0 . 2 0 1 0 . 2 7 4 0 . 4 8 6 0 . 6 9 1 0 . 8 8 2 1 . 6 2 8 3 . 1 1 4 4 . 7 8 * 5 . 8 5 2 6 . 9 8 3 7 . 8 7 0 0.764 0.339 0.146 . 0.314 0.231 0.164 0.649 1.207 1.298 0.798 0.798 0.571 6.7*4 1.103 JL 2*3 1.9*3 LT94 1.97T 1 8 . 2 4 7 0 . 9 3 6 8 . 8 2 6 0 . 5 * 3 2.62* 3.633 5.130 5.426 6.72* 7.297 0.003238 0.003876 0.,007921 0.0232lT 0.032929 0.050559 6.2*724* 0.893722 1.444098. 0.453T80 0.42379* 0.320402 7.8*6" "6.32*26* PULP BEATEN 9 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION, 0 . 9 0 3 1 5 4 . 3 0 4 0 . B 3 6 1 2 5 . 3 3 9 9 5 . 2 8 2 1 1 . 9 3 2 1 1 . 9 3 2 3 6 . 6 7 5 . 3 6 . 6 7 9 0 . 6 3 9 5 7 9 0 . 7 2 9 1 0 2 . 9 3 1 5 9 . 6 9 6 1 3 . 6 7 1 2 3 . 6 0 3 2 6 . 3 2 6 6 3 . 0 0 1 0 . 9 5 7 * 4 8 0 . 6 2 2 9 0 . 4 9 6 3 9 . 8 5 5 1 0 . 2 4 5 3 5 . 8 4 8 1 3 . 1 7 1 7 6 . 1 7 2 1 . 0 8 0 3 1 5 0 . 5 3 3 8 3 . 5 9 6 3 0 . 6 3 4 6 . 6 2 7 4 2 . 4 7 5 6 . 5 4 8 8 2 . 7 2 1 1 . 0 4 7 9 6 4 0 . 4 9 3 8 0 . 5 9 6 2 6 . 3 9 9 3 . 2 5 8 > 4 5 . 7 3 2 2 . 7 7 4 8 9 . 4 9 9 1 . 2 4 8 1 1 0 0 . 4 6 7 6 9 . 8 8 0 2 4 . 6 5 9 1 5 . 6 9 7 6 1 . 4 2 9 1 2 . 4 8 6 9 7 . 9 8 1 9 . 9 3 5 5 4 2 0 . 4 3 9 6 2 . 1 5 9 2 3 . 3 9 9 1 1 . 3 6 8 7 2 . 7 9 7 8 . 5 8 1 1 0 6 . 5 6 1 6 . 7 9 7 9 7 7 0 . 4 0 7 5 8 . 3 4 4 2 2 . 0 9 9 5 . 0 2 7 7 7 . 8 2 4 3 . 3 8 4 1 1 0 . 1 4 5 2 . 6 7 6 6 9 3 0 . 3 7 2 5 5 . 6 0 1 2 0 . 7 7 8 3 . 2 6 8 8 1 . 0 9 2 2 . 1 9 1 1 1 2 . 3 3 6 1 . 6 6 1 0 8 9 0 . 2 8 1 4 8 . 9 4 0 1 8 . 6 0 1 8 . 3 8 9 8 9 . 4 8 1 5 . 0 3 4 1 1 7 . 3 6 9 1 . 6 4 9 7 3 4 UNBEATEN PULP SHEETS WITH 33j6% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING] 0 . 9 1 5 1 2 2 . 4 9 4 _ 0 . 8 3 6 0 . 7 6 5 0 . 7 1 2 0 . 6 3 8 0 . 5 7 5 0 . 5 3 1 0 . 4 9 2 0 . 4 6 0 0 . 4 6 6 0 . 3 9 7 0 . 3 4 7 0 . 2 7 4 1 1 4 . 3 2 6 1 0 3 . 1 3 1 9 8 . 1 3 2 8 9 . 6 5 2 8 3 . 2 7 4 7 8 . 9 5 7 _ 1 0 2 . 7 2 2 6 2 . 4 4 5 4 7 . 9 1 8 3 9 . 3 4 * 3 2 . 6 8 6 2 8 . 7 8 3 7 1 . 2 5 6 6 2 . 7 8 4 5 5 . 3 8 6 4 6 . 3 3 3 4 2 , 6 1 9 3 7 . 6 9 6 2 6 . 3 3 9 2 4 . 9 7 5 2 4 . 3 2 6 2 2 . 5 1 8 2 0 . 1 4 5 1 6 . 0 4 8 3 . 0 6 2 5 . 474 5 . 2 5 0 7 . 4 8 3 6 . 4 8 6 4 . 8 5 3 3 . 0 6 2 8 . 3 3 6 1 3 . 7 6 6 2 1 . 2 6 8 2 7 . 7 5 4 3 2 . 6 0 7 1 0 . 0 8 7 1 2 . 2 3 B 1 0 . 7 6 6 1 2 . 0 3 0 4 . 3 4 3 5 . 9 4 1 4 2 . 6 9 4 5 4 . 9 3 2 6 5 . 6 9 8 7 7 . 7 2 8 8 2 . 0 7 0 8 8 . 0 1 1 1 0 . 1 4 * 1 1 . 0 2 * 8 . 1 1 5 9 . 4 9 7 6 . 8 3 9 4 . 5 0 6 8 . 5 6 9 9 . 6 6 0 8 . 4 4 8 8 . 7 3 8 2 . 8 2 2 3 . 4 5 9 10.14* 21.173 29.288 36.785 45.624 50.130 58.699 68.556 77 .00* 65.745 68.5*6 92.025 0.1*8126 0.545702 0.9i722*_ 1.144*52 1.36293* 1.613*30 4.070622 16.059692 12.34130* 2.961400 1.5534*7 1.4560*2 PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0 . 9 4 8 1 9 1 . 3 1 4 0 . 8 S B 1 5 1 . 0 4 8 1 5 6 . 1 1 8 9 . 392 9 . 3 9 2 4 7 . 3 0 1 4 7 . 3 0 1 0 . 4 4 6 0 9 4 0 . 8 2 4 1 2 7 . 2 5 5 8 5 . 6 3 2 9 . 5 6 1 1 8 . 9 5 4 2 6 . 4 1 2 7 3 . 7 1 3 0 . 7 5 5 9 4 1 0 . 6 9 1 1 0 0 . 9 6 5 5 4 . 4 8 9 1 5 . 5 3 9 3 4 . 4 9 3 2 7 . 3 1 3 1 0 1 . 0 2 6 0 . 9 9 8 7 9 2 0 . 6 1 0 9 1 . 0 8 2 3 6 . 7 8 0 7 . 820 4 2 . 3 1 3 9 . 2 7 8 1 1 0 . 3 0 4 1 . 1 4 9 4 2 6 0 . 5 6 0 B 5 . 7 4 9 3 0 . 9 6 5 4 . 8 5 5 4 7 . 1 6 7 4 . 6 4 9 1 1 5 . 1 5 3 1 . 3 6 2 7 2 9 0 . 5 1 7 8 1 . 6 7 2 2 7 . 8 9 2 3 . 9 6 4 5 1 . 1 3 1 3 . 5 6 7 1 1 8 . 7 2 0 1 . 3 7 7 7 2 6 0 . 4 7 4 6 9 . 4 4 3 2 5 . 4 7 1 1 5 . 4 4 1 6 6 . 5 7 2 1 2 . 6 8 7 1 3 1 . 4 0 6 5 . 6 3 2 6 4 1 0 . 4 4 9 6 4 . 3 6 8 2 3 . 7 7 1 6 . 4 7 7 7 3 . 0 4 9 4 . 9 6 7 1 3 6 . 3 7 3 4 . 3 2 4 2 7 1 0 . 4 2 1 6 0 . 9 2 3 2 2 . 5 9 9 4 . 1 2 5 7 7 . 1 7 4 3 . 0 0 7 1 3 9 . 3 8 0 2 . 5 1 5 9 9 7 0 . 3 9 2 5 8 . 0 8 7 2 1 . 4 3 7 3 . 3 1 6 8 0 . 4 8 9 2 . 2 9 3 1 4 1 . 6 7 3 2 . 0 3 0 7 7 2 0 . 3 5 8 5 5 . 1 9 1 2 0 . 2 3 3 3 . 3 0 3 8 3 . 7 9 3 2 . 1 5 6 1 4 3 . 8 2 8 1 . 6 8 6 6 P 6 -229-! TABLE 2 CONTINUED cnihmcAL PORE MODEL; CYLINDRICAL PORE MODEL' _jW6EAT£W PULP — SOLVENT EXCHANG£ DRIED FROM WATER SUSPENSION UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE DRYING port vol -0 . 3 8 6 7.043699" 3.2813831 3.213002. 0.887 0.824 0.754 0.682 0.611 0.561 0.517 0.477 0.449 0.405 0.368 diam. of port 75.009 50.706 37.400 29.388 .24.653 2.6B6 21.B50 2.413 19.772 2.083 18.206 1.897 16.826 1.809 19.500 3.177 3.013 2.932 2.828 2.804 .730 W r y * 0.097 . 0.070 . 0.133 04 022 0.162 0.101 0.886 1.182 0.634 0.227 tun of pore am-0.097 0.167 .0.301 0.585 1.471 2.693 3.287 3.314 \dumr. rrt.JST.EVV 0.233 0.115 0.161 0.021 0.129 - 0.071 0.565 ' 0.694 0.344 0.113 port vol 0.235 0.350 0.511 0.532 0.660 0.731 1.296 1.990 2.335 2.448 ^ port volumt £port Uzt 0.007392 0.006832 0.016373 . 0.003346 0.039267 0.030396 0.309792 0.531795 . 0.236660 0.094998 fPULP BEATEN j MINUTE —SC^VENT^EXI^Aft^ JRlED FROM WATER SUSPENSION 0 . 9 1 1 JO. 8 6 6 ! 0 . 7 5 4 0 . 6 7 1 0 . 4 9 3 ; 0 . 4 8 2 J J U 4 3 6 _ : 0 . 382 0 . 3 1 3 1 8 9 . 8 3 9 1 6 8 . 5 7 1 - 1 4 2 . 0 2 5 -1 3 6 . 2 0 6 1 2 1 . 9 3 0 " 0 . 8 6 1 97.340 86.481 _11.410 _ 64.693 58.647 96.134 9.289 9.289 67.149. . 10.554 . 19.842 49.703 14.062 33.903 36.806 17:585 51.490 27.846 1 6.02 0 69.309 2 1 - 9 3 8 3 1 . 4 0 6 100.916~ 19.309 36.367 437.263 ...IB.147... ..48.602 169.965 .16.287t 14.391 200.356 14.344 1 6.799 209.153 . 26.805 .22*060 22.546 20.680 16.186 22.226 22.652 ..28.498 7.561 i i m 4.071 2B.805 51.666 74.212 95.091 111.278 133.503 156.156 184.694 192.213 19&.266 0.758395 1.143702 1.512766 1.917999 2.299764, 4.652602 47.125031 15.461434 4.027889 2.025726 UNBEATEN PULP SHEETS WITH 5.3% MOISTURE PRIOR JO SOLVENT EXCHANGE DRYING] .0.959 0.902 0.840 0.765 0.671 O.M)5 5.158 4.740 4.348 • 4.429 4.310 . 4.209 173.578 64.963 54.605 37.823 28.644 0.096 0.092 0.084 0.139 0.171 0.096 0.187 0.276 . 0.416 0.586 0.536 0.251 0.157 0.170 0.158' 0.936 0.787 0.944 1.114 • 1.271 0.003904 0.006291 0.007535 0.013295 0.0282611 0.540 0.495 0.469 ' • 0.437 0.404 0.351 4.107 3.774 3.356 2.894 2.677 2.478 23.B60 20.763 19.101 17.904 16.674 15.254 0.217 0.997 1.403 1.645 0.692 0.511 0.603 1.800 3.203 4.848 5.540 6.051 0.167 0.667 0.865 0.950 0.372 0.292 1.438 2.106 2.970 3i920 4.292 4.544 0.041863 0.302630 0.772381 0.744710 0.314060 0.152034 0.262 2.216 13.436 0.773 6.624 0.335 4.879 0.169629 IPULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATERSUSPENSION ,0.915 0.849 foT677. .0.348 0.545 0.499 !0.472 ..HV460 _ 0.429 0.394 (0.359_ 2 0 1 . 6 5 3 1 3 8 . 9 5 2 1134. 210 _. 1 1 3 . 1 2 6 76.865 _T2»5AI„ 66.612 62.753 39.575 UNBEATEN PULP SHSETS W]TH 14.4% MOISTUREPRIOR TO SOLVENT EXCHANGE DRYING 9 4 . 7 3 7 ... 37.8Q1„ 3 9 . 4 9 2 2 8 . 3 6 5 33 ,42 ,5 2 0 . 6 7 8 1 9 . 1 4 1 _ ie . .402„ 1 7 . 5 5 9 1 6 . 3 5 0 1 5 . 1 8 6 19.379 .13.674... 24.076 20.708 ? tPW 12.666 36.179 ..13.488._. 16.510 7.642 5.282 19.379 .-38,Q53_. 62.129 82.636 " « « 9 104.603 142.764 .156.272.. 172.782 160.424 185.707 59.222 59. „34»ei9 94, 30.639 124, 16.946 143. 6.664 150. 8.344 159. 23.374 182. . . 8 .007 , 190. 9.351 199. 4.031 203. _ 2.586 206. .222 041 661 626 490 034 606 614 966 996 584 1.137102: 1.396022 2.034814 2.607203 2.632114 3.439166 23.677365 16.324631i 7.822379 3.294692 2.3464461 "0.971 0.913 0.833 0.764 0.673 0.542 0.504 0.477. 0.458 0.439 0.393 14.745 14.060 13.735 13.385 13.273 13.039 12.850 12.229 11.082 9.843 9.061 231.900 69,540 53.033 3 7,. 620 28.409 23.610 21.016 19.453 18.462 17.702 _ 1 6 . 5 2 ; " 0.119 0.149 0.116 0.399 0.412 0.414 1.825 3.795 4.366 2.748 -2.712 0.115 . 0.269 0.380 0.779 1.191 1.606 3.430 7.225 11.591 14.339 17.092 16.990 21.111 0.B64 0.431 0.198 0.486 0.376 0.315 1.237 •2.381 2.600 1.569 1.446 0.864 1.295 1.493 1.979 2.357 2.672 3.909 6.291 6.891 10.460 11.906 0.003799 0.007841 0.011008 0.038987 0.099924 0.0970401 0.638647 . 1.999609' 9.294147 2.144168 _0.886983 6.607625 0.620469 (PULP BEATEN a MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 6 9 . 8 8 0 6 2 . 1 5 9 3 8 . 1 4 4 . _ 5 5 . 6 0 1 4 6 . 9 4 0 64.724 14.930 51.094 I 0 U 3 7 „ 32.686 17.176 24.315 11.846 20.529 6 .Q4^ 18.991 35.440 17.883 25.696 . 16.749 I_9,B37 15.602 9.161 ' 13.734 14.075 14.930 .35 .067_ 92.264 64.112 70.136 105.596 131.251 .141.068 146.249 160.324 1.805 1.223 1.110 1.293 ,002 40.805 74.027 92.138 101.431-103.433 ,.711 127.144 1.802 141.946 1.315 147.260 :.598 149.858 .236 156.093 0.981270 1.293842 1.625899 1.658458 2.032911 19.624191 13.386587 4.357436 2.303163 2.39099-6 UNBEATEN PULP SHEETS WITH 33jS% MOISTURE PRIOR TO-SOLVENT" EXCHANGE DRYING T.913 • 122.494 , . * "~ " ''" ' ~ _ ' •0.836 114.326 91.877 3.694 3.894 11.541 11.341 0.200457 0.765 103.131 53.630 7.918 _ 11.812 13.697 25.238 0.723944 0.712 98.132 40.082 8.228 20.040 10*639 35.877. 1.301324 0.638" 89.632 32.206 12.926 32.965 13.42B 49.306 1.772614 0.531 78.957, 22.650 9.397 54.367 6.866 66.301 2.755214) 0.492 71.256 20.472 21.752 76.119 14.364 80.665 7.704779 0.480 62.7B4 19.269 27.642 103.961 17.306 97.971 31.9806811 0.466 55.386 IB.698 24.555 126.515 14.810 112.761 24.606400' 0.397 46.333 17.118 24.776, 153.292 13.681 126.463 9.349516 0.347 42.619 15.056 5.805 159.097 2.820 129.282 1.799486 3 . 1 3 9 1 3 2 . 4 2 1 1 . 9 3 1 1 3 2 (NjLP BEATEN N> MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0 7 9 4 8 1 9 1 . 3 1 4 '• ' '—" \ " T - O . m 1 3 1 . 0 4 9 1 4 3 . 2 . 2 1 1 . 4 1 . 1 1 . 4 1 9 3 Z . T T 1 3 2 . 7 7 1 0 . 3 1 9 7 2 3 :•••*£*-—;JJ>233„„„75.330___ U . 1 9 J 2 4 . 4 1 4 3 2 . 1 5 0 „ _ 6 4 . 9 2 1 0 . 9 7 0 1 4 6 :0 .691 1 0 0 . 9 6 5 4 6 . 2 4 9 , 2 6 . 0 6 8 9 0 . 7 0 2 3 B . 9 2 0 1 2 3 . 8 4 1 ' 1 . 9 3 0 9 1 0 ' : 0 . 6 l 0 9 1 . 0 8 2 2 9 . 8 6 9 1 4 . 1 2 0 . 6 4 . 8 2 1 1 3 . 6 0 9 1 1 7 . 4 4 6 1 . 3 9 4 3 6 6 ; -J»>4? M ' T W 9 , > 9 | 7 4 . 0 1 2 7 . 2 9 3 1 4 4 . 7 4 0 2 .2636941 6 1 . 6 7 2 2 1 . 8 3 5 7 . 7 0 9 8 1 . 7 2 1 9 . 4 3 9 . 1 9 0 . 1 7 9 2 . 3 5 8 6 5 7 ,0 .474 6 9 . 4 4 3 1 9 . 7 0 8 3 6 . 4 9 1 1 1 6 . 2 1 2 2 3 . 1 9 9 1 7 3 . 3 7 4 11 .6651161 J-*** 6 4 . 3 M _ _ 1 6 . 2 1 0 1 4 . 8 4 7 . — 1 3 3 . 1 0 6 8 . 7 5 1 . ^ 1 0 2 . 1 2 9 8 . 6 6 4 1 3 8 0 . 4 2 1 . 6 0 . 9 2 3 1 7 . 1 6 5 . 8 . 5 6 6 1 4 1 . 6 9 4 4 . 7 5 9 1 8 6 . 8 8 4 4 . 5 6 1 7 8 9 0 . 3 9 2 5 6 . 0 8 7 1 6 . 1 7 3 A 6 . 4 0 9 1 4 8 . 1 0 3 3 . 3 4 3 1 9 0 . 2 2 8 3 . 4 1 0 6 0 7 0 . 3 3 6 5 3 . 1 9 1 1 S . U L 9 . 7 6 * . 1 9 3 . 3 6 9 . 2 . 8 2 4 1 9 3 . 0 5 2 2 . 6 6 0 5 3 3 -230-TABLE 3= PORE ANALYSIS USING STANDARDIZED ARGON. ISOTHERMS UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0.850 0.800 0.T50 0.700 0.650 •0___Q1. • 0.550 0.500 0.450 0.400 0.380 Q,P370 0.360 0.350 0.340 0.330 0.300 190.000 176.000 164.000 154.000 145.000 -._L37.QI-Q_. .ttparation, A I 113.452 80.045 62.329 51.242 43.546 " . 7 Q f l 5.273 6.082 6.675 6.731 7.018 7.nr .A 130.000 122.000 114.000 106.000 . 102.000 83.000 75.000• 71.000 68.000 62.000 33.274 29.634 26.623 24.075 22.467 21.405 21.001 20.609 20.227 14.492 • B - n q ' i 6.762 8.752 9.587 10.530 5.584 5 .273" 11.355 18.030 24.760 31.778 *A.7«*. 24.230 12.874 6.278 4.629 8.916 7-460 45.548 54.300 63.888 74.418 80.002 port ' ; . . v d i j r n t ; "19.298" 15.703 13.421 11.125 9.859 a__J4.3... turn of • pore v o l r r _ & T % "19.298 " 35.001 48.422 59.547 69.406 7TT94' 110.313 123.187 129.465 134.094 143.010 1 * 0 . 9 6 4 7.258 8.367 8.234 8.17B 4.047 85.206 93.573 101.807 109.985 114.032 ___LB_, __ por* v o l u r m • £por» v z t 07432126 0.708755 1 .010895 1.250404 1 .517764 7fl2a' 3.020 5.606 4-646 135.042 143.764 147.938 150.958 156.564 l h l . P l f l 1.808181 2.560570 2 .990491 3.490779 4.629946 14]R4Q 40.696132 21.868790. 10.814788 7.986792 5.133451 PU^JJEATJUUJjINU^ FRC^ATJR SUSPENSlC^ l PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION • PULP BEATEN fl MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION, 0.850 0.800 0.750 0.700 0.650 •0.550 0.500 0.450 0.400 0.380 0.360 0.350 0.340 0.330 0.300 155.000 144.000 134.000 126.000 118.000 - L l l . i m C L . 105.000 99 . 000 93.000 87.000 84.500 113.452 80.045 62.329 51.242 43.546 37 ,70ft 78.000 68.000 64.000 61.000 55.000 33.274 29.634 26.623 24.075 22.467 .820 4.032 4.780 5.571 5.385 • 6.268 -160 21.405 21.001 20.609 20.227 19.492 t fl , n m 5.815 6.497 7.120 7.829 3.372 4.032 8.813 14.384 19.769 26.037 -09-8.736 16.389 6.425 4.778 9.383 6_B68 -. 38.012 44.509 51.628 59.457 62.829 -JL3.4-14.757 12.344 11.201 B.901 8.805 7.510 14.757 27.101 38.302 47.203 56.008 63.518 72.890 B9.279 95.704 100.482 109.865 ..116 .733 6.241 6.210 6. 114 6.080 2.444 . — 0 . 9 3 2 6.032 11.103 4.271 3.118 . 5.900 69.759 75.969 82.084 88.164 90.608 .540 97.572 108.675 112.946 116.064 121.964 125,37 _• 0.330450: 0.557118 0.843714 1.000407 1 .355575 -1.496844.1 1 .554899! 1.900644 2 .220694, 2.595457 2.795746 I 2.22001,9 ; 14.744 889 27.839462 11.068015 8.245047 5.402268 2.355616 0.850 0.800 0.750 0.700 0.650 0.600 0.550 0.500 0.450 0.400 0.380 0.360 0.350 0.340 0.330 0.300 126.000 119.000 113.000 107.000 102.000 aa.ooa.. 94.000 90.000 87.000 83.000 80.500 79_non 113.452 80.045 62.329 51.242 43.546 - 1 8 0 -77.000 71.000 61.500 58.000 53.000 -_5J.00Q— 33.274 29.634 26.623 24.075 22.467 2.792 3.038 3.335 4.057 3.906 -3-684 • 21.405 21.001 -20.609 20.227 19.492 3.892 4.346 -3.436 5.259 3.572 - ? ? 9 9 . 1 * 5 -20.612 3.085 9.821 -15-935 . 5.750 7.900 , 7 -ATA 24.504 28.850 - 32.286 -37.544 41.116 43.3__.., 46.431 56.252 - .72-187-77.937 85.836 93-3X2 . 10.217 7.844 — W T O * — 6.706 5.487 •4.247 4.177 4.154 — 2 . 9 3 1 -4.084 . 2.589 \ .130 6.653 ~L0.594 3.752 4.967 A. -3A* 1 0 . 2 1 7 0 . 2 2 8 7 7 3 1 6 . 0 6 1 0 . 3 5 4 0 4 3 - 2 4 . ^ 6 7 — 0 , 6 . 3 1 4 2 3 1 . 4 7 3 6 . 7 5 3 7 1 5 3 6 , 9 6 0 0 . 8 4 4 7 3 9 - 6 1 . 2 0 7 . — 0 . 6 4 6 6 0 4 4 5 . 3 8 4 1 . 0 4 0 6 9 1 4 9 . 5 3 9 1 . 2 7 1 5 9 9 - 5 2 . 4 8 9 1 . 0 7 1 6 0 1 5 6 . 5 7 3 3 9 . 1 6 2 .7^1 6 2 . 8 6 2 6 9 . 5 1 9 16. 1 0 9 - 2 7 . 8 3 . 8 6 0 . 9 , 6 8 . 8 2 7 4, . 7 4 3 3 0 7 1 .961574 2 0 7 5 5 5 6 6 2 T 8 5 .449921 -.921124, 5 4 8 2 6 5 PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0.850 0.800 0.750 0.700 0.650 -0.600— 136.000 126.000 118.000 110.000 103.000 . 9I_DflO_ 113.4S_ 60.045 62.329 51.242 43.546 »7,70ft 3.412. 4.351 4.447 5.409 5.481 3.412 7.763 12.210 17.619 23.100 2ft.__.B-. 12.487 11.234 8.942 8.942 7.698 -__.A21-12.487 23.721 32.662 41.604 49.303 0.279611' 0.507019 0 . 673 344 1.004974 1.185202 1. _anna?' 0.530 0.500 0.450 0.400 0.380 n.^7n 92.000 86.000 81.000 77.000 75.000 7*_f>i-n 33.274 29.634 26.623 24.075 22.467 ______ 4 .818 6.581 5.883 5.013 2.669 7 -Q7Q 33.186 39.767 45.690 50.663 53.332 5.171 6.291 5.052 3.893 1.935 ? - t l 4 7 60.895 67.187 72.239 76.132 78.067 .288375 1.929439 1 .834891 1.661850, 2.213162 4 . 9 9 ^ H _ f .360 0.350 0.340 0.330 0.300 Q - " 0 69.000 64.000 96.500 56.000 51.000 4h.nm. 21.405 21.001 20.609 20.227 19.492 l A - f t O t 6.309 8.075 9.060 3.982 7.819 7.331 .62.620 70.695 79.756 83.738 91.557 ,. .9B_jaa_ 4.356 5.471 6.023 2.598 4.916 4.?79 84.520 89.991 96.014 98.612 103.528 __07.aQJ_ 10.649177 13.716990 15.607324, 6.870851 4.501869 7 - H - l . n V UNBEATEN PULP SHEETS WITH 5.3% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING i UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT PfCHANGE DRY-MO .6.650 , 5.380 113.452 0.037 0.037 0.136 0.136 0.003050. 0.850 3.500 113.452 0.022 0.022 0.079 0.079 0.00frf79> 0.800 5.290 80.045 0.039 0.076 0. 101 0.237 0.004549 0.800 , 3.420 80.045 0.035 0.057 0,090 0 . 1 7 0 0.0040681 0.750 5.220 , 62.329 0.039 0.115 0.078 • 0.315 6.'005877 0.750 3.350 6 2 . 3 2 9 . ...-0*039..- 0-096 — . _ ~ o ; o 7 9 _ 0.246. O.005<16 0.700 5.140 91.242 0.054 0. 169 ,0.090 0.405 0.010065 0.700 3.290. 31.242 0.041 0.136 0.067 0 . 3 1 5 0.007529 0.650 5.050 • 43.546 0.071 0.240 0. 100 0.509 0.019403' 0.650 3.230 . 43,546 0.047 0 . 1 8 3 0.066 0.381 0 .010202 ft *,nrt _ . 9 h n »7 . i o n ft. nft i n i n n nan n n l ifif] ft n .Aftft * . i»\n »?.7an ft_.__. n.nil ft. _*.•>. ft.nl«?7ft 0.550 4.860 33.274 0. 101 0.422 0.108 0.711 0.026949 0.950 3.090 33.274 0.070 0.316 0.075 0.333 0 * 0 1 6 7 6 2 0.500 4.740 29.634 0.136 0.558 0.130 0.841 0.039751; 0.500 3.010 29.634 0.090 0.406 0 . 0 6 6 0 . 6 1 9 0*026320 0.450 - 4.610 26.623 • 0.162 0.720 0. 139 0.480 0.050496, 0.450 2.920 26.623 -.0.112 _ 0-518 . . . - . 0*096- , 0 -713-0.400 4.440 24.075 ' 0.235 0.953 0.183" 1.163 0.078067) • 0.400 2.820 24.075 0 . 1 3 7 0.635 0.106 0.821 0 .045344 0.380 4.340 22.467 0. 146 1.103 0.107 1.270 0.122599 0.380 2.760 22.467 0.088 0.743 0.064 0 .865 0*072942 n . M _ -jA.n 3 1 n.ft n . ]•}«. i 3KQ n 1 i n ft 5*1^^7 0.^70 p _ 7 . n ? 1 . R J f t ft.07T n .H7n n.n«i_ n-«4n ft.'19Q-AN 0.360 4.030 21.405 0.339 1.596 0.234 1.614 0.572136 0.360 2.360 21.405 0.210 1.030 0.143 1.064 0.333679 0.350 3.920 21,001 0.511 - 2.109 0.346 1.960 0.868148 . 0.350 2.300 21.001 0.464 1.493 0.314 1 . 3 9 8 0 .787340 0.340 3.280 20.609 0.740 2.849 0.492 2.452 1.275068! 0.340 2.0B0 .20.609 . 0.366.. -...-1.661 .— — 0 - 2 4 5 — 1*643-. .0 . 6 3 6 2 5 8 -0.330 3.020 20.227 0.438 3.288 0.286 - 2.73B 0.756222 ' 0.330 1.960 20.227 0.200 2.061 0.130 1 . 7 7 3 ;0V344849 0.300 2.630 19,492 0.655 3.943 0.412 . 3.150 0.3 77090 0.300 1.730 19.492 0.349 2.410 0.219 1.993 0 .200721 0.2S0 7 .nan l f l . n s 1 . ft. 1^7 4.4Hft n - i - n i « _ i _ 7 n . ?50 1.51(1 l A . t V ) 1 . 0.40? n . 3 * « , 2.771 -231-TABLE 4: PORE ANALYSIS USING EXPERIMENTAL VALUES OF ARGON ISOTHERMS UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION PULP BEATEN I MINUTE —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 206.214 190.65S 183.564 171.219 157.697 164.204 134.013 123.740 _U'.Sf.m_ 107.930 101.229 91.638 7*.5*3 "0.699 0.878 0.782 0.718 : 0.645 0.581 0.515 0.407 0.376 0.367 0.351 i0.304 • M i l separation, '• A J 219.765 123.049 __?*•«+_ 72.542 56.633 44.760 16.768 31.267 ,27.373 24.530 22.344 21.677 21.148 8 T H sum of port am 2.9U 2.013 _**066 _ 5.503 7.706 9.583 — a .127 9.952 8.396 9.1688 8.878 14.226 24.338 2 .914 4 . 9 2 7 _ 9 . 9 9 3 1 5 . 4 9 6 2 3 . 2 0 2 3 2 . 7 8 5 4 1 . 3 1 2 5 1 . 2 6 4 _ . 5 9 . 6 6 0 6 9 . 3 4 9 "" 7 8 . 2 2 6 9 2 . 4 5 2 1 1 6 . 7 9 0 1 3 5 . 0 0 8 1 4 5 . 5 6 4 port t turn of volume', port vol A port volume • rrH(ST^ ml(5.TJ .^ A P° r e : 2 0 . 6 5 2 7 . 9 9 0 1 5 . 8 2 8 1 2 . 8 7 7 " 1 4 . 0 7 8 1 3 * 8 3 7 1 0 . 0 9 6 1 0 . 0 3 7 7 . 4 1 4 7 . 6 6 6 6 . 4 5 6 9 . 9 4 8 1 6 . 6 1 9 1 1 . 7 4 0 6 . 1 0 6 2 0 . 6 5 2 2 8 . 6 4 2 4 4 . 4 7 0 5 7 . 3 4 7 7 1 . 4 2 5 6 3 . 2 6 2 9 5 . 3 5 B 1 0 5 . 3 9 6 1 1 2 . 6 1 0 1 2 0 . 4 7 6 1 2 6 . 9 3 2 1 3 6 . 8 8 0 1 5 B . 4 9 8 1 6 5 . 2 3 9 1 7 1 . 3 4 5 0 . 1 2 & 4 0 5 0 . 3 6 6 6 3 1 0 . 5 1 7 3 0 9 0 . 7 1 4 3 0 8 1 . 0 2 0 8 2 2 1 . 3 9 0 0 8 6 1.640137> 2 . 1 2 6 0 * 1 , 2 . 4 1 7 4 8 0 2 . 9 2 6 7 1 3 4 . 7 7 8 1 7 2 2 5 . 9 8 2 2 6 5 2 6 . 0 9 8 5 5 7 6 . 7 3 3 9 5 7 2 . 6 0 1 6 5 2 0 . 9 2 6 0 . 8 7 3 . 0 . 8 3 3 0 . 7 9 9 0 . 7 2 4 0 . 6 5 4 0 . 5 9 9 0 . 5 4 3 0 . 4 6 7 0 . 4 2 3 0 . 3 8 5 0 . 3 6 9 0 . 3 6 2 0 . 3 5 5 0 . 3 4 8 0 . 3 2 6 0 . 2 9 1 . 0 . 2 4 8 0*6. 1 8 3 . 9 6 4 1 7 0 . 1 5 1 1 6 1 . 6 7 3 1 5 4 . 8 3 4 . 1 4 1 . 8 5 4 1 3 2 . 2 6 1 125.743 1 1 6 . 7 4 2 1 1 1 . 8 2 6 1 0 4 . 2 9 5 9 9 . 1 6 7 9 3 . 5 3 8 88.651 8 0 . 3 7 8 7 2 . 2 9 9 6 3 . 4 6 3 5 B . 0 7 9 . 5 3 . 1 6 9 wall separation .* 2 5 0 . 6 2 7 1 4 5 . 0 3 0 9 4 . 5 4 2 7 5 . 3 0 6 5 9 . 5 9 5 4 5 . 6 7 4 3 7 . 9 5 4 3 2 . 9 7 2 2 8 . 9 7 9 2 3 . 3 7 5 2 3 . 0 8 9 2 1 . 8 9 9 2 1 . 4 2 4 2 1 . 1 3 9 2 0 . 8 5 6 2 0 . 3 0 3 1 9 . 2 6 3 1 7 . 9 0 3 _ pore area — 1 . 0 9 2 3 . 1 3 5 2 . 894 2 . 9 3 0 7 . 0 4 0 6 . 666 5 . 2 8 4 6 . 4 5 6 7 . 1 8 7 8^747 6 . 5 2 5 8 . 0 2 7 0 . 2 6 4 1 1 . 6 5 6 1 2 . 4 4 4 13'. 348 7 . 5 3 2 6 . 3 5 7 sum of pore area sq-nyg. — 1 . 0 9 2 4 . 2 2 7 7 . 1 2 1 1 0 . 0 5 1 1 7 . 0 9 1 2 3 . 7 5 6 — 2 9 . 0 4 0 3 5 . 4 9 6 4 2 . 6 8 3 5 1 . 4 3 0 5 7 . 9 5 6 6 5 . 9 8 3 7 4 . 1 8 9 8 5 . 8 4 5 9 8 . 2 6 8 1 1 1 . 6 3 7 1 1 9 . 1 6 9 1 2 5 . 5 2 6 pore volume mLfST.r^ 9. " 8 ; 8 2 6 1 4 . 6 6 6 8 . 8 2 6 T . 118 1 3 . 5 3 4 9 . 8 2 1 — 6 . 4 7 0 6 . 8 6 6 6 . 7 1 9 7 . 2 1 7 7 . 9 4 B 8 . 3 7 2 8 . 7 4 2 4 . 6 8 0 3 . 6 7 2 sum of pore vol £ pore volume 8 . 8 2 6 2 3 . 4 9 2 3 2 . 3 1 8 3 9 . 4 3 6 5 2 . 9 7 0 6 2 . 7 9 1 6 9 . 2 6 1 7 6 . 1 2 8 8 2 . 8 4 6 9 0 . 0 6 3 9 4 . 9 2 3 1 0 0 . 5 9 4 1 0 6 . 2 6 5 1 1 4 . 2 1 3 1 2 2 . 5 8 4 1 3 1 . 3 2 7 1 3 6 . 0 0 7 1 3 9 . 6 7 9 0 . 0 6 5 2 T B 0 . 1 9 3 0 0 9 0 . 3 5 3 2 1 1 0 . 5 2 7 8 9 9 0 . 7 5 4 4 5 2 0 . 9 9 1 8 2 4 1 . 1 7 0 3 4 5 1 . 5 4 4 0 2 2 1 . 8 9 9 1 6 2 2 . 2 0 6 6 7 6 2 . 6 5 5 7 0 2 6 . 3 5 3 7 4 7 2 0 . 9 2 4 5 7 6 2 6 . 6 7 5 3 4 8 3 1 . 4 2 1 7 2 2 1 0 . 4 2 0 9 3 1 3 , 7 6 7 0 0 6 2 . 4 9 3 9 2 8 PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION PULP BEATEN 8 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION • 0 . 8 4 7 . . 0 . 0 3 8 0 . 7 7 3 0 . 7 1 0 0 . 6 5 2 0 . 6 0 8 0 . 5 4 8 , 0 . 4 9 5 J U + 5 5 0 . 4 0 7 0 . 3 7 0 0 . 3 6 1 0.354— 0 . 3 4 5 0 . 2 8 4 0 . 2 3 9 T597T29" 152.376 138.320 127.261 118.573 111.834' 104.210 98.338 93.523 67.931 6 3 . 4 4 2 76.419 Tl .174 66.170 584988 51.942 49.693 9 3 . 7 2 2 _ 7 2 . 9 1 6 9 4 . 7 0 7 4 4 . 4 1 1 3 8 . 2 7 7 S 3 . 5 1 2 2 9 . 4 1 3 _ 2 6 . 6 0 5 2 4 . 3 6 3 2 2 . 4 1 0 2 1 . 4 2 4 2 1 . 1 1 3 2 0 . 7 9 3 2 0 . 1 7 8 _ 1 9 . 0 7 3 1 7 . 6 3 6 "3.704 -2.656 6. 538 6.604 6.502 5.739 7.159 6i 173 5.559 "" f i O l * 5.920 7.782 3.704 6 . 3 6 0 _ 1 2 . 6 9 8 1 9 . 7 0 3 2 6 . 2 0 5 . 9 4 4 111 526 7. 894 J1.258 10.933 1.477 3 9 . 1 0 3 454 276 5 0 . 8 3 3 ' 3 7 . 8 4 9 " 6 3 . 7 6 9 7 1 . 5 3 1 U.STT 8 . 0 3 0 1 3 . 3 7 9 1 2 . 0 0 8 9 . 3 1 5 7 * 0 6 6 8 3 . 0 7 7 9 0 . 9 7 1 1 0 2 . 2 2 9 1 1 3 . 1 6 3 " 1 1 4 . 6 4 0 7 .75 f t 3 . 8 * 7 4 . 7 7 1 " 5 . 5 1 2 4 . 2 6 0 5 . 3 7 8 16.577 2 4 . 6 0 7 3 9 . 9 6 6 5 1 . 9 9 3 6 1 . 3 0 8 6 6 . 3 9 4 0 . 2 3 0 1 4 6 7 6 . 1 3 0 6 2 . 0 0 7 8 6 . 7 7 8 9 2 . 2 9 0 9 6 . 5 7 0 1 0 1 . 9 4 8 0 . 6 5 0 9 3 3 ; 0 . 9 3 6 6 8 9 1 . 1 9 4 1 0 0 1 . 5 6 6 3 9 0 7 . 8 5 0 5 . 295 7 . 3 2 8 ' 6 . 7 2 6 " 0 . 8 4 0 1 0 9 . 7 9 8 1 1 5 . 0 9 3 1 2 2 . 4 2 0 1 2 9 . 1 4 6 1 2 9 . 9 6 8 I T 575423 1 . 7 1 4 7 2 7 2 . 1 6 8 1 9 0 2 . 4 1 4 1 2 1 2 . 6 3 8 8 6 5 1 5 . 3 2 * 7 3 3 Z S . 6 8 1 9 9 8 1 4 . 3 9 3 5 * 4 8 . 4 9 9 5 7 6 5 . 0 0 7 7 0 2 0 . 5 4 9 0 1 * O ; B T 3 o . B i a 0 . 7 4 6 0 . 6 8 0 0 . 5 5 5 0 . 4 7 2 0 . 3 9 8 0 . 3 6 0 0 . 3 4 9 0 . 3 3 9 0 . 3 0 8 0 . 2 7 2 0 . 2 2 6 12*9; 9 20 1 2 1 . 8 9 1 1 1 2 . 3 5 9 1 0 5 . 0 9 0 9 4 . 2 2 7 8 8 . 3 2 1 8 2 . 6 7 6 7 6 . 8 7 8 6 7 . 3 1 7 6 0 . 6 3 4 5 4 . 0 9 1 3 0 . 1 9 9 4 6 . 9 * 4 1 3 9 . 2 9 8 ' 9 1 . 4 5 4 6 5 . 2 4 7 4 9 . 4 9 0 3 7 . 6 4 6 2 9 . 0 2 9 " 2 4 . 6 0 2 ' 2 2 . 0 0 7 2 0 . 9 9 0 2 0 . 5 7 0 1 9 . 7 9 6 1 8 . 6 0 6 1 7 . 2 4 7 1 . 9 1 9 3 . 0 0 3 4 . 9 4 9 4 . 9 5 1 9 ^ 3 5 7 6 . 3 0 7 7 . 067 8 . 4 0 3 1 5 . 0 6 4 1 1 . 1 8 6 10*. 318 5 . 8 4 B 5 . 9 6 6 1 .919 4 . 9 2 4 9 . 6 7 3 1 4 . 8 2 4 2 4 . 1 6 1 3 0 . 4 6 8 3 7 . 5 5 5 4 5 . 9 5 8 6 1 . 0 2 2 7 2 . 2 0 8 8 2 . 5 2 6 8 6 . 3 7 4 8 . 6 l 5 ~ 8 . 8 6 4 1 0 . 4 1 6 7 . 9 0 4 1 1 . 4 2 3 5 . 9 0 6 5 . 6 0 9 5 . 9 6 5 1 0 . 2 0 0 7 . 4 2 2 6 . 5 8 9 3 . 5 1 0 8 . ^ 2 ? 0 . 1 3 5 0 4 7 278568 3 0 5 7 7 2 723700 9 2 3 6 5 6 120676 1 7 . 4 8 9 2 7 . 9 0 5 3 5 . 8 0 9 4 7 . 2 3 2 5 3 . 1 3 8 5 8 . 7 4 7 — T 6 4 . 7 1 2 3 7 4 . 9 1 2 23, 8 2 . 3 3 4 18. 8 8 . 9 2 3 9 2 . 4 3 3 5*461f l .716944 7 2 1 1 0 0 0 7 8 7 2 0 794353 824673 9 2 . 3 3 4 2 . 2 0 3 9 4 . 6 3 6 — 1 . 4 9 2 4 7 8 P U L P BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION T J . 6 7 3 1 4 1 . 2 4 0 1 7 7 . 2 1 2 3 . 3 6 5 3 . 3 6 5 1 4 . 2 3 4 1 4 . 2 3 4 6 . 1 3 7 9 0 1 0 . 6 3 1 1 3 1 . 9 6 4 9 4 . 4 0 9 3 . 3 6 6 6 . 7 5 1 • 1 0 . 3 1 1 2 9 . 5 5 0 0 . 3 9 4 9 8 6 L 0 . 7 7 4 _ . 1 2 1 . 6 7 2 _ 7 1 . 3 1 2 4 . .S54 1 1 . 3 0 6 1 0 . 4 7 6 4 0 . 0 2 6 0 . 5 2 1 7 4 7 0 . 7 2 9 1 1 3 . 8 9 4 5 6 . 3 6 1 4 . 3 3 1 1 5 . 8 3 6 8 . 2 4 0 4 8 . 2 6 7 0 . 8 4 2 2 4 1 0 . 6 6 6 1 0 5 . 0 9 2 4 6 . 8 4 3 6 . 0 9 3 2 1 . 9 3 0 9 . 2 0 8 5 7 . 4 7 4 0 . 9 9 0 9 6 0 0 . 6 0 9 9 8 . 2 3 3 3 » - ' 3 ? 5 . 5 0 4 2 7 . 4 3 4 6 . 9 4 4 6 4 . 4 2 3 1 . 1 3 3 9 8 4 0 . 3 6 2 9 3 . 0 7 6 3 4 . 1 0 1 : 4 . 6 5 7 5 5 7 0 9 1 5 . 1 2 3 6 9 . 5 4 5 — 1 . 3 0 1 3 4 3 0 . 5 0 5 . 8 6 . 9 5 5 3 0 . 2 2 0 . 6 . 1 7 7 3 8 . 2 6 6 6 * 0 2 2 7 5 . 5 6 7 1 . 5 7 3 9 8 5 0*45,5 8 2 t 3 4 6 2 6 . 8 9 5 5 . 0 4 0 _ 4 3 . 3 0 8 4 . 3 7 2 7 9 . 9 3 9 1 . 3 4 8 0 6 5 0 . 4 1 8 7 8 . 5 4 4 ' 2 4 . 6 0 0 4 . 6 2 2 4 7 . 9 3 0 3 . 6 6 8 1 8 3 . 6 0 7 2 . 0 7 7 6 5 9 0 . 3 7 4 7 4 . 1 2 * 2 2 . 7 5 6 5 . 6 1 4 5 3 . 5 4 4 4 . 1 2 1 8 7 . 7 2 8 2 . 1 4 3 7 9 1 0 . 3 * 1 6 9 . 3 1 8 2 1 . 3 1 2 7 . 1 2 0 6 0 . 6 * 3 4 . 9 4 1 9 2 . 6 6 9 8 . 7 1 3 8 5 2 0 . 3 5 2 6 4 . 8 3 4 2 1 . 0 * 6 67TC3 6 7 . 5 1 2 4 . 6 4 9 9 7 . 3 1 8 1 2 . 7 2 * 1 7 2 P . 3 * 0 5 8 . 4 1 4 2 0 . 6 3 5 1 0 . 0 0 9 7 7 . 5 2 1 6 . 6 6 3 1 0 3 . 9 8 1 1 4 . 6 4 6 8 2 6 • 0 . 3 1 1 5 3 . 0 3 7 1 9 . 8 7 6 . 8 . 0 4 0 6 5 . 9 6 1 _ _ 3 . 1 3 S 1 0 4 . 1 3 6 4 . 8 4 2 1 9 4 0 , 2 7 0 4 6 . 1 5 3 1 6 . 6 3 7 7 . W 6 . 9 2 . 7 * 7 "~ 4 . 3 2 6 1 1 3 . 4 * 2 3 . 0 6 0 3 4 1 'UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE DRYING UNBEATEN PULP SHEETS WITH 5.3% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING ""0;«&T 0 . 6 * 2 0 . 7 T 0 0 . 7 1 0 0 . 6 7 3 , 0 . 5 9 9 6.53Y 0 . 4 7 9 0 . 4 3 5 0 . 4 1 9 0 . 3 9 0 0 . 3 6 4 6.355 0 . 3 4 7 0 . 3 3 * OH, 311 0 . 2 6 5 " 3 7 5 7 6 3 . 4 7 6 3 . 3 8 0 _ 3 . 2 9 9 3 . 2 6 3 3 . 1 5 0 3 . 6 7 3 2 . 9 7 7 2 . 6 8 5 _ 2 . 8 6 3 2 . 7 8 7 2 . 6 * 6 2 . 4 4 6 2 . 2 2 6 2 .044„ 1 . 6 0 6 1 . 5 6 5 1 9 0 J 6 O 3 . 1 1 2 . 0 2 7 7 3 . 5 5 7 5 4 . 3 3 3 4 5 . 6 8 2 3 9 . 1 5 4 32.747 2 8 . 5 9 1 2 5 . 6 5 9 2 4 . 0 4 0 2 3 . 0 3 5 2 1 . 9 1 5 2 1 . 1 8 V 2 0 . 6 4 6 2 0 . 4 8 0 1 9 . 7 9 9 1 8 . 9 5 0 0 . 0 1 6 0 . 0 3 0 _ 0 . 0 4 3 0 . 6 * 9 . 0* .025-0~.094 0 . 0 7 3 0'. 106 0 . 1 1 3 0 . 0 2 7 6 . 104 0 . 1 7 6 0 . 3 * 3 0 . 3 4 7 0 . 3 B 5 0 . 3 9 1 ~ 0 " : 0 1 6 " " 0 . 0 4 5 0.0a a_ 0 . 1 3 7 -0.163 0 . 2 5 6 0 . 3 3 0 0 . 4 3 5 0 . 5 4 9 0 . 5 7 5 " 0 . 6 6 0 0 . 8 5 6 1.140 1 . 5 4 6 1 . 8 2 6 2 . 2 1 1 2 . 6 0 2 0 . 6 4 6 0 . 1 0 7 0 . 1 0 2 • 0 . 0 8 6 0 . 0 3 7 0 . 1 1 8 O . 0 7 8 0 . 0 9 8 0 . 0 9 4 0 . 0 2 1 0 . 0 7 7 0 . 1 2 5 0 . 2 3 4 0 . 2 3 4 0 . 1 8 5 0 . 2 4 6 0 . 2 3 4 0 . 6 4 * 0 . 2 0 3 -„0 .305 0 . 3 9 1 0 . 4 2 8 0 . 5 4 7 0 . 6 2 * 0 . 7 2 2 0 . 8 1 5 0 . 8 3 6 0 . 9 1 4 1 . 0 3 8 1 . 2 7 2 1 . 3 0 6 1 . 6 9 1 1 . 4 3 7 2 . 1 7 1 0 . 0 0 0 9 0 2 0 . 0 0 2 1 1 2 0^003877 0 . 0 0 7 0 8 5 0 . 0 0 7 2 3 8 0 . 0 1 4 9 6 4 0 . 0 1 6 1 0 6 0 . 0 2 7 1 8 6 0 . 0 4 1 1 7 9 0 . 0 2 2 4 8 6 0 . 0 6 8 7 8 1 0 . 1 1 1 9 2 0 0 . 6 6 0 3 2 4 0 . 7 5 1 1 2 7 0 . 4 3 5 7 0 1 0 . 2 5 9 9 2 1 0 . 1 5 1 4 9 2 0 . 8 6 3 ' 5 . 3 9 4 1 4 4 . 1 1 2 6 . 6 4 3 0 . 0 4 3 0 . 2 0 1 6 . 2 0 1 0 . 0 0 2 2 * 6 0 . 7 8 9 5 . 2 7 4 8 2 . 3 9 0 0 . 0 4 9 0 . 0 9 2 0 . 130 0 . 3 3 0 0 . 0 0 3 8 2 6 0 . 7 1 8 5 . 1 6 5 5 7 . 3 4 9 0 . 064 0 . 1 5 6 0 . 1 1 8 0 . 4 4 B 0 . 0 0 7 4 9 7 0 . 6 4 6 5 . 0 3 4 4 4 . 7 4 9 6 . 0 9 8 0 . 2 5 3 0 . 1 4 1 0 . 5 9 0 0 . 0 1 4 3 4 9 0 . 5 8 3 4 . 9 2 9 3 6 . 8 1 0 ' 0 . 0 9 3 0 . 3 4 6 0 . 1 1 O 0 . 7 0 0 0 . 0 1 8 2 4 7 0 . 5 2 4 4 . 801 3 1 . 6 5 9 0 . 1 3 2 0 ; 4 7 6 0 . 1 3 4 0 . 8 3 4 0 . 0 3 1 4 9 3 0 . 4 8 3 4 . 6 9 3 2 8 . 2 6 0 0 . 1 2 4 0 .6O1 0 . 1 1 3 0 . 9 4 7 0 . 0 4 4 4 6 1 0 . 4 4 7 4 . 594 2 6 . 0 4 8 0". 122 0 . 7 2 3 0 . 1 0 3 1 . 0 4 9 0 . 0 5 4 2 0 2 0 . 4 1 1 4 . 4 7 8 2 4 . 2 4 5 0 . 154 0 . 8 7 7 0 . 1 2 0 1 . 170 0 . 0 7 0 1 2 2 0 . 3 8 7 4 . 3 9 2 2 2 . 8 5 4 0 . 119 0 . 9 9 6 0 . 0 8 8 . 1 . 2 5 8 0 . 0 8 2 5 5 9 0 . 3 6 1 4 . 0 9 0 2 1 . 7 8 7 0 . 4 6 0 1 . 4 5 6 0 . 3 2 3 1 . 5 8 1 0 . 3 0 2 5 5 0 0 . 3 4 5 3 . 5 5 7 2 0 . 9 3 8 0 . 8 5 4 2 . 3 1 1 0 . 5 7 7 2 . 1 5 6 0 . 9 1 6 1 1 4 0 . 3 3 6 3 . 1 6 6 2 6 . 4 4 5 6 . 6 4 0 2 . 4 5 1 6 . 4 2 2 2 . 5 8 0 1 . 1 8 6 5 9 9 0 . 3 2 1 2 . 8 4 5 1 9 . 9 8 0 0 . 5 2 5 3 . 4 7 6 0 . 3 3 8 2 . 9 1 8 0 . 5 6 8 8 1 9 0 . 2 9 0 2 . 5 5 1 1 9 . 1 4 6 0 . 4 7 5 3 . 9 5 0 0 . 2 9 3 3 . 2 1 2 0 . 2 6 7 9 9 3 -232-APPENDIX D Table 5: Pore Volumes Expressed as Bulk L i q u i d Volumes Unbeaten Pulp Solvent Exchange Dried from Water Suspension Nitrogen A n a l y s i s Argon A n a l y s i s Pore Pore Cumulative Pore Pore Cumulative Size Volume Volume Size Volume Volume a ml.xlO 3 ml.xlO 3 a ml.xlO 3 ml.xlO 3 96.5 36.4 .36.4 113.5 30.1 30.1 69.8 32.4 68.8 80.0 24.5 54.6 55.2 27-7 96.5 62. 3 20.9 75.5 45-7 19-1 115.6 51.2 17.3 92.8 39-1 16.7 132.3 43.6 15. 4 108.2 34.1 13.0 145.3 37.8 13-3 121.5 30.2 10.5 155-8 33.3 11.3 132.8 27-1 14.1 169-9 29.6 13.0 145.8 25.2 28.2 198.1 26.6 12.8 158.6 24.2 15.4 213-5 24.1 12.7 171.3 23-3 7.1 220.6 22.5 6.3 177.6 22.0 7.3 227-9 21.8 6.7 184.3 20.2 6.7 234.6 21.4 26.1 210.4 21.0 13.6 224.0 20.6 6.5 230.5 • 20.2 4.7 235.2 19.5 8.7 243.9 18.1 7.2 251.1 -233-Table 5 Continued Unbeaten Vacuum-Dried-Solvent Exchange Dried Handsheet Nitrogen A n a l y s i s _ Argon A n a l y s i s Pore Pore Cumulative Pore Pore Cumulative Size Volume Volume Size Volume Volume a ml.xlO 3 ml.xlO 3 a ml.xlO 3 ml.xlO 3 96.5 0.277 0.277 113.5 0.097 0.097 69.8 0.190 0.467 80.0 0.111 0.209 55.2 0.146 0.614 62.3 0.097 O.305 45-7 0.086 0.697 51.2 0.082 0.387 39.1 0.055 0.754 43.5 0.081 0.468 34.1 0.056 0.809 37.8 0.095 0.563 30.2 0.084 0.893 33-3 0.092 0.655 27-1 0.198 1.091 29.6 0.106 0.760 25.2 0.299 1.388 26.6 0.118 O.878 24.2 0.466 1.854 24.1 0.130 1.008 23.3 0.270 2.124 22. 5 0.079 1.087 22.0 0.115 2.240 21.8 0 .066 1,155 20.2 0.377 2.617 21.4 0.178 1.331 21.0 0.386 1,717 20.6 0.301 2.018 20.2 0.160 2.178 19.5 0.269 2.448 18.1 0.289 2.735 -234-APPENDIX D Table 6: Reduced Cumulative Pore Volumes* Parameter: Minutes Beaten. Wall Unbeaten Separation Beaten 1 Minute Beaten 3 Minutes Beaten 5 Minutes Beaten 10 Minutes 96.8 0.155 0.223 0.252 0.261 0.250 70.3 0.294 0.343 0. 410 0.412 0.394 55.6 0.412 0. 440 0.517 0.514 0.503 46.2 0.493 0.513 0.596 0.582 0.590 39.5 0.564 0.567 0.658 0.639 0.643 34.5 0.619 0.611 0.707 O.678 O.696 30.6 0.664 0.655 0. 746 0.712 0.733 27.4 0. 724 0.717 0.786 0. 740 0.775 25-5 0.845 0.828 0.828 0.759 0.818 24.5 0.910 0.911 0.920 O.885 O.918 23.6 0.941 0.940 0.947 0.923 0.943 22.3 0.972 0.972 0.982 0.971 0.973 20.5 1.000 1. 000 1.000 1.000 1.000 * C a l c u l a t e d from normalized n i t r o g e n desorption isotherms assuming the p a r a l l e l sided f i s s u r e model. The pore volumes are expressed as r a t i o s . -235-Table 6 C o n t i n u e d : Parameter: M o i s t u r e Content D r y i n g , W a l l Vacuum S e p a r a t i o n D r i e d 5-3 % 96.8 0.106 0.078 70.3 0.178 0.124 55.6 0.234 0.153 46.2 0.267 0.181 39.5 0.288 0.207 34.5 0.309 0.239 30.6 0. 341 0.272 27. 4 0.416 0.. 398 25.5 0.531 0.546 • 24.5 0. 709 0.682 23.6 0.811 0. 817 22. 3 0. 855 0.925 20.5 1.000 1.000 P r i o r t o S o l v e n t Exchange 14.4 % 33.6 % S a t u r a t e d 0.038 0.073 0.155 0.061 0.156 0.294 0.082 0.243 0.412 0.106 0.330 0.493 0.130 0.405 0.564 0.153 0.472 0.619 0.179 0.530 0.664 0.293 0.624 0. 724 0. 429 0.769 0.845' 0.700 0.846 0.910 0.789 0.921 0.941 0.903 0.966 0.972 1. 000 1.000 1. 000 Table 6 C o n t i n u e d : -236-Parameter: V a r i o u s C e l l u l o s i c M a t e r i a l s S o l v e n t Exchange D r i e d W a l l Regenerated S e p a r a t i o n C e l l u l o s e Wood C o t t o n a (172) (13) (18) 9 6 . 8 0.123 O.I89 0.094 70.3 0.223 0.334 0.157 55.6 0.312 0.427 0.200 46.2 0.389 0.489 0.242 39-5 0.447 0.549 0.284 34.5 • 0.522 0.625 0.306 30.6 0.605 0.703 0.319 27-4 0.723 0.781 0.387 25-5 0.808 0.810 0.476 24.5 0.893 0.853 0.652 23-6 0.960 0.922 0.782 22. 3 O.989 0.967 0.904 20.5 1.000 1.000 1.000 - 2 3 . 7 -APPENDIX E Grades and S u p p l i e r s of Chemical Used. Chemical Grade Continuous Flow Apparatus: He - N 2 Mixtures N 2 (gas) He C e r t i f i e d Standard Te c h n i c a l Technical S u p p l i e r Matheson of Canada Canadian L i q u i d A i r Canadian L i q u i d A i r Volumetric Apparatus N 2 (gas) Ar ° 2 He ' Research Research Research Research Matheson of Canada Matheson of Canada Matheson of Canada Matheson of Canada Solvent E x t r a c t i o n : Methanol n-Pentane Sodium Metal Absolute S p e c t r a l Reaction F i s h e r S c i e n t i f i c Co, F i s h e r S c i e n t i f i c Co, Magnesium Turnings Reaction F i s h e r S c i e n t i f i c Co, L i q u i d Nitrogen Commercial Canadian L i q u i d A i r -238-APPENDIX F Table 1: Argon Adsorption on Nonporous Adsorbent. (Zinc C r y s t a l s ) From Rhodin (165) p/p 0 Volume Adsorbed* v/v m 0.05 0.300 0.611 0.10 0. 420 0.856 0.15 0.505 1.029 0.20 • 0.570 1.161 0.25 0.608 1.239 0.30' 0.632 1.288 0.35 O.656 1.336 0.40 0.682 1.389 0. 45 0.705 1.436 0.50 0.731 1.489 0.55 0.758 1.544 0.60 0.789 1.607 0.65 0.820 1.671 0.70 0.850 1.732 0.75 0.880 1.793 0.80 0.923 1.880 0.85 1.000 2.037 0.90 1.185 2.414 0.95 1.455 2.964 * Expressed as micrograms/gram -239-APPENDIX P Table 2: Nit r o g e n "Standard" Isotherms Standard Isotherm of Payne and Sing (171) P/P G v/v m " t " P/P 0 v/v m " t " 0.005 0.632 0.30 1. 34 4.78 0.01 0.730 0.32 1.38 4.89 0. 02 0. 817 0.34 1.41 5.00 0.03 0.866 0.36 1.45 5.16 0.04 0. 895 0.38 1.48 5.26 0.05 0.924 0. 40 1.52 5.37 0.06 0.953 0.42 1.55 5.48 0.07 0.982 3-49 0.44 1.575 5.59 0.08 1.002 3.55 0.46 1. 60 5,69 0.09 1.022 3.63 0.48 1.63 5-80 0.10 1.042 3.71 0.50 1.66 5.91 0.12 1.07 3.81 0.55 1.77 6.29 0.14 1.11 3.92 0.60 1.88 6.66 0.16 1.14 4.03 0.65 2.01 7,14 0.18 1.17 4.14 0. 70 2.16 7,68 0.20 1.20 4.24 0.75 2.32 8,27 0.22 1.225 4.35 0.80 2.60 9.24 0.24 1.255 4.46 0.85 2.95 10.48 0.26 1.28 4.57 0.90 3-55 12.6 0.28 1.31 4.67 0.95 5.64 20, -240-T a b l e 2 C o n t i n u e d : S t a n d a r d I s o t h e r m o f L i p p e n s , L i n s e n and de Boer (110) P/P G m " t " P/Po • m " t " 0.08 0.99 3.51 0.54. 1.93 6.82 0.10 1.04 3.68 0.56 1.97 6.99 0.12 1.08 3.83 0.58 2.03 7.17 0.14 1.12 3-97 0.60 2.08 7-36 0.16 1.16 4.10 0.62 2.14 7.56 0.18 1.19 4.23 0.64 2.19 7.77 0.20 1.23 4.36 0.66 . 2.27 8.02 0.22 1.27 4.49 0.68 2.33 8.26 0.24 , 1-31 4.62 0.70 2.42 8,57 0.26 1.34 4.75 0.72 2.52 8.91 0.28 1.38 4.88 0.74 2.61 9.27 0.30 1.42 5.01 0.76 2.73 9.65 0.32 1.45 5.14 0.78 2.84 10.07 0.34 1.49 5.27 0.80 2.99 10.57 0.36 1.53 5.41 0.82 3.16 11.17 0.38 . 1.57 5-56 0.84 3.36 11. 89 0.40 \ 1.61 5-71 0.86 3.60 12.75 0.42 . 1.66 5.86 0.88 3.90 13.82 0.44 1.70 6.02 0.90 4.22 14.94 0.46 1.75 .6.18 0.92 , 4.52* 16.0* 0.48 1.79 '6.34 0.94 4.94* 17.5* 0.50 1.84 6.50 0.96 5.59* 19.8* 0.52 1.88 6.66 0.98 6.47* 22.9* * E x t r a p o l a t e d Data g i v e n by L i p p e n s , L i n s e n and de Boer -241-Table 2 C o n t i n u e d : S t a n d a r d I s o t h e r m from P i e r c e (48) C a l c u l a t e d u s i n g the f o l l o w i n g e q u a t i o n : l o g 1 ( J ( p 0 / p ) P/P G m " t " P/P 0 v/v m " t " 0.20 1.27 4.51 0.46 1.66 5.88 0.22 1.30 4.61 0.48 1.70 6.00 0.24 1.33 4.71 0.50 1.73 6.13 0.26 1.36 4.81 0.55 • 1.83 6.47 0.28 1.39 4.91 0.60 1.93 6.85 0.30 1.42 5.01 0.65 2.06 7.28 0.32 1.44 5.12 0.70 2.20 7.80 0.34 1.47 5.22 0.75 2.38 8.44 0.36 1.50 5-32 0.80 2.61 9.25 0.38 1.53 5.43 0.85 2.93 10.38 0.40 1.56 5-54 0.90 3.43 12.16 0.42 1.60 5.65 0.95 4.46 15- 80 0.44 ' 1.63 . 5.76 -242-APPENDIX G TABLE!: CORRECTED DUBININ DATA PARALLEL SIDED FISSURE MODEL > C < £ l " V i a . UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0 . 0 0 4 2 3 1 4 . 2 5 2 5 . 3 5 1 5 . 6 3 4 2 6 0 . 7 2 8 4 3 0 . 0 2 6 6 9 3 0 . 7 1 0 1 7 . 3 6 9 2 . 4 7 6 38 1 . 2 3 9 7 8 0 . 0 3 5 6 0 3 3 . 5 1 4 1 9 . 6 9 6 2 . 0 9 8 2 9 1 . 2 9 4 3 8 0 . 0 7 0 9 0 3 9 . 0 4 7 2 3 . 6 6 5 1 . 3 2 1 0 1 1 . 3 7 4 1 0 0 . 0 9 3 3 0 4 1 . 6 6 4 2 5 . 6 0 7 1 . 0 6 1 1 4 1.40 636 0 . 1 1 8 7 0 4 4 . 4 1 1 2 7 . 7 1 8 0 . 8 5664 1 .442 76 0 . 1 6 2 1 0 48.3'2'7 . 3 0 . 4 9 9 0 . 6 2 4 4 4 1 .4B429 0 . 2 1 5 5 0 5 3 . 3 2 7 3 4 . 2 8 2 0 . 4 4 4 2 9 1 .53506 0 , 2 7 7 7 0 5 B . 5 7 9 3 8 . 116 0 . 3 0 9 6 1 1 .58111 0 . 3 2 7 5 0 6 3 . 6 3 5 4 1 . 8 6 7 0 . 2 3 5 0 2 1. '62187 0 . 3 8 7 B O 6 9 . 6 9 2 4 6 . 3 7 4 0 . 1 6 9 2 4 1 . 6 6 6 2 8 0 . 4 7 3 6 0 7 9 . 5 7 0 5 4 . 1 8 6 0 . 1 0 5 3 6 1 .733B8 0 . 5 3 2 2 0 B 6 . B 4 1 5 9 . 8 6 5 0 . 0 7 5 0 3 1 . 7 7 7 1 7 0 . 6 2 5 7 0 101 . 7 2 9 7 1 . 3 6 3 0 . 0 4 1 4 7 1 . 8 5 3 4 7 0 . 7 0 1 8 0 1 1 8 . 5 0 5 8 4 . 6 8 1 0 . 0 2 3 6 5 1 ,9277b 0 . 7 7 3 3 0 1 3 6 . 7 1 0 9 8 . 6 1 5 0 . 0 1 2 4 7 1 . 9 9 3 9 4 0 . 8 1 7 1 0 1 5 0 . 6 4 5 1 0 8 . 3 3 6 0 . 0 0 7 7 0 Z . 03477 0 . 8 9 7 9 0 1 8 7 . 5 8 9 1 3 2 . 5 9 7 0 . 0 0 2 1 9 2 . 1 2 2 53 PULP BEATEN I MINUTE —rSOLVENT EXCHANGE ORIEO FROM WATER SUSPENSION • 0 . 0 0 1 0 6 8 . 9 8 8 6 . 2 6 1 6 . 8 4 6 8 1 0 . 7 9 6 6 7 0 . 0 0 3 5 0 1 5 . 6 * 5 8 . 0 9 2 6 . 0 3 4 0 4 0 . 9 0 B 0 8 0 . 0 1 9 1 4 2 7 . 7 2 0 1 5 . 2 8 4 2 . 9 5 1 4 1 1 . 1 6 4 2 5 0 . 0 5 0 3 8 3 4 . 6 1 7 2 0 . 5 0 3 1 . 6 8 4 1 8 1 .31181 0 . 0 7 B 4 9 3 B . 4 3 0 2 3 . 1B1 1 . 2 2 1 4 3 1 . 3 6 5 1 2 0 . 1 2 B 5 7 4 3 . 2 2 6 2 6 . 6 6 6 0 . 7 9 3 6 0 1 . 4 2 5 9 6 . 0 . 1 7 ) 6 8 4 7 . 0 5 8 2 9 . 4 3 6 0 . 5 8 5 6 5 1 . 4 6 8 8 7 0 . 2 2 2 1 6 5 i . 1 0 7 3 2 . 3 6 1 0 . 4 2 6 8 6 1 . 5 1 0 0 2 0 . 2 8 1 7 7 0 . 3 4 2 6 0 0 . 4 0 0 5 1 0 . 4 6 4 8 0 0 . 5 2 8 6 7 0 . 6 2 5 7 6 . 0 . 7 0 3 2 7 0 . 7 7 7 7 9 0 . 8 3 6 5 0 5 5 . 9 7 0 61 . 5 3 3 6 7 . 2 1 9 7 4 . 1 9 1 81 . 031 9 4 . 5 3 2 1 1 0 . 7 8 5 1 2 8 . 2 1 2 1 4 4 . 7 6 8 3 5 . 8 9 7 3 9 . 9 4 7 4 4 . 0 5 6 4 9 , 5 9 9 5 4 . 8 1 0 6 4 . 8 7 7 7 7 . 6 8 ' 9 0 . 6 3 7 1 0 1 . 3 6 4 0 . 3 0 2 6 1 0 . ^ 1 6 4 2 0 . 15791 0 . 11071 0 . 0 7 6 6 3 0 . 0 4 1 4 5 0 . 0 2 3 3 7 0 . 0 1 1 9 1 0 . 0 0 6 01 1 ,55506 1 . 6 0 1 4 8 1 . 6 4 4 0 0 1 . 6 9 5 4 7 1 . 7 3 8 8 6 1 . 8 1 2 0 9 1 . 8 9 0 3 4 1 . 9 5 7 3 1 2 . 0 0 5 8 8 £ J£* *r«<ft ^ UNBEATEN PULP — SOLVENT EXCHANGE DRIED FROM "WATER SUSPENSION 0 . 0 0 0 1 4 3 . 3 0 6 2 . 9 3 3 ; 1 4 . 8 5 2 3 2 0 . 4 6 7 2 9 0 . 0 0 0 8 2 B . 5 6 6 6 . 4 7 0 9 . 5 2 4 5 4 0 . 6 1 0 8 6 0 . 0 0 4 1 7 1 7 . 3 3 4 8 . 9 0 6 . 5 . 6 6 3 7 5 0 . 9 4 9 6 7 0 . 0 1 2 5 0 2 5 . 7 0 5 1 4 . 2 8 3 3 . 6 2 1 7 5 1 . 1 5 4 8 2 0 . 0 3 5 8 0 3 3 . 5 1 7 2 0 . 3 0 0 2 . 0 9 1 2 3 ..'-l.aQ74j_ , 0 . 0 5 3 3 0 3 7 . 1 3 7 - 2 3 . 1 9 2 1 . 6 2 1 2 2 1 . 3 6 5 3 4 . 0 . 0 8 4 2 0 4 0 . 4 8 3 . 2 5 . 6 9 8 1 . 1 5 4 9 5 . 1 . 4 1 3 2 7 0 . 1 3 1 5 0 4 5 . 8 3 9 2 9 . 5 4 3 0 . 7 7 6 2 9 1 . 4 7 0 4 5 0 . 1 7 4 9 0 4 9 . 6 2 7 3 2 . 3 0 6 0 . 5 7 3 3 7 1 . 5 0 9 2 6 0 . 2 1 3 0 0 5 3 . 2 4 5 3 5 . 0 9 3 0 . 4 5 1 0 7 1 . 5 4 5 2 2 0 . 2 5 2 3 0 5 6 . 5 7 7 3 7 . 5 6 9 . 0 . 3 5 7 7 0 ,. L . 5 7 4 8 3 _ 0 . 2 9 5 3 0 6 0 . 6 2 3 4 0 . 6 7 8 0 . 2 8 0 6 2 1 . 6 0 9 3 6 0 . 3 3 9 0 0 6 4 . 6 1 9 4 3 . 5 7 3 0 . 2 2 0 7 1 1 . 6 3 9 2 2 0 . 4 0 B 2 0 7 1 . 7 6 7 4 8 . 9 0 8 0 . 1 5 1 4 2 1 . 6 8 9 3 8 0 . 4 7 2 3 0 7 9 . 3 9 9 5 5 . 161 0 . 1 0 6 1 3 1 .741 II 0 . 5 3 8 7 0 • 6 8 . 1 1 8 6 2 . 1 0 3 0 . 0 7 2 1 7 1 . 7 9 3 1 1 0 . 6 0 0 4 0 9 7 . 7 2 1 6 9 . 6 6 9 0 . 6 6 9 8 0 1 1 0 . 8 4 0 7 9 . 9 2 3 0 . 0 3 0 3 0 1 . 9 0 2 6 7 0 , 7 3 8 6 0 1 2 7 . 3 0 0 9 3 . 1 6 9 0 . 0 1 7 3 2 1 . 9 6 9 2 7 • 0 . 7 8 9 4 0 1 4 1 . 1 9 0 1 0 3 . 3 9 8 0 . 0 1 0 3 5 2 . 0 1 4 5 1 0 . 9 3 3 8 0 1 5 5 . 3 4 0 1 1 3 . 1 4 4 0 . 0 0 6 2 3 2 . 0 5 3 6 3 0 . 8 6 1 2 0 1 7 6 . 8 9 0 1 2 7 . 6 9 6 0 . 0 0 3 0 2 / . 2 . 1 0 6 1 8 BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSK 0 . 0 0 0 4 6 6 . 3 0 7 ' 5 . 2 1 0 1 1 . 1 3 7 1 8 0 . 7 1 6 8 7 f l . 0 0 164 11 . 1 ? 0 7 . 2 2 8 7 . 7 5 7 1 0 0 . 8 5 9 0 1 0 . 0 1 5 8 0 2 4 . 3 4 5 - 1 2 . 6 8 8 3 . 2 4 5 1 3 1 . 1 0 3 4 0 0 . 0 2 0 9 5 2 6 . 2 3 3 1 4 . 2 0 0 2 . 8 1 8 2 8 1 . 15230 0 . 0 4 8 3 8 3 1 . 9 9 6 1 8 . 5 6 1 1 . 7 3 0 0 3 0 . 0 7 7 1 1 3 5 . 9 1 7 2 1 . 3 4 3 1 .23B57 1 . 3 2 9 2 6 0 . 1 3 7 7 2 4 1 . 0 3 9 2 4 . 9 0 6 - 0 . 7 4 1 3 5 1 . 3 9 6 3 1 0 . 1 8 8 3 4 4 5 . 1 0 4 2 7 . 8 6 6 0 . 5 2 5 7 0 1 . 4 4 5 1 1 0 . 2 4 9 1 4 4 9 . 9 1 0 3 1 . 3 7 8 0 . 3 6 4 2 9 1 . 4 9 6 6 3 0 . 3 1 6 2 7 5 4 . 7 9 7 3 4 . 6 6 7 0 . 2 4 7 2 1 . 1 . 5 3 9 9 1 0 . 3 9 0 8 6 61 . 3 1 0 3 9 . 4 1 2 0 . 1 6 6 4 5 0 . 4 6 2 1 8 6 8 . 2 6 6 4 4 . 7 6 5 0 . 11235 1 . 6 5 0 9 4 0 . 5 2 8 0 7 7 6 . 0 4 3 5 0 . 9 4 6 0 . 0 7 6 9 0 1 . 7 0 7 1 1 0 . 5 8 5 5 1 B 3 . 0 1 7 5 6 . 0 3 6 0 . 0 S 4 0 4 1 . 7 4 8 4 6 0 . 6 4 0 7 7 9 2 . 2 1 3 6 3 . I B S 0 . 0 3 7 3 6 1 . 8 0 0 6 3 0 . 7 0 1 9 9 1 0 4 . 0 0 2 7 2 . 3 5 4 0 . 0 2 3 6 1 1 . 8 5 9 4 6 0 . 7 5 4 3 4 1 1 5 . 6 7 3 8 1 . 4 1 6 0 . 0 1 4 9 9 1 . 9 1 0 7 1 0 . 8 0 4 5 3 1 2 8 . 9 5 2 9 0 . 5 8 2 0 . 0 0 8 9 2 1 . 9 5 7 0 4 0 . 8 4 3 5 3 1 4 2 . 4 2 1 1 0 0 . 0 7 7 0 . 0 0 5 4 6 2 . 0 0 0 3 3 . 0 . 8 6 6 3 9 1 5 3 . 1 8 0 1 0 7 . 6 2 8 0 . 0 0 3 8 8 2 . 0 3 1 9 3 PULP BEATEN S MINUTES—SOLVENT EXCHANGE ORIEO FROM WATER SUSPENSION PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE ORIEO FROM WATER SUSPENSION 0 . 0 0 0 3 2 6 . 4 9 3 5 . 8 9 3 1 2 . 2 1 3 9 8 0 . 7 7 0 3 4 0 . 0 0 2 8 5 1 5 . 3 8 2 1 0 . B S 8 • 6 . 4 7 7 B 1 1 . 0 3 5 7 3 0 . 0 1 1 9 4 2 3 . 4 * 3 1 5 . 4 4 5 3 . 6 9 7 9 1 1. 18879 0 . 0 1 3 9 9 ' 2 5 . 0 2 6 1 6 . 7 2 4 3 . 4 3 7 9 9 1 . 2 2 3 3 5 0 . 0 3 1 0 0 2 9 . 8 6 8 2 0 . 6 3 2 2 . 2 7 599 1 . 3 1 4 5 5 0 . 0 6 6 8 0 3 4 . 3 7 7 2 4 . 0 4 1 1 . 3 8 1 1 5 1 . 3 8 0 9 5 0 . 1 0 2 9 0 ' 3 8 . 0 3 7 2 6 . 9 2 8 0 . 9 7 5 3 2 1 .43021 0 . 1 5 1 9 0 41 . 0 8 4 2 9 , 1 0 9 0 . 6 6 985 ( . 4 6 4 0 ? 0 . 2 0 3 7 0 4 4 . 3 5 6 3 1 . 5 9 0 0 . 4 7 7 4 9 1 . 4 9 9 5 5 0 . 2 6 2 5 0 4 7 . 8 4 B 3 4 . 171 0 . 3 3 7 4 1 1 . 5 3 3 6 6 0 . 3 5 1 0 0 5 3 . 0 8 1 3 7 . 8 8 5 0 . 2 0 6 7 5 1 . 5 7 8 4 7 0 . 4 Z 5 2 0 5 8 . 5 3 9 4 2 . 0 3 1 0 . 1 3 7 9 4 1 . 6 2 3 5 7 0 . 4 9 6 3 0 6 4 . 2 9 4 4 6 . 6 8 4 0 . U 9 2 5 7 1 . 6 6 9 1 7 0 . 5 6 9 2 0 7 1 . 5 b 8 5 2 . 3 1 8 0 . U 5 9 9 0 1 . 7 1 8 6 5 0 . 6 7 6 2 0 0 . 7 5 6 6 0 0 . 8 5 6 9 0 1 2 2 . 6 2 . 4 4 3 7 3 . 1 1 0 9 0 . 1 6 2 • 0 . 0 2 8 8 7 0 . 0 1 4 6 7 0 . 0 0 4 5 0 1 , 7 9 6 9 5 1 . 8 6 3 9 8 1 . 9 5 5 0 2 0 . 0 0 1 1 7 a . M l 5 . 9 9 6 6 . 5 9 5 5 3 0 . 7 7 7 9 8 0 , 0 0 3 8 8 1 4 . 1 8 5 7 . 5 6 3 5 . 8 1 1 5 7 . 0 . 8 7 8 7 0 0 . 0 0 8 4 4 1 9 . 3 3 4 1 0 . 0 1 3 4 . 2 9 8 9 9 1 . 0 0 0 5 7 0 . 0 2 3 1 6 2 5 . 0 5 8 1 4 . 7 5 1 2 . 6 7 4 1 4 1 . 1 6 8 8 2 0 . 0 3 0 6 9 2 7 . 2 6 3 1 6 . 5 6 5 2 . 2 8 9 2 6 . . . 1 . 2 1 9 2 0 . 0 . 0 4 7 7 6 2 9 . 9 6 7 1 8 . 6 6 3 1 . 7 4 4 8 9 1 . 2 7 0 9 9 0 . 0 7 1 4 6 3 2 . 9 3 7 2 0 . 7 9 1 1 . 3 1 3 1 7 1 . 3 1 7 6 8 p-(19B?4 3 5 . 3 4 9 ? ? . 5 6 9 1 . 0 1 5 4 5 1 .35351 0 . 1 5 3 3 2 3 9 . 9 9 2 2 6 . 0 7 8 0 . 6 6 3 2 3 1 . 4 1 6 2 8 0 . 1 9 1 3 2 4 2 . 6 3 7 2 8 . 0 5 4 0 . 5 1 5 8 6 1 . 4 4 7 9 9 0 . 2 3 2 8 6 4 5 . 7 9 9 3 0 . 4 6 9 0 . 4 0 0 5 8 . . . 1 . 4 8 3 8 6 . 0 . 2 9 7 7 6 5 0 . 8 4 9 3 4 . 3 5 2 0 . 2 7 6 8 2 1 . 5 3 5 9 6 0 . 3 4 3 0 5 5 4 . n o 3 6 . 6 6 9 0 . 2 1 5 8 9 1 . 5 6 4 3 0 0 . 4 0 9 0 5 5 9 . 9 8 3 4 1 . 1 1 2 0 . 1 5 0 7 2 1 . 4 1 3 9 6 . 0 . 4 7 5 7 0 6 5 . 4 4 1 4 5 . 3 8 6 0 . 1 0 4 1 1 1.65693 0 . 5 4 1 6 7 7 2 . 2 4 6 5 0 . 6 9 8 0 . 0 7 0 9 0 1 . 7 0 4 9 9 0 . 6 3 5 1 7 8 1 . 4 7 2 5 7 . 7 0 2 . 0 . 0 3 8 8 5 1 . :UJJBU9-0 . 7 3 3 4 7 9 7 . 7 2 0 6 9 . 7 6 0 0 . 0 1 8 1 2 1 . 8 4 3 7 3 0 . 8 0 9 9 4 .114 .725 6 1 . 4 4 9 0 . 0 0 8 3 8 1 . 9 1 3 5 4 0 . 8 7 6 2 0 1 3 4 . 1 3 5 9 4 . 3 2 1 0 . 0 0 3 2 9 1 . 9 7 4 6 1 UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE DRYING UNBEATEN PULP SHEETS WITH 5.3 X MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING 0 . 0 0 2 3 3 0 . 3 6 7 0 . 3 3 2 6 . 9 3 0 B 1 - 0 . 4 7 8 6 0 0 . 0 0 4 5 9 0 . 6 5 0 0 . 5 7 3 5.46491 -0.24169 0 . 0 1 3 6 4 0 . 6 7 0 0 . -J9S 3 . 4 7 9 0 3 - 0 . 2 2 5 4 5 0 . 0 1 8 0 7 1.061 0.957 3.03844 •0.01894 0 . 0 3 8 9 5 0 . B 7 2 0 . 7 6 6 1 . 9 B 6 6 0 ' - 0 . 1 0 4 5 9 0 . 0 4 7 9 5 1 . 3 2 6 1.209 1.74034 0,08231 0 . 0 5 7 8 5 0 . 9 7 4 0 . B B 3 1 .53191 - 0 . 0 5 4 1 6 0 . 0 7 1 0 5 1 .477 1 .351 1.31895 0.13070 0 . 0 9 7 0 5 1 .084 0 . 9 8 4 1 . 0 2 6 1 5 - 0 . 0 0 6 8 9 0 . 1 0 8 9 0 1 . 6 2 3 1 .4 88 0.92722 O. 17?A4 0 . 1 4 7 7 1 1 . 2 4 6 1. 138 0 . 6 8 9 8 9 0 . 0 5 6 1 3 0 . 1 6 5 1 0 1 . 6 5 0 1 .704 0.61191 0.23137 0 . 1 9 0 2 7 1 .339 . 1 . 2 2 5 0 . 5 1930 0 . 0 8 8 1 7 0 . 2 2 0 5 6 2 . 0 2 0 1 . 6 6 3 0.43096 0.27026 0 . P 4 7 4 7 1 . 4 8 9 1 .367 0 .367B1 f). l3- i7ft 0 . 2 7 8 8 8 2 . 2 3 1 2 . 0 6 3 0.30757 0.31459 0 . 3 0 8 9 6 1 . 6 4 6 1 . 5 1 5 0 . 2 6 0 2 0 0 . 18044 0 . 3 5 5 0 9 2 . 5 0 8 2 . 3 2 4 0 . 2 0 2 2 0 . 0.36626 0 . 4 0 7 7 6 I . 8 9 0 1 . 7 4 3 0 . 1 5 1 7 8 0 . 2 4 1 1 9 0.40192 2 . 6 7 5 2 . 4 8 1 0.15671 0.39457 0 . 4 8 6 8 2 2 . 1 0 0 1 .942 0 . U 9 7 7 4 ' 0 . 2 8 8 1 6 0 . 4 7 7 5 1 2 . 9 9 8 2 . 7 9 0 0.1Q3Q5. ... 0.44555 0 . 5 6 2 0 3 2 . 3 1 2 2 . 139 0 . 0 6 2 6 2 0 . 3 3 0 20 0 . 5 5 0 0 6 3 . 2 7 0 3 . 0 4 4 0.06739 0.48341. 0 . 6 4 2 2 0 2 . 5 2 9 2 . 3 3 7 0 . 0 3 6 9 9 0 . 3 6 8 7 0 0 . 6 2 6 9 4 • 3 . 5 6 8 3 . 3 1 9 0.04112 0.52103 j 0 . 7 6 4 5 0 2 . 768 2 . 5 3 7 0 . 0 1 3 6 0 0 . 4 0 4 4 0 0.68420 3 . 7 3 3 3 . 4 6 3 0.02716 0.53946 0 . 8 4 5 0 7 2 . 9 7 3 I . 6 9 3 0 . 0 0 5 3 4 0 . 4 3 0 1 8 0 . 7 7 3 1 3 4 . 0 7 0 3.759 0.01249 0.57502 0 . 8 4 7 4 8 4 . 2 6 3 3 . 8 8 9 0.0,0517 0.58982 : UNBEATEN PULP SHEETS WITH 144% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING UNBEATEN PULP SHEETS WITH 53jS% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING 0 . 0 0 0 5 3 0 . 0 0 P 8 0 0 . 788 1 .714 0 . 7 6 6 1 . 6 1 5 1 0 . 7 3 0 3 7 6 . b 1700 - 0 . 1 1 5 6 0 0 . 7 0 8 2 6 0 . 0 0 0 1 7 0 . 0 0 0 5 7 2 . 6 2 9 5 . 1 4 4 2 . 3 7 9 4 . 3 2 6 1 4 . 2 0 9 5 2 1 0 . 5 2 4 3 5 0 . 3 7 6 3 8 . 0 . 6 3 6 0 4 0 . 0 1 0 9 1 0 . 0 3 0 2 6 0 . 0 6 2 3 4 0 . 0 9 3 8 0 0 . 1 3 8 6 0 0 . 1 7 8 0 0 2 . 7 6 1 3 . 7 0 2 4 . 297 4 . 7 1 9 5 . 2 4 5 S . 7 0 4 2 . 5 6 6 3 . 4 9 B 4 . 0 7 1 4 . 4 7 7 4 . 9 8 5 5 . 4 3 0 3 . 8 5 0 1 3 2 . 3 0 7 7 6 1 . 4 5 2 5 9 1 . 0 5 6 3 7 0 . 7 3 6 5 7 0 . 5 6 1 8 7 0 . 4 1 2 6 9 0 . 5 4 3 8 7 0 . 6 0 9 7 5 0 . 6 5 1 0 2 0 . 6 9 7 6 8 0 . 7 3 4 8 4 0 . 0 0 2 0 0 0 . 0 0 6 3 5 0 . 0 1 3 1 6 0 . 0 2 9 3 7 0 . 0 4 6 5 3 0 . 0 6 6 7 0 6 . 8 5 0 1 2 . 9 0 9 1 6 . 4 0 9 1 9 . 9 1 9 2 2 . 3 9 8 2 3 . 6 1 3 6 . 2 3 1 • 7 . 0 3 5 1 0 . 0 2 6 1 2 . 7 8 5 1 4 . 8 0 2 1 5 . 7 7 9 • 7 . 2 8 4 4 4 4 . 8 2 7 8 0 2 . 3 4 7 3 2 1 . 7 2 6 5 7 1 .38266 - 0 . 7 9 4 3 6 . 0 . 6 4 7 2 6 1 . 1 0 6 70 j 1 . 1 7 0 3 l ! 1 . 1 9 8 0 7 0 . 2 2 0 3 0 0 . 2 6 9 1 0 0 . 3 4 2 7 0 0 . 4 1 0 4 0 0 . 4 7 6 2 0 0 . 5 5 8 6 0 6 . 1 5 7 6 . 6 4 2 7 .531 8 . 3 6 1 9 . 1 8 6 1 0 . 3 0 0 5 . 8 6 9 6 . 3 3 7 7 . 1 9 9 8 . 0 0 ) 8 . 8 0 3 9 . 8 8 0 0 . 4 3 1 6 3 0 . 3 2 5 0 0 0 . 2 1 6 3 0 0 . 14961 0 . 10382 0 . 0 6 396 0 . 7 6 8 5 6 0 . 8 0 1 9 0 0 . 6 5 7 2 5 0 . 9 0 3 1 3 0 . 9 4 4 6 5 0 . 9 9 4 7 5 0 . 0 8 3 3 0 0 . 1 0 0 2 0 0 . 1 1 6 4 0 0 . 1 6 1 0 0 0 . 1 9 7 1 0 0 . 2 3 1 3 0 2 5 . 2 2 5 2 6 . 4 5 7 2 7 . 5 5 8 3 0 . 2 7 5 3 2 . 3 7 7 3 4 . 3 8 0 - 1 6 . 8 9 8 1 7 . 8 5 8 1 8 . 7 5 7 2 0 . 8 6 4 2 2 . 5 3 1 2 4 . 1 2 2 1 . 1 6 5 0 0 0 . 9 9 8 2 7 0 . 8 7 2 4 4 _ 0 . 6 2 9 1 3 0 . 4 9 7 4 7 0 . 4 0 4 2 7 1 . 2 2 7 8 2 . 1 . 2 5 1 8 4 U 21316 , 1 . 3 1 9 3 9 1 . 3 3 2 7 8 1 . 3 6 2 4 1 0 . 6 3 6 4 0 0 . 7 1 6 5 0 0 . 7 7 3 5 0 11 . 2 7 6 1 2 . 2 5 4 1 2 . 7 0 4 1 0 . 8 1 2 1 1 . 7 3 3 1 2 . 1 3 1 0 . 0 3 8 5 2 0 . 0 2 0 6 1 0 . 0 1 2 4 4 1 . 0 3 3 9 2 1 . 0 6 9 4 0 1 . 0 B 3 8 9 0 . Z 8 2 1 0 0 . 3 7 5 2 0 0 . 4 4 3 3 0 0 . 5 3 9 7 0 0 . 6 2 8 3 0 0 . 6 9 7 2 0 3 7 . 6 2 1 4 4 . 0 1 3 4 9 . 3 1 3 5 8 . 1 5 1 6 8 . 6 9 4 7 8 . 1 4 3 2 6 . 7 5 1 3 1 . 8 5 3 3 6 . 2 5 9 4 3 . 7 4 5 ' 5 2 . 5 8 2 6 0 . 3 7 8 0 . 3 0 2 0 6 0 . 18125 0 . 1 2 4 8 2 0 . 0 7 1 7 4 0 . 0 4 0 7 4 0 . 0 2 4 5 4 - 1 . 4 2 7 3 3 1 . 5 0 3 1 5 1 . 5 5 9 4 2 1 . 6 4 0 9 3 | 1 . 7 2 0 8 4 1 . 7 6 0 8 8 1 0 . 7 6 3 5 0 0 . 8 2 0 B 0 , 0 . 8 7 6 3 0 8 9 . 3 0 5 9 9 . 8 2 1 1 1 1 . 0 3 9 .. ... 6 9 . 5 8 5 7 7 . 2 4 7 8 4 . 3 3 8 . . O . Q l 3 > 3 0 . 0 0 7 3 6 . 9^ft012___ 1 . 6 4 2 5 1 ' l ; 8 8 7 8 8 1 -243-TABLE I. CONTINUED CYLINDRICAL PORE MODEL UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION p p. vads. mts(S.TPj/9 0.00014 0.000 82 3.306 8 .566 2.970 6 .679 14.85232 9.52454 0.47278 0.82473 0.00417 0.01250 0.03580 0.05330 0.08420 0. 13150 17.334 2 5.70 5 33.517 37.137 40.983 45.839 9.749 15.425 21.621 24.587' 27.406 3 1 . 172 5.66375 3.62175 2.09125 1.62122 1.15495 0.77629 0.98894 1.18823 1.33488 1.39070 1.43 78 5 1.49377 0.17490 0.21300 0.25230 0.29530 0.33900 0.40820 49.627 53.245 56.5 77 60.62 3 64.619 71 .767 34.03 8 36.908 39.470 42 .672 45.678 51.194 0.57337 0.45107 0.35770 0.28 06 2 0.2207 1 0.15142 1. 53196 1.56713 1.59626 1,63015 1.65970 1.70922 0.47230 0.53870 .0 .60040 0.66980 0 .73860 0.7 8940 79.399 . 88.118 97.721 110.840 12 7.300 141.190 57.585 64.705 72 .474 83.015 96.582 107. 177 0.10613 0.07217 0.0 4909 0.0 30 30 0.01732 0.01055 1.76031 1 , 810 94 1.86018 1.91916 1 .98489 2.03010 0 .83380 0.88120 155.3 40 176.8 90 117.364 132.615 0.00623 0.00302 2.06953 2.122 59 -244-TABLE2: B.E.T. AND DUBININ (OR KAGANER) DATA UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 5 . 6 3 4 1 . 1 5 4 , 3 . 1 7 3 1 . 1 6 0 2 . 4 7 6 1 . 4 8 7 2 . 1 1 1 1 . 3 5 9 2 . 0 9 8 1 . 5 2 5 2 . 0 3 6 1 . 3 6 7 0 . 0 T 0 9 0 . 0 0 1 9 5 4 1 . 3 2 1 1 . 5 9 2 0 . 0 7 B 6 0 . 0 0 2 4 7 5 1 . 2 1 7 1 . 5 3 9 0 . 0 9 3 3 0 . 0 0 2 4 7 0 1 . 0 6 1 1 . 6 2 0 0 . 0 9 2 0 0 . 0 0 2 6 9 B 1 . 0 7 4 1 . 5 7 5 0 . 1 1 8 7 0 . 0 0 3 0 3 3 0 . 8 5 7 1 . 6 4 7 1 0 . 1 2 7 9 0 . 0 0 3 5 2 1 0 . 7 9 8 1 . 6 1 9 0 . 1 6 2 1 0 . 0 0 4 0 0 3 0 . 6 2 4 . 1 . 6 8 4 ' 0 . 1 6 0 0 0 . 0 0 4 1 4 6 0 . 6 3 4 1 . 6 6 2 0 . 2 1 5 5 0 . 0 0 5 1 5 1 0 . 4 4 4 1 . 7 2 7 0 . 2 3 7 4 0 . 0 0 5 8 3 2 0 . 3 9 0 . 1 . 7 2 7 0 . 2 7 7 7 0 . 0 0 6 5 6 3 0 . 3 1 0 1 . 7 6 8 0 . 2 6 2 1 . 7 8 3 0 . 2 3 5 1 . 6 0 4 0 . 1 3 4 1 . 8 7 1 0 . 1 6 9 1 . 8 4 3 0 . 1 1 9 1 . 8 8 8 0 . 1 0 5 1 . 9 0 1 0 . 0 9 3 , 1 . 9 2 1 4.650 0.933 3.643 1.143 2.032 1.419 1.996 1.439, 0.0877 0.002485 1.117 1.588 0.0989 0.002653 1.010 1.617 n.?D4l 0.0O474A 0.474 1.732 0.2449 0.005453 0 . 3 7 3 1.774 0.2999 0.006489 0*274 1.820 0.199 1.870 0.154 1.912 0.107 1.969 0.069 2.038 UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 14.852 0.519 5.553 0.879 9.525 0.933 3.648 1.127 5.664 1.239 2.550 1.329. 3.622 1.410 1.734 1.459 2.091 1.525 0.0742 0.002296 1.276 1.543 n.'nm * i 6 1 .fc?l 1 .S70 0.1 ?*s 0.003319 0.81 9 1.632 0.0842 0.002243 1.155 1.613 0.1533 0.003874 0.662 1.670 0.1315 0.003303 0.776 1.661. 0.1976 0.004792 0.496 1.711 0.1749 0.004271 0.573 1.696 0.2314 0.005432 0.404 1.744 0.2130 0.009063 0.451 1.726 0.267 1.795 0.2523 0.005964 0.358 1.753 0.209 1.830 0.2953 0.006912 0.281 1.783 0.164 1.865 0.221 1.810 0.119 1.908 0.151 1.856 0.087 1.949 0.106 1.900 0.072 1.445 PULP BEATEN I MINUTE —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 8.849 0.954 3.265 1.148 6.034 1. 196 2.061 1.377 2.951 1.443 0.0740 0.002325 1.279 1.536 0.0504 0.001533 1.684 1.539 0.1359 0.003764 0.751 1.621 0.0785 0.002216 1.221 1.585 0.1752 0.004601 0.572 1.664 0.1286 0.003413 0.794 1.636 0.27117 0.00578R 0.1717 0.004404 0.586 1.673 0.2737 0.006796 0.317 1.744 0.2222 0.005588 0.427 1.708 0.256 1. 774 0.2818 0.007009 0.303 1.748 0.170 1.829 0.216 1.789 6.122 1.872 0.158 1.827 0.068 1.915 0.111 1.670 0.077 1.909 0 . 0 5 1 0 0 . 0 0 1 8 3 6 0 . 1 0 2 6 0 . 0 0 2 9 1 9 0 . 1 7 5 0 0 . 0 0 4 3 3 8 . 0 * 2 0 9 6 0 . 0 0 A 3 2 . 5 _ 4.244 2.624 1.670 0.976 0.573 0.4^L_ 0.265 0.189 0 . 1 1 3 0.075 0.951 1.231 1.467. . 1.593! 1.689 • 731 1.607 1.861 1.939 2.002 PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 11 .137 0.805 5.649 0.716 7.757 1.046 3.469 1.132 3.245 1.386 1.999 1.362 2.818 1.419 0.0933 0.003073 1.061 1.525 1.730 1.505 0.1167 0.003603 0.870 1.564 0.0771 0.002326 1 .239 1.1SS n.iRhs 0.005217 0.539 1.637 0.1377 0.003892 0.741 1.613. 0.2457 0.006631 0.372 1.691 0.1883 0.005145 0.526 1.654 0.2891 0.007686 0.290 1.723 0.2491 0.006648 0.364 1.698 0.215 1.765 0.247 1.739 0.168 1.801 0.166 1.788 0.124 1.837 0.112 1.834 0.092 1.874 0.077 1.881 0.073 1.905' 3 . 3 1 4 1 . 1 1 2 0 . 0 5 8 1 0 0 0 2 1 8 8 1 . 5 2 7 1 . 4 5 0 0 . 1 0 4 9 0 0 0 3 2 5 3 0 . 9 5 9 1 . 5 5 6 0 . 1 4 0 8 0 0 0 4 0 1 6 0 . 7 2 5 1 . 6 1 1 : 0 . 1 6 9 9  0 0 4 5 8 4 0 . 5 9 3 1 . 6 5 0 0 . 2 3 3 5 0 L Q 0 5 9 4 2 0 . 3 9 9 1 . 7 1 0 0 . 2 8 6 0 0 . 0 0 6 9 7 2 0 . 2 9 6 1 . 7 5 9 0 . 2 0 1 1 . 8 1 3 0 . 1 3 6 1 . 8 7 3 0 . 0 8 4 1 . 9 4 7 PULP BEATEN S MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 12.214 0.812 5.750 0.764 6.47B 1.187. 4.185 1.000 3.698 1.371 2.645 1.255 3.438 1.398 1.720 1.406 2.276 1.475 O.0898 0.003022 1.096 1.514 o-nOPOB? 1 .381 0.1102 0.063516 0.917 1.547 0.L029 0.003016 0.975 1.580 0.1456 0.004402 0.700 1.588 0.1519 0.004360 0.670 1.614 0.1877 0.005453 0.52B 1.627 0.2037 0.005767 0.477 1.647 0.2451 0.006940 0.373 1.670 0.2625 0.007439 0.337 1.6B0 0.249 1.720 0.207 1.725 0.194 1.752 0.138 1.767 0.193 1.752 0.093 l.BOB 0.137 1.793 0.103 1.B28 PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION B.596 0.925 3.503 1.041 5.812 1.152 2.327 1.258 4.299 1.286 0.0629 0.002592 1.443 1.413 2.674 1.399 0.11D4 0.003759 0.916 1.519 2.289 1.436 0.1381 0.00443* 0.739 1.558 1.745 l.*77 0.18S6 0.005671 0.0715 0.002337 1.313 1.518 .0.2177 0.006432 0.438 ~ 1.636 0.0982 0.003082 1.015 1.548 0.2476 0.007168 0.368 1.662 0.1533 0.00452 6 0.663 1.602 0.2947 0.008464 0.282 1.693 0.1913 0.005549 0.516 1.630 0.231 1.722 0.2329 0.006628 0.401 1.661 0.195 1.745 n.?Q76 n.nnA^3« 0.277 1.706 0.166 1.767 0.216 1.733 0.116 1.813 0.151 1.776 0.078 1.859 0.104 1.816 0.071 1.859, -245-TABLE 2. CONTINUED • VACUUM ORIEP UNBEATEN PULP SHEETS N I T R O G E N _P P P. 7 ^ 0 . 0 7 2 1 1 . 0 9 3 9 0 . 1 1 4 9 1 . 3 2 5 3 0 . 1 7 4 6 1 . 9 9 5 4 B . J 1 3 1 2 . 2 B 9 4 0 . 2 9 7 0 2 . 0 9 3 1 0 . 0 9 9 4 1 . 8 6 9 8 0 . 1 4 0 9 1 . 8 0 2 8 0 . 1 6 5 5 1 . 9 2 5 7 . 0 . 2 4 8 3 2 . 7 3 0 4 0 . 0 8 7 8 0 . 1 3 5 2 0 . 2 0 5 2 0 . 2 5 1 6 1 . 5 7 8 5 1 . 6 9 9 1 2 . 2 4 5 0 2 . 7 3 2 9 2 - 8 9 7 3 0 . 0 8 8 2 1 . 8 5 9 1 0 . 1 2 2 4 1 . 5 0 7 1 0 . 1 5 8 7 2 . 2 1 9 2 0 . 2 0 9 1 2 . 2 7 9 3 2 . 6 4 5 7 UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE DRYING 6.931 -0.433 3.030 -0,376 3.479 -0.174 2.016 -0.1B4 1.987 -0.059 0.0741 0.09108 1.277 -0.056 0.0578 0.06304 1.532 -0.011 0.0968 0.1071 1.029 0.0 . 0.0971 0.09916 1.026 0.033 0.1427 0.1415 0.715 0.070 n . t*77 n . H 9 l (1.690 0.096 0.1972 0.1816 0.497 0.131 0.1903 0.1735 0.519 0.127 ' 0.2586 0.2278 0.345 0.183 0.2475 0.2209 0.368 0.173 0.2967 0.2509 0.279 0.226 0.260 . 0.216 0.203 0.269 0.152 0.276 0.135 0.319 0.098 0.322 0.093 0.366 P *. 0 . 0 6 5 4 0 . 1 2 3 7 0 . 1 5 76 0 . 2 3 8 8 0 . 2 8 1 8 0 . 0 8 2 6 6 0 . 1 2 3 8 0 . 1 4 2 3 0 . 1 9 4 7 0 . 2 1 7 3 2 . 2 5 9 1 . 4 0 2 0 . 8 2 4 0 . 6 4 4 0 . 3 8 7 0 . 3 0 3 - 0 . 2 3 9 - 0 . 0 7 2 0 . 0 5 7 0 . 1 1 8 0 . 2 0 7 0 . 2 5 7 0 . 2 4 1 0 . 1 7 3 0 . 1 1 9 0 . 0 8 3 0 . 2 9 4 0 . 3 4 7 0 , 4 0 3 0 . 4 4 7 UNBEATEN PULP SHEETS WITH 5 . 3 % MOISTURE 9 . 4 6 5 - 0 . 1 8 7 3 . 0 3 8 0 . 0 2 6 1 . 7 4 0 0 . 1 2 3 0 . 0 7 1 0 0 . 0 3 1 7 8 1 . 3 1 9 0 . 1 6 9 0 . 1 0 8 9 0 . 0 7 5 3 0 0 . 9 2 7 0 . 2 1 0 0 . 1 6 5 1 0 . 1 0 6 9 0 . 6 1 2 0 . 2 6 7 0 . 2 2 0 6 0 . 1 4 0 1 0 . 4 3 1 0 . 3 0 5 0 . 2 7 8 9 0 . 1 7 3 3 0 . 3 0 8 0 . 3 4 B 0 . 2 0 2 0 . 3 9 9 0 . 1 5 7 0 . 4 2 7 0 . 1 0 3 0 . 4 7 7 TO SOLVENT EXCHANGE DRYING 3 . 2 3 5 - 0 . 2 7 2 2 . 4 2 6 - 0 . 0 6 5 0 . 0 7 8 8 0 . 0 6 0 7 5 1 . 2 1 8 0 . 1 4 4 0 . 1 0 0 4 0 . 0 7 0 8 2 0 . 9 9 7 0 . 1 9 6 0 . 1 7 0 5 0 . 1 0 7 1 0 . 5 9 0 0 . 2 8 3 ft,7W\? Q P l ^ 5 f l 0,. 4Q7 Q , 3 4 3 0 . 2 3 9 0 . 4 1 8 0 . 1 6 5 0 . 4 7 0 0 . 1 3 1 0 . 5 0 2 0 . 1 0 0 0 . 5 3 8 UNBEATEN PULP SHEETS WITH 14.4% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING 0,0623 0.01347 0.0938 0.02193 1 0 . 7 3 0 6 . 5 1 7 3 . 8 5 0 2 . 3 0 6 1 . 4 5 3 . 0 5 6 0 . 5 6 8 0 . 6 3 3 , 0 . 6 7 4 0 . 1 3 8 6 0 . 0 3 0 6 8 0 . 1 7 B 0 0 . 0 3 7 9 6 0 . 2 2 0 3 0 . 0 4 3 6 9 0 . 2 6 9 1 0 . 0 5 5 4 3 0.737 0.562 0.432 0.325 0.216 .150 . 0 . 7 2 0 0 . 7 5 6 0 . 7 8 4 0 . 8 2 2 0 . 6 7 7 0 . 9 2 2 0.104 0.963 UNBEATEN PULP SHEETS WITH 33^6% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING 14.210 0.420 10.524 0.711 7.284 0.947 4.82B 1.111 3.537 1.215 ?.147 1.299 1.727 1.350 0.0667 0.003001 1.383 1.377 0.0833 0.003602 1.165 1.402 0.1002 0.004209 0.998 1.423 0.1164 0.004760 0.872 1.440 n . l M f l 0.006438 O.A29 1.481 0.1971 0.007582 0.497 1.510 0.2313 0.008752 0.404 1.536 0.2821 0.0104S 0.302 1.575 O . l j l 1.644 0.125 1.693 0.072 1.765 APPENDIX H t-PLOT DATA UNBEATEN PULJ>—SCtytVfEXCMA«ISE DRIED F R O ! WATER SUSPENSION; UNBEATEN PULP—SOLVENT EXCHANGE OWED FROM WATgSUSPSISlOW JtiL ; x ! - . ; * > l ; s r a * : - • } . . p i ; * - . • i ! n.nn*.9*n l*-74? 0.\77 0.370 0.000140 1.1(16 (1.(175 0.026690 30.710 0.694 J 0.854 I 0.000820 8.566 0.193 . 0.140 0.035600 33.514 0.757 0.884 0.004170 17.334 0.391 0.564 j 14.A47 O-HA? 0.9A5 n.n*->*nn »5.7A5 P-*79 QrTJL« 0.093300 41.664 0.941 1.026 0.O3580O 33.517 0.753 0.885 0.118700 44.411 1.003 1.064 0.053300 37.137 0.637. 0.934 . 0.162100 411.377 1.091 1.141 40.983 (1.974 1.010 0.215500 53.327 1.204 " . ' * \ 1.219 1 0.131300 45.839 1.033' 1.091 0.277700 58.579 1.323 1.310 0.174900 49.627 1.118 1.160 • n.*??son 63.635 1 .437 1.393 53.745 l.?00 1.715 0.387800 69.692 1.574 1.443_ 0.252300 56.577 1.273 1.273 0.473600 79.570 1.797 1.625 0.295300 60.623 1.366 1.336 t\. 51770ft ftA.R41 1 .461 1.727 0.434000 64.619 1.4*56. 1.409 0.625700 101.729 2.297 1.944 0.408200 71.767 1.617 1.531 0.701800 1 IB.505 2.676 2.165 0.472300 79.399 1 .789 1.623 I n . 7 7 n n o l l&.TI f t 3.0H7 2.439 0.538700 88.118 1.986 1.742 0.817100 150.645 3.402 2.706 0.600400 97.721 2.202 1.878 0.897900 187.589 4.236 3.520 0.669800 110.840 2.498 |2.070 0.738600 127.300 7. 869 |2.2B5 0.789400 141 . ISO 3.18Z 0.833800 155.340 3.501 {2.825 0.881700 176.890 3-487 3.294 PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION PULP BEATEN 9 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 6.1B7 0 . 1 6 5 ( l . O f l l n.(inni?o 6 . 4 4 1 O. 179 O.OS6 0.001640 11.120 0.288 0.266 0.002650 15.382 0.425 0.426 0.015797 24.345 0.630 0.798 0.011940 - 23.493 0.649 0.758 0 . 0 ? O 9 , 5 ? 7 6 . 7 3 3 D . 6 7 9 0.823 ft.013990 7 S . 0 7 6 - ft.691 0.7ft? 0.048383 31.996 0.628 0.919 0.031000 29.868 0.825 0.870 0.077106 35 .917 0.929 0.997 0.066800 34.377 0.949 0.973 0.137716. 41 .039 1.067 1.104 f l . l f t ? 9 0 f t 18 .017 1.050 1.046 0.188343 45 .104 1.167 1.179 0.151900 41 .084 1.134 1.127 0.249137 49.410 1 .291 1.268 0.203700 44 .356 1.225 1.202 0.318773 54.747 1 .418 . 1.378 • 0.767S00 47.848 l . 1 7 1 1.28R 0.390860 61.310 1.586 1.499 0.351000 53.081 1 .466 1.431 0.462181 68.266 1.766 1.608 0.425200 58.539 1.616 1 .554. 0.578069 76.043 1.967 1.718 (1.44610n 6 4 . 7 9 4 1 . 7 7 5 1.65R 0.585515 83.017 2.146 1.846 0.569200 71.558 1.976 1.812 0.640772 92.213 2.386 1.986 0.676200 85.129 2.350 2.089 (1.701943 1 0 4 . 0 0 ? 7 . 6 9 1 7.166 O. 756600 9 8 . 1 ? 0 7.709 2.355 0.754343 115.673 2.993 2.344 0.856900 122.192 3.374 3.016 0.804528 128.952 3.336 2.626 O.84157* 147.471 3.665 2 .898 0.666387 153.180 3.963 3.117 PULP BEATEN I MMUTE—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION j ' W • Il ^ In.ftrtiAAO 11.966 0.714 j 0.179 10.003496 15.695 0.376 0.498J. 0.019144 27.720~ ^  6.664 1 0.815 n.n*oi7f l 1 * . AIT ft.^7 9 0.979 '0.076490 38.430 0.920 1.000 0.128575 43.226 1.035 ( 1.066 ft.1716ft? 1 .177 0.222156 51.107 1.224 1.229 0.281775 55.970 1.341 1.316 n . i4?Aft5 - t.\ .511 1 . 4 7 * 1.41* 0.400512 67.219 1.610 1.518 0.464605 74.191 1.777 1.612 0-578668 81.031 1 . 9 * 1 1.719 0.625758 94.532 2.264 1.944 0.703266 110.785 2.654 2.170 0.777791 178.212 3.071 2.463 0.836500 144.768 . 3.467 2.845 PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION " 0,,pQil70 8.41 1 0.2B1 0. 196 0.003884 14.185 0.474 0.538 0.008445 19.334 0.647 0.754 .0.073159 25..05 8 Il*fl2fl 0.837 . 0.030688 27.263 0.912 0.B68 0.047759 29.967 l.OOZ 0 .9 la _m7.l46Q J 3?..437 1-11)7 . 0.48 6, . 0.098244 35.344 1.162 1.037 0.153325 39.992 1.338 1.129 ' 0.191371 4? .63 7 1.476 1.184. 0.232857 45.799 1.532 .1.244 0.297760 50.B49 1.701 1.339 0.343055 54.110 1.610 1.416 0.409048 59.983 2.006 1.532 0.475702 65.441 2.189 1.628 0.541673 72.246 2.416 1.749 0.635172 81.972 2.742 j 1.970 0.733475 97.720 3.266 2.268 P.60993B , 114.72S 3 _ .B3J 2 ^ 6 1 . 0.876200 134.135 4.486 3.232 -247-t-PLOT DATA CONTINUED U N B E A T E N P U L P S H E E T S — V A C U U M D R I E D PRIOR TO S O L V E N T E X C H A N G E DRYING U N B E A T E N P U L P S H E E T S W I T H 5 . 3 % M O I S T U R E P R I O R T O S O L V E N T E X C H A N G E O R Y I N G p p. STO«y P ' P . ! V 0 . 0 0 2 3 3 0 0 . 3 6 7 0 . 3 0 9 0 . 3 6 1 0 . 0 0 4 5 9 5 0 . 6 5 0 '• 0 .6O1 0 . 0 1 3 6 3 9 0 . 6 7 0 0 . 5 6 4 0 . 7 7 8 0 . 0 1 8 0 6 7 1 . 0 6 1 0 . 6 3 3 0 . 8 1 1 ' 0 . 0 3 6 9 5 2 0 . 8 7 2 0 . 7 3 5 0 . 8 9 3 0 . 0 4 7 9 4 9 1 . 3 2 6 0 . 7 9 1 0 . 9 1 8 0 . 9 7 * n . n ? l 0 . 4 4 7 0 . 0 7 1 0 4 7 1 . 4 7 7 0 . 8 8 1 0 . 9 8 5 • 0 . 0 9 7 0 5 3 1 . 0 8 4 0 . 9 1 3 1 . 0 3 5 0 . 1 0 8 9 0 4 1 . 6 2 3 0 . 9 6 8 1 . 0 5 5 0 . 1 4 7 7 0 B 1 . 2 4 6 1 . 0 5 0 1 .121 0 . 1 6 5 1 0 3 1 . B 5 0 1 . 1 0 3 1 . 1 4 6 n . l Q( i77* l . V * 9 l . i? f t 1 . 1 8 7 • 0 . 7 7 0 5 5 f t ? . f t ? 0 1 . 2 0 4 1 . 2 2 6 0 . 2 4 7 4 7 * 1 . 4 8 9 1 . 2 5 4 1 . 2 6 6 0 . 2 7 8 8 7 7 2 . 2 3 1 1 . 3 3 0 1 . 3 1 2 0 . 3 0 8 9 6 1 1 . 6 4 6 1 . 3 8 7 1 . 3 5 9 0 . 3 5 5 0 9 0 2 . 5 0 8 1 . 4 9 6 1 . 4 3 9 0 . * 0 7 7 6 1 1 . 8 9 0 1 . 5 9 ? 1 . 5 3 0 ft.&fl141A ?.h7«» 1 . 1 9 4 i . w i 0 . 4 8 6 B 2 4 2 . 1 0 0 1 . 7 6 9 1 . 6 4 4 0 . 4 7 7 5 0 9 2 . 9 9 8 1 . 7 8 8 1 . 6 3 1 0 . 5 6 2 0 2 6 2 . 3 1 2 1 . 9 4 8 1 . 7 9 6 0 . 5 5 0 0 5 6 3 . 2 7 0 1 . 9 5 0 1 . 7 7 1 0 . A 4 7 7 0 5 2 . 5 7 9 2. 131 1 . 9 9 0 ' 0 . 6 2 6 9 4 1 3 . 5 6 8 7 .17ft 1 . 9 4 7 0 . 7 6 4 4 9 7 2 . 7 6 B 2 . 3 3 2 2 . 3 9 3 0 . 6 8 4 2 0 4 3 . 7 3 3 2 . 2 2 6 ' 2 . 1 1 2 0 . 8 4 5 0 6 7 2 . 9 7 3 2 . 5 0 5 2 . 9 0 9 0 . 7 7 3 1 2 7 0 . 8 4 7 4 8 2 4 . 0 7 0 4 . 2 6 3 2 . 4 2 7 < t *42 2 . 4 3 8 2 t ? 2 8 U N B E A T E N P U L P S H E E T S W I T H 14 .4% M O I S T U R E PRIOR T O S O L V E N T . E X C H A N G E DRYING U N B E A T E N P U L P S H E E T S W I T H 3 3 j S % M O I S T U R E PRIOR TO S O L V E N T E X C H A N G E D R Y I N G 0 . 0 0 0 5 3 0 0 7RH 0 0 0 9 ? 0 . 0 0 0 1 7 0 2 . 6 2 9 0 . 0 9 3 0 . 0 3 0 0 . 0 0 2 8 0 0 1 . 7 1 * 0 . 3 3 5 0 . 4 2 0 0 . 0 0 0 5 7 0 5 . 1 4 4 0 . 1 8 3 0 . 0 9 9 0 . 0 1 0 9 1 0 2 . 7 6 1 0 . 5 4 0 0 . 7 4 3 0 . 0 0 2 0 0 0 8 . 8 5 0 0 . 3 1 4 " 0 . 3 1 7 O.O307AO -\ 70? 0 775 0 Rf>7 r t . oo f . ^5n 1 7 . 9 0 9 0 . 4 5 9 0 . 7 0 9 0 . 0 6 2 3 4 0 4 . 2 9 7 0 . 8 4 1 0 . 9 6 0 0 . 0 1 3 1 6 0 1 6 . 4 0 9 0 . 5 8 3 0 . 7 7 3 0 . 0 9 3 8 0 0 4 . 7 1 9 0 . 9 2 4 1 . 0 2 9 0 . 0 2 9 3 7 0 1 9 . 9 1 9 0 . 7 0 8 0 . 8 6 4 0 . 1 3 8 6 0 0 5 . 7 4 5 1 0?7 U 0 f l 6 _ 0.0*R<*™ 7 7 . 1 9 8 0.79fc f l . 4 ? 0 0 . 1 7 8 0 0 0 5 . 7 0 4 1 . 116 1 . 1 6 4 0 . 0 6 6 7 0 0 2 3 . 8 1 3 0 . 8 4 6 0 . 9 7 3 0 . 2 2 0 3 0 0 6 . 1 5 7 1 . 2 0 5 1 . 2 2 6 0 . 0 8 3 3 0 0 2 5 . 2 2 5 0 . 8 9 6 1 . 0 0 8 0 . 2 6 9 1 0 0 6 . 6 4 2 1 . 3 0 0 1 . 2 9 7 n.iofl?no ?*.-AS 7 A . 9 4 D 1 .041 0 . 3 4 2 7 0 0 7 . 5 3 1 1 . 4 7 4 1 . 4 1 5 0 . 1 1 6 4 0 0 2 7 . 5 5 8 0 . 9 7 9 1 .066 0 . 4 1 0 4 0 0 8 . 3 6 1 1 . 6 3 7 1 . 5 3 4 0 . 1 6 1 0 0 0 3 0 . 2 7 5 1 . 0 7 6 1 . 140 0 . 4 7 6 2 0 0 9 . 1 B 6 1 . 7 9 8 1 629 0 . 1 4 7 1 0 0 1 7 . 3 7 7 Itl 50 1 . 1 9 2 0 . 5 5 8 6 0 0 1 0 . 3 0 0 2 . 0 1 6 1 . 7 8 9 0 . 2 3 1 3 0 0 3 4 . 3 8 0 1 .221 1 . 2 4 2 0 . 6 3 6 4 0 0 11 . 2 7 6 2 . 2 0 7 1 . 9 7 4 ' 0 . 2 8 2 1 0 0 3 7 . 6 2 1 1 . 3 3 7 1 . 3 1 6 n . 7 1 f l s n n 1? 7 199 ? ?1B n.V7«i?nn 4 4 . 0 1 3 1 . 5 6 4 1 . 4 7 2 0 . 7 7 3 5 0 0 1 2 . 7 0 4 2 . 4 8 7 2 . 4 * 0 0 . 4 4 3 3 0 0 4 9 . 3 1 3 1 . 7 5 2 1 . 5 8 1 6 . 539700 5 8 . 1 5 1 2 . 0 6 6 1 . 7 4 4 n.fi?mno A B . A 9 4 ? . * 4 1 1 . 9 5 1 0 . 6 9 7 2 0 0 7 8 . 1 4 3 2 . 7 7 6 2 . 1 5 1 0 . 7 6 3 5 0 0 8 9 . 3 0 5 3 . 1 7 3 2 . 3 8 8 n . n ? n n n o 9 9 . B 7 1 3 . 5 4 6 7 . 7 3 4 0 . 8 7 6 3 0 0 111 . 0 3 9 3 . 9 4 5 3 . 2 3 3 -248-APPENDIX H Table 2: Comparison o f " t " - P l o t V a l u e s U s i n g the D i f f e r e n t " S t a n d a r d " Isotherms Unbeaten S o l v e n t Exchange D r i e d Prom S u s p e n s i o n Sample S t a n d a r d I s o t h e r m Used v/v * m Payne & S i n g L i p p e n s et a l Pierc< (17D (110) (48) 0.00014 0.075 0.00082 0.193 0.00417 0.391 0.564 0.0125 0.579 0.765 0.0358 0.755 0.885 0.0533 0.837 0.934 0.0842 0.924 1.010 1.008 0.1315 1.033 1.091 1.105 0.1749 1.118 1.160 1.186 0.2130 1.200 1.215 1.256 1.271 0.2523 1.275 1.273 1. 328 1.326 0.2953 1.366 1.336 1.407 1.386 0.3390 1.456 1.409 1.487 1.448 0.4082 1.617 1.531 1.630 1.551 0.4723 1.789 1.623 1.774 1.654 0.5387 1.986 1.742 1.924 1.774 0.6004 2.202 "1.878 2.080 1.903 O.6698 2.498 2.070 2.299 2.078 0.7386 2.869 2.285 2. 611 2.300 0.7894 3.182 2.531 2.908 2.517 0.8338 3-501 2.825 3.292 2.770 0.8812 3.987 3.294 3.923 3.160 * v c a l c u l a t e d from B.E.T. e q u a t i o n APPENDIX I Study on t h e E f f e c t s o f P o s s i b l e E r r o r s l n V o l u m e t r i c A p p a r a t u s T h i s s t u d y e s t i m a t e d t h e p o s s i b l e e r r o r i n a s i n g l e r e a d i n g and assumed i t would always o c c u r . The e s t i m a t e d e r r o r s were combined t o g i v e t h e w o r s t p o s s i b l e c a s e . One r u n was c a l c u l a t e d t h r o u g h from p r i m a r y d a t a . The r e s u l t s o f t h e s e c a l c u l a t i o n s a r e g i v e n below. Assumed E r r o r s : P r e s s u r e Manometer - 0.005 cm. At m o s p h e r i c P r e s s u r e ± 0.010 cm. Temperature ± 0.2 °P Dead Volume ± 0.2 JS Sample Weight ± 0.2 % R e s u l t s o f E r r o r C a l c u l a t i o n s C a l c u l a t e d V a r i a b l e H i g h Mean Low B.E.T. S u r f a c e A r e a (sq.m./g.) 195.1 193-2 191-7 P i e r c e Pore A n a l y s i s ( P a r a l l e l s i d e d f i s s u r e model assumed) C u m u l a t i v e Pore Volume ( m i s . ( S . T . P . ) / g . ) 170.1 168.7 167.6 C u m u l a t i v e Pore A r e a (sq.m./g.) 115-8 114.9 114.3 Large W a l l S e p a r a t i o n ( a ) 213 212 211 Most Common Pore S i z e (ft S e p a r a t i o n ) 25-16 25-15 25-14 U n c o r r e c t e d D u b i n i n P l o t I n t e r c e p t ( m i s . ( S . T . P . ) / g . ) 50.9 50.1 49.1 -250-APPENDIX J E x t r a p o l a t i o n o f Argon B u l k L i q u i d P r o p e r t i e s t o 78 °K. The f o l l o w i n g d a t a i s g i v e n i n B a r r o n (164) f o r t h e p r o p e r t i e s o f Argon and Oxygen. Temperature Argon D e n s i t y Heats o f V a p o u r i z a t i o n • ° R. l b ./cu. f t . B . t . u . / l b . m m Argon Oxygen 220 71.4 53.3 73.2 , 200 77.1 59.6 80.6 190 79-8 62.4 180 82.42 65.0 87.4 170 84.66 67.1 160 86.91 69.1 92.2 15.7.1 87.56 69-5 155 88.03 69.8 140 96.6 A p l o t o f d e n s i t y v e r s u s t e m p e r a t u r e r e v e a l e d a l i n e a r p l o t . T h i s was e x t r a p o l a t e d t o 78 °K (140.3 t o y i e l d a d e n s i t y o f 90.65 l b . / c u . f t . (1.452 g . / c c . ) . Heat o f V a p o r i z a t i o n : A p l o t o f the l o g o f the heat of vapour-i z a t i o n o f argon v e r s u s the l o g o f the heat o f vapour-i z a t i o n o f oxygen i s l i n e a r o v e r the range 160 220 °R, T h i s was e x t r a p o l a t e d on t h e oxygen d a t a t o determine an e s t i m a t e o f the heat o f v a p o u r i z a t i o n o f argon at 140.3 °R. The v a l u e o b t a i n e d from t h i s e x t r a p o l a t i o n was 72.6 B . t . u . / l b . • S u r f a c e T e n s i o n : The e x t r a p o l a t e d s u r f a c e t e n s i o n v a l u e , 14.9 dynes/cm. was t a k e n from the work of Emmett and,Cines (166). , i APPENDIX K Comparison o f R e s u l t s from D u p l i c a t e Samples Kaganer " t " - p l o t C u m u l a t i v e Cumulative B.E.T. D u b i n i n I n t e r c e p t S u r f a c e S u r f a c e Sample Pore V o l . Pore Area Area m i s . ( S . T . P . ) / g . A r e a A r e a sq.m./g. sq.m./g. U n c o r r e c t e d C o r r e c t e d sq.m./g. sq.m./g. N i t r o g e n on Unbeaten P u l p - S o l v e n t Exchange D r i e d I s o t h e r m 1 150.3* 122.3* 193-0 49 33 214 262 201.4** 218.5** I s o t h e r m 2 159-1* 124.9* 193-4 54 34 236 261 210.6** 221.1** N i t r o g e n on P u l p Beaten 10 Minutes - S o l v e n t Exchange D r i e d I s o t h e r m 1 1 1 7 - 1 * 86.5* 151.9** 150.7** I s o t h e r m 2 120.6* 84.9* 153-5** 143.7** Argon on Unbeaten Pulp - S o l v e n t Exchange D r i e d I s o t h e r m 1 170.1 55 206 I s o t h e r m 2 177-4 59 221 * P a r a l l e l S i d e d F i s s u r e Model Assumed ** C y l i n d r i c a l Pore Model Assumed PORE ANALYSIS ON DUPLICATE SOLVENT EXCHANGE DRIED UNBEATEN PULP PARALLEL SIDED FISSURE MODEL ISOTHERM I. JL P . vads. wall separation pore area sum of pore area sq.rryg. pore volume mUSTPj/g. sum of pore vol. ml(S.T.P>g. & pore volume £ pore size 0. 900 199.400 0. 850 181.000 96. 48 3 7. 513 7.513 23. 38 3 2 3.383 0.663000 0. 800 164.100 69. 781 9. 230 16.743 20.777 44.159 1.145679 0. 75 0 ._. 149.200 55. 128 9. 981 26.724 17. 750 61 .909 1.588832 0. 700 138.400 45. 721 8. 294 35.018 12. 233 "74.142 1 .600437 0. 650 128.700 39.097 8.477 43.495 10. 691 84.833 1.907590 C. 600 120.800 34. 135 7. 551 51.045 8. 314 93.147 1.925174 0. 550 114.100 30. 248 6. 916 57.962 6. 748 99.895 1.952561 0. 500 105.500 27. 09 4 10. 327 68.288 9. 025 108.921 3.165624 0. 480 90.200 25. 164 22. 26 9 90.558 18. 077 126.997 17.892715 0. 460 81 .400 24. 184 12. 686 103.244 9. 897 136.895 10.433136 0. 440 76.900 • 23. 263 6. 050 109.294 4. 540 141.435 5.079371 0. 400 71.500 21. 99 3 6. 542 115. 836 4. 641 146.075 2.818710 0. 350 66.000 20. 248 6. 503 122.338 4. 247 150.323 2.304694 ISOTHERM 2. 0.900 207.300 0.850 0 .800 0.750 0 .700 0.650 0 .600 184.700 165.800 150.100 137.100 126.800 118.700 96.483 69.781 55.128 45.721 39.097 34.135 9.228 10.289 10.447 10.060 8 .908 7.605 9.228 19.516 29.964 40.024 48.932 56.536 28.720 23.160 18.579 14.837 11.235 8.374 28.720 51.880 70.459 85.296 96.530 104.904 0 .814337 1.277082 1 .663061 1.941166 2.004613 1.938977 0.550 112.000 30 .248 6.747 63.283 6. 583 111.487 1 .904794 0 .500 105.300 27.094 7.494 70.777 6. 550 118.037 2.297228 0.480 94.500 2 5.164 15.445 86.222 12.537 130.574 12 .409334 0 .460 83.000 24.184 16 .970 103. 192 13.239 143.813 13.956253 0.440 78.000 23 .263 6 .863 110.055 5. 150 148.963 5.762108 0 .400 71.700 21 .993 8.062 118.118 5. 720 154.683 3.473923 0.350 66 .000 20.248 6 .800 124.918 4.441 159.125 2.410062 PORE ANALYSIS ON DUPLICATE SOLVENT EXCHANGE DRIED UNBEATEN PULP CYLINDRICAL PORE MODEL ISOTHERM I. P« 0.900 C. 850 0.800 0.750 0.700 0.650 vads. mls(ST.P)/g 199.400 181.000 164.100 149.POO 138.400 128.700 diam of pore A 85.838 60.507 46.774 38.052 31.972 pore area sq.rryg. 9.206 12.312 14.373 12.708 13.864 sum of pore area sq.rryg. 9. 206 _21.518 35.891 48.599 62.463 pore volume mLSTP/g 25.492 24.030 21.687 15.599 14.298 sum of pore vol. A pore volume ml.(S.T.^gAP°re 25.492 49.522 71.209 86.808 101.106 0.758829 1.408004 2.085208 2.214420 2.795108 c. 600 120.800 27.462 12.97 8 7 5.441 11.497 112.603 2.943970 0. 550 114.100 23.961 12.436 87.877 9.612 122.215 3. 103894 0. 500 105.500 21.147 20.521 108.398 13.998 136.213 5.530292 0. 480 90.200 19.435 49.190 157.588 30.840 167.053 34.608826 0. 460 81.400 18.573 27.653 185.241 .16. 568 183.621 19.874390 0. 440 76.900 17.765 12. 132 197.373 6.953 190.573 8.884956 0. 400 71.500 16.657 11.163 208.536 5.998 196.571 4.184652 0. 350 66.000 15.145 9.915 218.451 4. 844 201.415 3.045551 ISOTHERM 2 0 .900 0.850 0 .800 0.750 0 .700 0.650 207.300 184.700 165.800 150.100 137 .100 85 .838 60 .507 46.774 38.052 11.308 13.713 15.017 15.471 11.308 25.021 40.038 55 .509 31.311 26.766 22.659 18.990 31.311 58.077 80.735 9 9 .725 0.932040 1.568292 2.178630 2.695895 0 .600 118.700 27.462 12 .955 82.964 11.476 126.156 2.938665 0.550 112.000 23 .961 11.968 94.932 9.250 135.406 2 .987172 0 .500 105 .300 21 .147 14.233 109. 165 9.709 145.115 3.835658 0.480 94.500 19.435 33 .825 142.990 21.207 166.322 23.798172 0 .460 83 .000 18.573 37.925 180.915 22.722 189.044 27.257278 0.440 7 8.000 17.765 14.213 195.128 8. 145 197.189 10 .408657 0 .400 0.350 71.700 66 .000 16.657 15.145 15.237 10.778 210.365 2 21.142 8. 187 5.265 205.376 210.642 5.711718 3 .310573 l. ro VJl O J l PORE ANALYSIS ON DULICATE SOLVENT EXCHANGE DRIED PULP BEATEN PARALLEL SIDED FISSURE MODEL ISOTHERM I. 10 MINUTES 0,900 vads. mts(SXR)/9 159.000 wall separation A pore area sq-rryg. sum of pore area sq.m./g. pore sum of I u m e volume pore vol. i=J- — 0 .850 0.800 0.750 0.700 0 .650 136.000 122.000 111.000 102.000 96.000 96.483 69 .781 55. 128 45.721 39.097 9.39 1 7.517 7.200 6.848 4.938 5 .644 9.391 16.908 24.108 30.956 35.894 41.538 29.228 16.921 12.804 10.100 6. 228 6.215 29, 46 , 58, 69, 75, 81 , 228 149 953 053 281 496 0.828750 0 .933056 1.146091 1 .321426 1.1 11295 1 .439112 0 .550 85 .500 30.248 4.422 4 5.9 60 4. 314 85 .810 1 .248314 0.500 80 .500 27.094 5 .631 51.59 1 4.921 90.732 1 .726151 0.480 76.000 25. 164 6. 166 57.757 5. 005 95.737 4.954384 0.460 66.000 24.184 14.967 72.724 11.676 107.413 12 .308504 0 .440 63.000 23.263 3.986 76.710 2. 991 110.404 3.346241 0.400 59.000 2 1.993 4.950 81.660 3. 512 113.916 2 .133071 0.350 55.000 2 0.24 8 4.811 86.471 3. 142 117.058 1 .705007 ISOTHERM 2. 0.900 160.000 0 .850 134.500 96 .483 10.412 10.412 32.405 32.405 0.918832 '0.800 118.200 69.781 8 .773 19.185 19.749 52.154 1.088985 0 .750 106 .500 55 .128 7.613 26.798 13.539 65.693 1.211926 0.700 97.900 45.721 6.414 33.212 9.459 75.152 1 .237582 0 .650 91 .000 39.097 5.757 38.969 7.261 82.413 1.295621 0.600 85 .200 34.135 5 .321 44.291 5.859 88.273 1 .356727 0 .550 80 .500 30.248 4.590 48.88 1 4.479 92.752 1.295913 0.500 76.500 27.094 4. 136 53.017 3.615 96.367 1.267979 0 .480 71.300 25.164 7.206 60.223 5.849 102.216 5.789632 0.460 62 .800 24.184 12 .586 72.809 9.819 112.035 10 .350 646 0 .440 59.800 23.263 3.985 76.794 2.990 115.025 3.345369 0.400 55.700 21 .993 5.119 81.913 3.632 118.657 2 .205873 0 .350 52 .700 20 .248 2 .957 84.870 1.931 120.588 1 .047867 PORE ANALYSIS ON PULICATE SOLVENT EXCHANGE DRIED PULP BEATEN 10 MINUTES CYLINDRICAL PORE MODEL ISOTHERM I. 0 .900 vods. mlslSXRVg 159.000 diam. of pore pore area sqm/o, sum of pore S U m of pore area volume pore vol. & P ° r e sq.rryg. mLSTP/g m ! ( S j i ^ &P o r e s l z e 0.850 136.000 85 .838 11.508 11.508 31.865 31 .865 0 .948537 0 .800 122.000 60.507 9.986 21.494 19.492 51.357 1.142076 0.750 111.000 46.774 10.306 31.800 15.550 66 .907 1 .495132 0.700 102.000 3 8.05 2 10.486 42.286 12.871 79.777 1.827189 0.650 96.000 31.972 7.883 50.169 8. 130 87 .907 1 .589287 0 .600 90.000 27.462 9 .696 59.864 8.589 96.497 2.199409 0.550 85.500 23.961 7.781 67.645 6.014 102.510 1 .942039 0 .500 80.500 21. 147 10.834 78.479 7. 390 109.901 2 .919578 0.480 76.000 19 .435 13.187 91.665 8. 267 118.168 9.277696 0.460 66.000 18.573 33.906 125.572 20.314 138.482 24.368973 0.440 63.000 17.765 8.027 133.599 4. 600 143.082 5 .878546 0.400 59.000 16.657 9 .06 3 142.662 4. 870 147.952 3.397292 0.3 50 55.000 15.145 7 .996 150.658 3. 907 151.859 2 .456254 ISOTHERM 2. 0.900 160.000 0 .850 134.500 85 .838 12 .759 12.759 35. 328 35.328 1.051638 0.800 118.200 60.507 11 .662 . 24.421 22. 762 58.091 1 .333710 0 .750 106.500 46.774 10.877 35.298 16. 411 74.502 1.577969 0.700 97.900 38.052 9.749 45.047 11. 967 86.469 1 .698815 0.650 91.000 31.972 9.268 54.315 9. 559 96.028 1.868598 0.600 85 .200 27.462 9.029 63.344 7 .999 104.026 2 .048231 0 .550 80 .500 23.961 8.076 71.420 6. 242 110.268 2.015640 0.500 76.500 21.147 7.520 78.940 5. 130 115.398 2 .026561 0 .480 71 .300 19.435 15 .561 94.501 9. 756 125.154 10.948153 0 .460 62 .800 18.573 28 .349 122.850 16. 985 142.139 20 .375061 0 .440 59 .800 17.765 8. 107 130.957 4. 646 146.785 5.937168 0.400 55.700 16.657 9 .666 140.623 5. 194 151.979 3 .623425 0 .350 52.700 15.145 3.062 143.686 1. 49 6 153.475 0.940693 I ro I 

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