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Gas absorption on wood pulp cellulose Orr, Ronald Gordon 1970

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i  GAS ADSORPTION ON WOOD PULP CELLULOSE by Ronald Gordon O r r B.A.Sc.  University  of B r i t i s h Columbia,  A Thesis Submitted In P a r t i a l F u l f i l m e n t The R e q u i r e m e n t s  F o r The D e g r e e  1963  Of  Of  Doctor of Philosopy In" The . D e p a r t m e n t 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  required  THE  standard.  UNIVERSITY OF B R I T I S H COLUMBIA  In  presenting  this  thesis  an a d v a n c e d  degree at  the  shall  I  Library  further  for  scholarly  by h i s of  agree  this  the  make  it  fulfilment  of  University  of  Columbia,  freely  that permission  for  It  financial  is  for  for extensive by  the  gain  Department Columbia  shall  not  the  requirements  reference copying of  I  agree  and  copying or  be a l l o w e d  for  that  study.  this  thesis  Head o f my D e p a r t m e n t  understood that  written permission.  The U n i v e r s i t y o f B r i t i s h V a n c o u v e r 8, C a n a d a  British  available  p u r p o s e s may be g r a n t e d  representatives. thesis  in p a r t i a l  or  publication  without  my  ABSTRACT  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 at 78 °K have been d e t e r m i n e d on samples o f s o l v e n t exchange d r i e d , f u l l y b l e a c h e d , k r a f t p u l p o f 1 w e s t e r n hemlock and The  s o l v e n t exchange d r y i n g sequence  used was  Douglas.fir.  water-methanol-  n-pentane w i t h the n-pentane removed at room t e m p e r a t u r e .  The  p u l p samples were i n two groups: one group was b e a t e n t o ' v a r i o u s l e v e l s on a P.P.I, m i l l and s o l v e n t exchange d r i e d  from  a water s w o l l e n s t a t e ; the second group was a i r d r i e d t o d i f f e r e n t m o i s t u r e c o n t e n t s and t h e n s o l v e n t exchange d r i e d . The presence o f 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 ) i n s o l v e n t exchange d r i e d c e l l u l o s e has been shown. was  s u g g e s t e d by the r e s u l t s o f H a r r i s , who  This f i n d i n g  noted that adsorbents  h a v i n g an average pore r a d i u s o f l e s s t h a n 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 o f 18 ft. The i n s o l v e n t exchange d r i e d c e l l u l o s e was  f i n d i n g of micropores 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 v e r y l a r g e volume o f pores at 18 & r a d i u s , and by the D u b i n i n p l o t t e c h n i q u e f o r t h e measurement o f micropore•volume. wood p u l p samples  Some s o l v e n t exchange d r i e d  i n d i c a t e d t h a t up t o 70 p e r c e n t o f t h e i r  pore volume was p r e s e n t as m i c r o p o r e s .  total  The presence of m i c r o -  pores w i t h the a s s o c i a t e d enhanced a d s o r p t i o n and  restricted  a d s o r p t i o n space c o m p l i c a t e s the a n a l y s i s o f i s o t h e r m s so t h a t the B. E. T. s u r f a c e a r e a and K e l v i n t y p e pore a n a l y s i s be c o n s i d e r e d r e l i a b l e .  can-not  i i i  An with  assuming  molecules  some p u l p models  to  values  trends  that  the Dubinin  pore  t h e model assumed t o d e s c r i b e  gas a d s o r p t i o n  f o rsolvent  a n a l y s i s , was f o u n d The imately ation  sided  materials  data  volume  dried pulp reliable  (cylindrical fissure  of pores  samples,  pore  o f pores  found  exchange  by o t h e r  t h e most  common p o r e  separ-  dried  workers has  finding i s substantiated does  sheets.  o f approx-  25'ft w a l l  model) o r  and S c a l l a n which  near  t h e B.E.T.  on a i r d r i e d p a p e r  model) i n s o l v e n t  This  o f Stone  are of doubtful  volume  which have been  by t h e  not indicate sizes  found by  adsorption. P. F. I . m i l l  the  sensitive  the physical structure.of the  of the large  shown t o be d o u b t f u l .  accessibility  gas  exchange  existence  (parallel  large  analysis  shown t o be v e r y  techniques  t o be q u i t e  18'ftr a d i u s  cellulosic been  pore  to postulate  fibre. While  validity  n o t be u s e d  The K e l v i n t y p e  a n a l y s i s have been  i s useful f o r  f o rcorrelations of  but should  o f s p e c i f i e d dimensions.  associated  o f adsorbed  gas a d s o r p t i o n  o r f o r use asa parameter  and paper p r o p e r t i e s  wood p u l p  a  f o rthe p h y s i c a l properties  l e dt o the conclusion  indicating  and  investigation into the effects of errors  surface  slightly  area  micropore  slightly,  t o l a r g e r pore  volume'of pores volume  volume w i t h  beating  to shift  was f o u n d  the pore  size  t o lower  distribution  s i z e s and t o s u b s t a n t i a l l y lower t h e  a t t h e most analysis  beating.  o f the pulp  common p o r e  also  These  size.  The  indicated lowering  Dubinin o f micropore  r e s u l t s l e dt o t h e c o n c l u s i o n  that  beating  a f f e c t e d the  structural  elements Partial  exchange two  strongly  preted  of  to  on  the  drying  the  pore  area  of  the  volume  the  Stone  structure of  a  structure similar  have  a  flat  those  found  by  found  to  the  be  distribution  the  density  E.  increased.  sided  Comparisons  exchange  analytical  dried  wood  which  of  the  surface  methods were T.  techniques  d r i e d wood p u l p  equation,  w e r e made f r o m to  as  is  area.  however,  were  additional The  significantly  was  and  the  pulp  physical tests.  determined found  increased  length  inter-  the  surface  larger  trends  than  were  same.  were  area  estimates  B.  subjected  sheets  easily  to montmorillonite,  "t"-plot  exchange  these  Handsheets were  and  solvent  by  nearly  plate structure.  Kaganer  determined  cellulose.  indicated solvent  have  areas  solvent  pore, s i z e s .  shapes  obtaining  to  by  Scallan parallel  of  area  shift  surface  and  of  methods  breaking  the  prior  basis  the  Sheet  to  handsheets  the  to  bonded  lower  in  measured.  d r y i n g were  applied  The  and  pulp  even  and  The  these  to  size  fibre  e f f e c t s of .beating  isotherm  sheets  the  pulp  The  between  known t o  the  smallest  of  found  smaller  model  may  the  magnitude  fissure  pulp  of  d r y i n g was  orders  structure of  as  burst.  to  and  the  bonded  increase  bonded Tear  The  area  with  samples surface areas  the  these  areas  of  estimated.  level  increasedjSO  f a c t o r decreased  and  as  of did the  beating. the bonded  VI  GAS  ADSORPTION ON WOOD PULP CELLULOSE  I INTRODUCTION  Page 1  A.  Cellulose  B.  C e l l u l o s e S u r f a c e Area  C.  P r e s e n t a t i o n of the Problem  '  4 5  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 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 o f a Wood P u l p F i b r e  8  C.  Sample Requirements f o r Gas A d s o r p t i o n  9  D.  Freeze Drying  9  E.  S o l v e n t Exchange D r y i n g  11  F. . Gas A d s o 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 G. I n t e r p r e t a t i o n of Gas A d s o r p t i o n R e s u l t s i n Terms of the P a r a l l e l S i d e d 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  18  H.  D i s t r i b u t i o n o f Water ' i n the C e l l W a l l  49  I.  E f f e c t of B e a t i n g on S u r f a c e Area S o l v e n t Exchange D r i e d P u l p s  49  J.  The I n f l u e n c e of C o m p o s i t i o n and S u r f a c e Area  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 Materials  I I I INTER FIBRE BONDING AND  on  of  Porosity  MEASUREMENT OF BONDED AREA  48  51 53 59  IV BACKGROUND THEORY A.  The  B.E.T. E q u a t i o n and S u r f a c e Area  B.  Most Common Pore S i z e and Molecule Size  62  Adsorbate 66  vii C.  D e t e r m i n i n g P o r e S i z e by t h e K e l v i n Equation  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  Page 68 75  1.  Macropores  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  76  3.  Micropores  78  .  75  E.  The S p e c i a l P r o b l e m o f M i c r o p o r e s  80  F.  The D u b i n i n T h e o r y o f A d s o r p t i o n on Microporous Solids  83  G.  The K a g a n e r M e t h o d f o r D e t e r m i n a t i o n o f the Surface Area  87  H.  The Work o f H a r r i s a n d S i n g  89  I.  " t " P l o t Method f o r A n a l y s i s o f Adsorption Isotherms  92  V APPARATUS j MATERIALS AND EXPERIMENTAL PROCEDURES A.  Introduction-  97  B.  D e s c r i p t i o n o f M a t e r i a l s Used  97  C.  Continuous Flow A d s o r p t i o n Apparatus  97  D.  The V o l u m e t r i c A p p a r a t u s  103  E.  Solvent E x t r a c t i o n Apparatus  106  F.  Beating of Pulp  108  G.  Paper T e s t i n g  108  H.  Experiments Performed  109  .  V I EXPERIMENTAL RESULTS AND DISCUSSION A. , 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 n d O x y g e n B. B.E.T. A n a l y s i s o f I s o t h e r m s . C. Pore A n a l y s i s 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 o m A c c e s s i b i l i t y a n d Gas A d s o r p t i o n Data  111 128 138  164  VI11  Page 168a  E.  D u b i n i n Pore A n a l y s i s  F.  Kaganer S u r f a c e Area D e t e r m i n a t i o n  182  G.  Cellulose " t " Plots  182  H.  Comparison o f S u r f a c e Areas by t h e V a r i o u s Techniques  I.  Calculated 192  P h y s i c a l T e s t i n g o f t h e Handsheets o f the E x p e r i m e n t a l P u l p s  VII  192a  CONCLUSIONS  201  NOMENCLATURE  20 3  LITERATURE CITED  205  APPENDIX A E x p e r i m e n t a l Isotherms  214  APPENDIX B S u r f a c e Area o f Handsheets ( Dynamic A d s o r p t i o n Apparatus) 218 APPENDIX C 1.  N i t r o g e n A d s o r p t i o n Data o f H u n t , B l a i n e and Rowen .  219  2.  I s o t h e r m Data o f H a s e l t o n  220  3.  I s o t h e r m Data o f Merchant  221  4.  I s o t h e r m Data o f Sommers  223  5.  I s o t h e r m Data on Hollow F i l a m e n t Rayon S u p p l i e d by S c a l l a n  224  6.  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  225  APPENDIX D 1.  Pore A n a l y s i s U s i n g S t a n d a r d i z e d N i t r o g e n Isotherms  226  2.  Pore A n a l y s i s U s i n g E x p e r i m e n t a l of N i t r o g e n Isotherms  228  3.  Values  Pore A n a l y s i s U s i n g S t a n d a r d i z e d Argon Isotherms  230  k.  Pore A n a l y s i s U s i n g E x p e r i m e n t a l V a l u e s o f .Argon Isotherms  5.  Pore Volumes E x p r e s s e d as B u l k L i q u i d Volumes  6.  Reduced C u m u l a t i v e Pore Volumes  APPENDIX E Grades and S u p p l i e r s o f C h e m i c a l s Used APPENDIX F 1.  Argon A d s o r p t i o n on Nonporous Adsorbent  2.  N i t r o g e n S t a n d a r d Isotherms  APPENDIX G 1.  C o r r e c t e d D u b i n i n Data  2.  B.E'.T. and D u b i n i n ' ( o r Kaganer)  Data  APPENDIX H 1.  " t " P l o t . Data  2.  Comparison o f " t " P l o t V a l u e s U s i n g t h e D i f f e r e n t S t a n d a r d Isotherms  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 i n V o l u m e t r i c Apparatus 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 t o 78°K  Properties  APPENDIX K Comparison o f R e s u l t s from D u p l i c a t e Samples  X  L I S T OF TABLES Page 1.  Effect  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.  Effect  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.  C o m p a r i s o n o f S u r f a c e A r e a s D e t e r m i n e d By W a t e r and N i t r o g e n A d s o r p t i o n  20  V a r i a t i o n o f Surface Area o f C e l l u l o s e B e a t e r Treatment  23  4. 5.  with  E f f e c t o f A d s o r b e d Water on t h e A r e 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  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 E x c h a n g e D r i e d F i b r e s - B.E.T. A r e a s a n d P o r e S i z e Distributions  31  B. E. T. S u r f a c e A r e a s o f S a m p l e s 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 I s o t h e r m s D e t e r m i n e d by Sommers  34  9.  B. E. T. A r e a s a n d P o r e V o l u m e s 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  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 ( S t o n e a n d S c a l l a n )  44  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 a n d R e s w e l l i n g i n W a t e r  47  P r o p e r t i e s of Macromolecules Scallan  54  6.  7.  10. 11. 12. 13.  U s e d by S t o n e a n d  A p p r o x i m a t e 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 s on Various Materials  65  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 B e n z e n e A t 20 °C on C a r b o n B l a c k a n d A c t i v e C a r b o n s  80  15.  B. E. T. M o n o l a y e r V o l u m e s a n d A r e a s 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  14.  D e p e n d e n c e 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.  R a n g e s o f B. E. T. A r e a s on B e a t e n S a m p l e s  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 C o n t e n t  137  19.  E f f e c t o f I n i t i a l D a t a P o i n t on C u m u l a t i v e Volume and C u m u l a t i v e Pore A r e a  141  Pore  xi Page 20.  Pore S i z e at Steepest Descent on D e s o r p t i o n Isotherms  146  21.  M o l e c u l a r Volumes of Adsorbates  149  22.  Pore Volumes o f D i f f e r e n t S i z e d Pores  156  23.  Comparison o f V a r i o u s C a l c u l a t e d Volumes  158  24.  Median Pore S i z e as Determined By E q u a t i o n 1.  25.  Comparison Between B. E. T. S u r f a c e Areas and Pore Areas Area o f Pores Above 25-2 ft W a l l S e p a r a t i o n o r 21.2 ft Diameter ( N i t r o g e n Isotherm)  26. 2728.  I n t e r c e p t Values f o r C o r r e c t e d and U n c o r r e c t e d D u b i n i n P l o t s With M o i s t u r e Content as V a r i a b l e  l6l 163 170 176  The E f f e c t of B e a t i n g on C o r r e c t e d D u b i n i n Analysis  177  29.  Uncorrected Dubinin P l o t I n t e r c e p t s  178  30.  S u r f a c e Areas as Determined By " t " - P l o t Technique  188  31. " Comparison o f S u r f a c e Areas C a l c u l a t e d by the V a r i o u s Techniques  191  32.  P h y s i c a l Test R e s u l t s on E x p e r i m e n t a l Pulps  193  33-  E s t i m a t e d Bonded Areas of Handsheets  196  xii L I S T OP  FIGURES Page  1.  Formulae  2.  Model  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 Hydrocarbons 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 B e t w e e n F i b r e A r e a and Liquid  16  5.  2  of C e l l u l o s e  10  o f S t o n e and S c a l l a n  Residual  D a t a o f H u n t , B l a i n e and Rowen: N i t r o g e n on C o t t o n  Adsorption 22  Cellulose  6.  N i t r o g e n Isotherm Data o f H a s e l t o n  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 E x c h a n g e D r y i n g on N i t r o g e n I s o t h e r m s 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 E x c h a n g e D r y i n g on Nitrogen Isotherms  8.  9.  26  27 28  I n f l u e n c e o f B e a t i n g on 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 by T h o d e , Swanson and B e c h e r  30  10.  Sommers I s o t h e r m D a t a  35  11.  Change o f P o r e Volume D u r i n g  12.  The  D i s t r i b u t i o n of Water i n Pulp F i b r e s  50  13.  The  Accessibility  56  14.  R e l a t i v e S i z e s o f Most Common P o r e S i z e Adsorbed N i t r o g e n Molecules  15. 16. 17. 18. 19.  46  Drying  D a t a o f S t o n e and S c a l l a n and  67  E f f e c t o f C h a n g i n g P h y s i c a l P a r a m e t e r s on P o r e 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  E f f e c t o f C h a n g i n g P h y s i c a l P a r a m e t e r s on P o r e Volume D i s t r i b u t i o n ( P a r a l l e l Sided F i s s u r e Model)  72  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 P o r e W a l l s on P o r e Volume D i s t r i b u t i o n  74  C o m p a r i s o n o f A v e r a g e P o r e 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  A p p a r e n t Volume o f M i c r o p o r o u s T i t a n i a o f T e m p e r a t u r e and A d s o r b a t e  93  as  Function  xiii 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 Continuous  22.  Schematic Diagram o f Continuous  23.  Sample Tubes f o r C o n t i n u o u s  Plow Equipment  Flow  98 99  Flow Equipment Adsorption  Apparatus  101  24.  Volumetric  25.  Solvent E x t r a c t i o n Apparatus  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 E x c h a n g e D r i e d Unbeaten P u l p Samples 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 E x c h a n g e D r i e d P u l p S a m p l e s B e a t e n f o r 10 M i n u t e s i n P.. P. I . M i l l  27.  Adsorption  Apparatus  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 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 , A r g o n a n d O x y g e n a t 78 on 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  30.  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 n d O x y g e n a t 78 °K on S o l v e n t E x c h a n g e D r i e d P u l p B e a t e n .1 M i n .  31. 32. 3334. 3536. 37. 38.  1  2  113  °K  I s o t h e r m s o f N i t r o g e n a n d A r g o n a t 78 °K on S o l v e n t Exchange D r i e d Pulp Beaten 5 M i n . I s o t h e r m s o f N i t r o g e n a n d A r g o n a t 78 °K on S o l v e n t E x c h a n g e D r i e d P u l p B e a t e n 10 M i n .  Isotherms Contained  1  Exchange  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 n d O x y g e n a t 78 °K on S o l v e n t E x c h a n g e D r i e d P u l p B e a t e n 3 M i n .  I s o t h e r m s on S o l v e n t E x c h a n g e D r i e d P r e v i o u s l y Vacuum D r i e d  ?  1 0  H° 1 1  7  1 1  °  1 1  9  Sheets 1^0  on S o l v e n t E x c h a n g e D r i e d S h e e t s W h i c h 5-3 P e r c e n t M o i s t u r e  121  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 C o n t e n t P r i o r t o S o l v e n t Exchange D r y i n g as P a r a m e t e r  122  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 E x c h a n g e 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  Dried  A d s o r p t i o n Isotherms o f N i t r o g e n , Argon and O x y g e n on Vacuum D r i e d U n b e a t e n P u l p S h e e t s  124  XIV  Page 39.  Isotherms  40.  B. E. T. P l o t s f o r N i t r o g e n , A r g o n and S o l v e n t Exchange D r i e d Unbeaten Pulp  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 D r i e d B. E. T. S u r f a c e A r e a  42. 43.  44.  45.  46. 47. 48.  49.  50.  51.  52. 53.  126  on M o n t m o r i l l o n i t e Oxygen  on  129  Exchange 133  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 P r i o r t o S o l v e n t Exchange D r y i n g  Content 136  C u m u l a t i v e P o r e Volume D i s t r i b u t i o n s f o r U n b e a t e n S o l v e n t E x c h a n g e D r i e d P u l p U s i n g N i t r o g e n and Argon Desorption Isotherms  139  Cumulative Pore Area of Unbeaten S o l v e n t D r i e d P u l p as D e t e r m i n e d By N i t r o g e n and Desorption Isotherms  140  Exchange Argon  D i f f e r e n t i a l P o r e 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 Pulp U s i n g N i t r o g e n and A r g o n D e s o r p t i o n I s o t h e r m s R e d u c e d C u m u l a t i v e P o r e Volume D i s t r i b u t i o n s A Number o f C e l l u l o s i c M a t e r i a l s C u m u l a t i v e P o r e Volume E x p r e s s e d A d s o r b a t e i n B u l k L i q u i d Form  As mis  144 for 145  of 148  C u m u l a t i v e P o r e 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 Adsorbate Vacuum D r i e d - S o l v e n t E x c h a n g e D r i e d Sample  150  D i f f e r e n t i a l P o r e 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 A r g o n I s o t h e r m s  151  C u m u l a t i v e P o r e Volume D i s t r i b u t i o n w i t h D e g r e e o f B e a t i n g as P a r a m e t e r C a l c u l a t e d from N i t r o g e n Desorption Isotherms  153  C u m u l a t i v e P o r e Volume D i s t r i b u t i o n s o f 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 B e a t e n 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 Isotherms  154  E f f e c t o f W a t e r C o n t e n t on R e d u c e d P o r e Volume D i s t r i b u t i o n  159  Cumulative  R e d u c e d C u m u l a t i v e P o r e V o l u m e s as D e t e r m i n e d 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 P o r e Volume as D e t e r m i n e d 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.  Effect  o f M o d e l On  Corrected Dubinin  by  Plot  171  XV  56.  Sensitivity Separation  to Area of Pores U n b e a t e n Sample  Page 26 ft W a l l . 173  57.  Corrected Dubinin as P a r a m e t e r  58.  Dubinin P l o t s of Nitrogen A d s o r p t i o n Isotherms (Uncorrected) 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 P a r a m e t e r  59.  60. 61,.  Plots with Moisture  Content  174  175  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 and O x y g e n 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 E x c h a n g e D r i e d Unbeaten Pulp ' Dubinin P l o t s of Nitrogen A d s o r p t i o n Isotherms w i t h m i n u t e s P. F. I . M i l l B e a t i n g as P a r a m e t e r "t"-Plots Different  of S o l v e n t Exchange D r i e d P u l p u s i n g "Standard" Isotherms  62.  " t " - P l o t s w i t h Time B e a t e n as P a r a m e t e r  63.  " t " - P l o t s w i t h Moisture Content P r i o r to E x c h a n g e D r y i n g as P a r a m e t e r  64.  " t " - P l o t s 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 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 M o n o l a y e r s  „ i a o  1  °  1  . i y 4  1 8 6  Solvent  65.  P h y s i c a l P r o p e r t i e s o f H a n d s h e e t s as a o f Time o f B e a t i n g o f P u l p  Function  66.  P h y s i c a l P r o p e r t i e s o f H a n d s h e e t s as a o f t h e B. E. T. S u r f a c e A r e a  Function  67.  Dependence o f P h y s i c a l P r o p e r t i e s o f on E s t i m a t e d B o n d e d 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 H a n d s h e e t s as F u n c t i o n o f the I n v e r s e o f the Apparent Bonded A r e a  Handsheets  187 ^  194 195 197 198  xvi  ACKNOWLEDGMENT  Thanks a r e e x t e n d e d t o t h e f a c u l t y and s t a f f o f the  Chemical E n g i n e e r i n g Department, U n i v e r s i t y  Columbia.  The a u t h o r a l s o w i s h e s t o t h a n k t h e F a c u l t y o f  Forestry, University of British  C o l u m b i a , 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 t h e B r i t i s h of  Technology Drs.  Institute  of British  f o r t h e k i n d use o f t h e i r  Columbia  Institute  facilities.  Stone and S c a l l a n o f P u l p and Paper  Research  o f Canada and D r . M. R. H a r r i s o f t h e 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 a n d d a t a . A s p e c i a l thank you i s extended t o t h e author's p a r e n t s , Mr. a n d M r s . G o r d o n H. O r r , a n d t h e a u t h o r ' s w i f e , ' Charleen, f o r t h e i r kind assistance i n preparation of the manuscript. The his  a u t h o r i s i n d e b t e d t o D r . R. M. R. B r a n i o n f o r  d i r e c t i o n and s u p p o r t and i s g r a t e f u l  for the financial  a s s i s t a n c e e x t e n d e d by t h e N a t i o n a l R e s e a r c h  Council.  -  1  -  I - INTRODUCTION Cellulose,  t h e m a i n component o f wood and  is  t h e most a b u n d a n t o r g a n i c raw  is  one  The  o f t h e few  unique  intense  study  about t h i s  material available  fibres,  t o man,  and  resources that i s constantly being replenished.  c h e m i c a l and  a wide v a r i e t y  plant  p h y s i c a l nature  of uses.  Despite remarkable  of c e l l u l o s e ,  c o m p l e x and  of c e l l u l o s e  l e d to  a d v a n c e s due  t h e r e r e m a i n s much t o be  interesting  has  to  the  learned  material.  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 a r e t r a n s p o r t e d and  t r e a t e d i n an a q u e o u s medium, t h u s  behavior of c e l l u l o s e  i n water  i s one  o f t h e most  the  important'  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 -  Cellulose Cellulose  i s a l i n e a r p o l y m e r o f D.-glucose  u n i t s , each u n i t j o i n e d Figure  1 shows t h e  to the next  c h e m i c a l and  of the c e l l u l o s e molecule o r D.P.,  ticularly  meric  a 1-4g  -glycosidic linkage.  configurational  (1,2).  The  formulae  degree of p o l y m e r i z a t i o n ,  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  ten thousand,  primary  by  anhydride  (molecular weight  important  and  unit.  two  o f up  t o 1,620,000) ( 1 ) .  to the p r o p e r t i e s of c e l l u l o s e  secondary  T h e s e may  h y d r o x y l groups present  participate  in inter-  to  Par-  are the  one  on e a c h mono-  or i n t r a -  molecular  hydrogen bonds. Wood p u l p  contains considerable quantities  h e m i c e l l u l o s e , t h e amount p r e s e n t v a r y i n g f r o m of the h o l o c e l l u l o s e virtually  i n an u n b l e a c h e d  none i n an a l p h a c e l l u l o s e  of  a b o u t 22  percent  aspen semichemical d i s s o l v i n g pulp  (1).  pulp  to  _ 2 CHEMICAL  DIAGRAM  H  H  • H  H  1 I I  I  FIGURE - L FORMULAE OF CELLULOSE  -3Whereas units,  cellulose  almost  entirely  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  pentose  units.  A.very  xylose  with  ciable  amounts.  the  i s comprised  anhydro'-mannose  anhydro  D.  Besides  forms  Hemicelluloses average  common m o n o m e r i c  other  unit  frequently being  these,  of glucose,  there  may  of  T h e s e p o l y s a c c h a r i d e s may  hexose and  i s anhydropresent  i n appre-  be s m a l l .amounts o f  galactose, arabinose,  also invariably contain uronic acid  P. o f i s o l a t e d  anhydro-glucose  and rhamnose.  units.  hemicelluloses i s usually be c o - p o l y m e r s  The  about  150.  and a r e sometimes  branched. In arranged from  parallel  the less  crystalline infared  t o each  ordered  spectral  amorphous  fibres  which  i n t u r n make  fibre  (4).  these  sketch  like  composed  of strings,  fibril"  i s s t i l l  by x - r a y methods  form  ordered  analysis, such  as  the exact  micro-  fibrillar  o f Heyn  (7,8).  fibre  as b e i n g  made  strings.in  "elementary from  debate.  of this  up o f  turn  rope-  made  itself.  fibres are  fibrils".  the x-ray  The s i z e  a s u b j e c t o f much  strings  a p p r o p r i a t e , i fg r o s s l y  (6) p o s t u l a t e d t h a t  support  structure  microscopically visible  and these  crystalline  h a s r e c e i v e d some data  varying  upon,'electron  chains light  are usually  e t c , down t o t h e p o l y m e r m o l e c u l e  and M u h l e t h a l e r  up o f 35 ft t h i c k  microscopy  linear  of order  Although  not agreed  of the cellulose  of smaller strings,  postulate  (3)  chains  to the highly  :  (5) d r e w a v e r y  simplified,  made  regions  up t h e l a r g e r  Sommers  Frey-Wyssling  the degree  or by- chemical  i s s t i l l  has shown t h a t  polymer  c a n be d e t e c t e d  hydrolysis.  scopy  up  other,  analysis,  or acid  cellulose  fibres  the cellulose  regions which  deuteration of  wood p u l p ,  and  This electron  "elementary  The importance sorption,  wall  or the paper  i s present  the extent,  a wood p u l p structure,  cellulose  reactivity,  location  fibre  when  it.  materials,  optical properties  o f wood  pulp  the microscopically  surface  the fibre  internal  to the  cell  i s i n a swollen  and a v a i l a b i l i t y  state.  of the surface  i s a function of i t s microscopic  the porous  fundamental  p h y s i c a l ad-  The s u r f a c e  regions,  and t h a t  only  i s of  p h y s i c a l and c h e m i c a l  made- f r o m  two g e n e r a l  external surface  which  Since  pulp  of the chemical  a n d many o f t h e o t h e r  be d i v i d e d i n t o  visible  o f wood  r e t e n t i o n o f d y e s t u f f s and s i z i n g  the pulp  may  area  i n studies  properties of  surface  s t r u c t u r e o f wood p u l p  i s an  and  of  molecular  important  parameter.  ..  B - Cellulose.Surface The considerably For  apparent depending  e x a m p l e , wood  exhibit  specific  microscopically similar state 200  fibres  exhibit  s q . m.  area  lower turn roots  when  areas  solvent  nitrogen  i n surface  of cellulose and source  cellulose o f 0.4  (9) o r by n i t r o g e n  adsorption  fibres t o 1.0  The a p p a r e n t  crystalline  area  lower  than  cellulose  surface  o f t h e two p l a n t  cotton  areas  species  than  vanda  fibres.  whereas swollen  o f up t o surface  on t h e s o u r c e being  of the  somewhat  f r o m wood, w h i c h i n  the cellulose  suavis  water  measured  a water  specific  fibres  fibres  of the  (10,11),  areas  f i b r e s - i s a l s o dependent  varies  d r i e d from  d r i e d from  surface  fibres  sq.m./g.  adsorption  exchange  (5,12,13).  t h e more  gigantum (14).  area  on t h e h i s t o r y  and c o t t o n  p e r gm.  h a v e much  surface  surface  of cellulose  cellulose;  Area  and  from  aerial  philodendron  -5-  The cellulose its  t h e o r e t i c a l maximum s p e c i f i c  assuming t h a t each m o l e c u l a r  neighbours  and I s a b l e t o adsorb  meter adsorbate  surface area of  chain i s separated  from  a monolayer o f a s m a l l  dia-  may be e s t i m a t e d by one o f two m e t h o d s : m e a s u r e -  ments on m o l e c u l a r m o d e l s  ( t h e 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 a b o u t 1600 s q . m . / g m . ) ( 1 4 ) m e a s u r e m e n t o f t h e area of spreading of c e l l u l o s e which it  a s a m o n o l a y e r on w a t e r  y i e l d s a s u r f a c e a r e a o f a b o u t 1200  s h o u l d be k e p t  cannot  (15),  sq.m./gm.However  i n m i n d 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  be p r e c i s e l y  defined.  C - P r e s e n t a t i o n o f the Problem Initially relationships of  paper.  of  measuring  t h i s p r o j e c t was c o n c e i v e d as a s t u d y  among t h e b o n d e d a r e a a n d t h e p h y s i c a l p r o p e r t i e s  Gas a d s o r p t i o n t e c h n i q u e s w e r e p r o p o s e d t h e bonded a r e a .  These t e c h n i q u e s  a p p l i e d w i t h considerable success of  m a t e r i a l s such  as s i l i c a  (13), M e r c h a n t  a s t h e means  have been  t o s t u d i e s on t h e s t r u c t u r e  g e l s , porous carbons,  various heterogeneous c a t a l y t i c m a t e r i a l s . Haselton  of the  (12), Sommers  have u s e d gas . a d s o r p t i o n t e c h n i q u e s  c l a y s and  S t o n e a n d S c a l l a n (16),  (5). a n d o t h e r s ' (17-19)  t o study  c e l l u l o s i c materials."  S o l v e n t e x c h a n g e d r y i n g i s one o f t h e m e t h o d s t h a t was p r o p o s e d pulp  to yield  an e s t i m a t e o f t h e u n b o n d e d a r e a o f t h e  f i b r e s p r i o r t o sheet  formation.  However, s o l v e n t exchange  d r y i n g c a n r e t a i n much o f t h e i n t e r n a l a r e a fibre. fibre will  This i n t e r n a l a r e a , w h i l e unable b o n d e d a r e a , c a n be t h e s i t e  of the  to contribute to inter-  of intrafibre  contribute to the strength of the fibre  strength of the sheet.  (pore area)  bonds  which  and hence t o t h e  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  -6study the  of the effects  wood p u l p  when  o f changes  the pulp  A literature in  which  pores as  he p r e s e n t e d  which  pores  i nreality  revealed a paper  on t i t a n i a s  had r a d i i  than  18 ft. G a s a d s o r p t i o n r e s u l t s  cellulosic  equation  i s i n fact  Harris indicated  appear.  These  results  exchange  dried  wood p u l p  18 ft r a d i u s  and Sing  micropores,  ( i . e . B.E.T.,  Thus,  as t h e p r e s e n c e  analytical  As this  work i.  a result  large  pores  would  as i m p l y i n g t h a t  definition,  (20) i n d i c a t e d  an  radius  also solvent  of less  section  t h a t when  than  I V - D - 3) • adsorbent  gas a d s o r p t i o n a n a l y t i c a l  tech-  analysis) arenot reliable. i n s o l v e n t exchange  thereliability also suspect  o f these  dried  dried  o f t h e gas a d s o r p t i o n  f o r surface area  findings  the final  measurements  objectives of  were:  t o determine micropores  i i .  by D u b i n i n  techniques.was  less  a very  contained pores  o f micropores  was s u s p e c t e d ,  implies  of radii  that  smaller sized  pore  appear  a t 18 ft r a d i u s , . t h e p o r e  cellulose  Kelvin  This  on s o l v e n t exchange  interpreted  the usual  niques  wood p u l p  found  many  were  (micropores  A book by Gregg contains  f o r pores  m a t e r i a l s (5,12,13,16) i n d i c a t e d  o f pores  which  i snot v a l i d  indicating that  18 ft w o u l d  o f 18 ft r a d i u s o n a d e s o r p t i o n i s o t h e r m .  theKelvin  at  than  treatments.  b y H a r r i s (1^9)  and aluminas  of less  that  volume  structures of  was s u b j e c t e d t o v a r i o u s  search data  i nthe internal  to- s t u d y  i f s o l v e n t exchange  and i f so attempt  the r e l i a b i l i t y  wood p u l p  to.estimate  their  o f t h e gas a d s o r p t i o n  techniques  f o r s o l v e n t exchange  dried  sheets.  pulp  dried  dried  wood p u l p  contains  volume, analytical and a i r  iii.  t o determine  6 a -  i f the l a r g e volume o f pores  of 18 A  r a d i u s i n s o l v e n t exchange d r i e d c e l l u l o s i c m a t e r i a l s i s a r e a l volume or an a r t i f a c t  o f the a n a l y t i c a l  technique iv.  t o determine  the changes i n i n t e r n a l s t r u c t u r e with  b e a t i n g o f the pulp^ and d r y i n g o f pulp v. t o determine  handsheets.  a model which best s u i t s the changes i n  the wood pulp s t r u c t u r e and area when i t i s converted into  p'aper.  -7-  II A  - The  E f f e c t Of  Cellulose  Surface  Fibres  Urquhart cotton found is  that  the  than  has  spruce  amount  the  water  Merchant pulp  spersion  i n water  solvent  and  found  an  pulp  sheets  over  exchange  Chase  Hu  has  been  by  generally  bonding  and  using  the  during  atmospheres  exact  be  into nature  generally  which  thought  can act  contact  this to  pentoxide  area  dye  by  (16,  by  percent.  to  bring  to  thus  allowing  is s t i l l  inter-and  pressures the  bonding  debated  intra-fibre  to  but  of  strength  hydrogen-  the  surface  paper  tensile  loss  of  also Drying  make  lower  of  Thode,  drying.  This  elements  by  technique  irreversible  the  redi-  60  elements  large  a  determined  of  on  bleached  available for interfibre  create  bleached  as  with  23-25).  Stone  irreversibly  adsorption  decrease  dried  exchange-  fully  area,  once  of  followed  adsorption  area  a  of He  fibre.  solvent  drying  a r e s u l t of  bonding be  by  drying  fibre  decreased  (26-28) s h o w e d how  drying  close of  sites  In  process.  dried  r e s u l t i n a paper  to  that  r e d i s p e r s i o n i n water  numerous w o r k e r s  number o f  a  surface  surface  surface  shown t o  and  specific  by  by  a never  between h y d r o x y l - c o n t a i n i n g  water  fibres  the  a  followed  Campbell  200  by  that  nitrogen  accepted  adsorbed  are  phosphorous  out  irreversible  measured  found  lowered  (23)  fibres  as  techniques  irreversible  strength  of  water  porosity  (22)  S t r u c t u r a l Changes  pointed  5  i s an  adsorbed  the  adsorption  sulphite  lower  of  on  Drying  i n 1929  sulphite tracheids  drying.  is  During  (21),  shown t h a t  nitrogen  of  Tension  c e l l u l o s e from water  less  (16)  - P R E V I O U S WORK  fibres  which  bonding. tension of  the  forces order  cellulose occur.  The  i t is  hydrogen  bonding  of  -8with The  some  fibrillar  compacting  fundamental face  and p o s s i b l y  pressure  laws  when w a t e r  webs w i t h surface  tension that  of  strength  of  the drying  25 p e r c e n t  - Stone  the  pulp  bonding  and then range  They  the development content  u p t o 20-25 p e r c e n t , strength reach  the  essentially  a maximum  show a d e c l i n e  at higher  o f 20-25 p e r c e n t  solids,  The s t r e n g t h  Robertson  between t h e  As t h e s o l i d s  forces  factor.  fibre  effects.  underlying  increasing  These  t o dryness.  a t 20-  solids interfibre  then  (3*0 came t o  and S c a l l a n Model  f o r the Structure  Stone  ( 1 6 , 35) h a v e  and S c a l l a n  o f a wood p u l p  adsorption  data  fibre.  were  increases  essentially  within the c e l l  axis.  These  sheets  These  are laterally  may  Fibre  a model f o r  i n forming  microfibrils  are arranged  sheets  Pulp  Electron micrographs  that  wall  o f a Wood  proposed  instrumental  They p o s t u l a t e d  sheets. fibre  by means o f g l a s s  a separation  increases  with  on t h e d e v e l o p -  conclusions.  cross-section  the  mechanism  forces.  In this  interpretation  form  together  solids  structure  nitrogen  agents,  suspension  becomes t h e m a j o r  same  achieved,  e f f e c t s and i n t e r f i b r e  tension  continuously  3  This  Swanson and Jones  studies  i n p a p e r webs i s as f o l l o w s .  contents. bonding  bonding  the general  are held  surface  the  notably  (33) i n t h e i r  o f wet s h e e t s  and without  concluded  by  and G a l l a y  of strength  fibres  by o t h e r s  plates.  inter-  and Barkas (32). Lyne  ment  (29) t o t h e v a p o u r - l i q u i d  between two p a r a l l e l  phenomena has been d i s c u s s e d (30-3D  entanglement.  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  of c a p i l l a r i t y i s held  some m o l e c u l a r  of  and  their  new  rectangular  associated  to  c o n c e n t r i c a l l y around  aggregate  into thicker  sheets  -9or  lamellae,  extent a  the average  thickness  of swelling of the fibre.  single lamella, the c e l l  fibre  model.  lamellae coaxial highly  wall,  swollen  pulping  layers  fibre  causing  t o come  fibre  and  r e s w e l l i n g are accounted  by  C - Sample  The l o s s  specific  useful  tool  i fcorrectly  and  '  nique such  estimate altering does  of the dry-  area  on  drying  sealing of  either i n part  o r com-  bonds.  area  f o r determining distribution  applied.  Using  size  However  distribution  the  c a n be an this  available to small  a d r y and h i g h l y  while  between  The m e c h a n i s m o f  hydrogen  volume  of the pore  the structure.  cellulose  D - Freeze  technique  gas  molecules  without  t h e gas a d s o r p t i o n  outgassed  sample.  To  noticetechobtain  r e t a i n i n g the s t r u c t u r e o f the wet.water  sample  has been  the object  o f much  research.  Lodge  and Mason  Drying Van  (37)  much  require  a sample  swollen  the surface  saturated  from  and s u r f a c e  technique  and pore  can estimate  of  Adsorption  area  one  changes o f  t o be t h e r e v e r s e  surface  extremely  swollen F i g u r e -2  When a  f o r by t h e permanent  R e q u i r e m e n t s f o r Gas  has  between t h e  i s removed  the lamellae  gas a d s o r p t i o n  lies  wall.  of irreversible  water  as t h e p r o d u c t i o n  which  of porosity  between  formation  The  from  lamellae.  together.  i s seen  mechanism.  pletely  i s seen  i n the c e l l  ing  o f the spaces  dried  upon t h e  a completely  spaced  d r i e s the water  them  of a dried  depends  t h e s t r u c t u r e and s t r u c t u r a l  Chemical  cellulose  swelling  ably  whereas  by d i s s o l v i n g away m a t e r i a l  lamellae,  some  A fibre  c o n s i s t s o f s e v e r a l hundred  schematically p o r t r a y s this  o f which  den Akker  d r i e d wet mats  (36)  and M a r c h e s s a u l t ,  by f r e e z i n g a n d s u b s e q u e n t  sublimation  of the  -10-  FIGUBE2. MODEL a)  DRYING  OF  STONE  8  SCALLAN  CYCLE —  DRYING  —  SEATING  FULLY SWOLLEN  b)  PULPING  DRY c)  OF  WOOD  POSSIBLE  HO PARTIALLY SWOLLEW 2  UN SWOLLEN  WOOD  FULLY SWOLLEN PULP FI&RE  FIBRE  MODES OF FfBRE COLLAPSE  x  <  Ui OC  \A  m  -11water  (freeze  tension  (12)  nitrogen  that of  freezing  the -5  as  a  and  found  the  dried  most p a r t  and  -20  °C  and  and  liquid.  of  of  freezing  point  freeze gross  water  drying  - Solvent  Another sample  change  of  the  drying.  surface  was  Solvent  exchange  non-polar n-pentane.  This  an  pulp  of  the  drying  area the  water  easily those  of  and  pore  does not  fibres  Deryagin  extent  that  surface  bulk  found  such  water.  freezing point  bodies on  the  wetted  that  i n the  r e s u l t s of to  Puri,  de-  that  size.  the  Thus,  completely are  was  temperatures  i s held  cellulose fibres  method  adsorption  i n a water  Assaf  et  al  the eliminate  dried.  low  consists surface  is usually  but  for•obtaining a supposedly  swollen  (41)  i n solvent  drying of  which  the  water  the  depended  as  at  than  surface  results indicate  at  from  higher  function  conclusion  measured  commonly u s e d  retained  solvent  to  the  pulp  Drying  s u i t a b l e f o r gas  structure  this  dried  slightly  experimental  apparently  changes  Exchange  his  the  i n porous  technique  structural  that  considerably  depressions  be  surface  strength.  freeze  much a  unfrozen  close  held  of  temperature  support  (40)  tensile  however,  very  The  water  low  i t to  apparently,  Lakhanpal  pressions  E  w a t e r was  cellulose differ  Sharma and  the  concluded  (39)  Franks  properties  and  e l i m i n a t i n g the  area  dried pulp,  s a m p l e was  Merchant  supercooled,  (38)  as  adsorption f o r water  of  very  surface  temperature  removed.  of  the  expected  of  method  measured  the-freeze  for  This  e f f e c t y i e l d s sheets  Merchant by  drying).  claim  state that  exchange of  retaining  i s solvent  75  drying  percent with  r e p l a c i n g • the  tension  accomplished  such  pulp  as  first  ex-  of  the  ethanol.  water  benzene by  the  by  a  or  replacing  the  -12water  with  alcohol  an  with  solvents  a l c o h o l such the  considerable material  it.  success  remove  exchange  area  studies  of  that  found  that  the  wood  of  has  the  intermediate  been used  in preparation  from  cell  of  the  t i s s u e s but  results  do  not  polymerize  in his use  with  tissue  However, they  s t r u c t u r e by  of  Hunt  (19)  a.solvent  electron  of  solvent  o b j e c t i v e of  of  data  the  final  than  benzene.  sample  during  the  surface  area  with  p e n t a n e was  removed  by  stream  also  studied  from  cellulose  c o l l a p s e of  exchanging  one  the  during the  over  cellulose. a period  absolute  reached. methanol.  An  of  Both  found  dry  find  They  This  final  liquid  were  occuring  until  of  at  was  0®C.  water  might  s e v e r a l days  of  the  nitrogen  study  was  sample  that  process  a  alter-  a  r a p i d removal  sample  samples  a minimal  the  concentrations  identical  to  produced  of  exchange  solvent  procedure  surface  a maximum a r e a  the  on  swelling.  of  that  i n c r e a s i n g methanol was  by  possibility  expanded  sample  a  and  also  removal  for  w o r k was  liquid  They  drying  cotton  their  s t r u c t u r e produced as  have r e p o r t e d  exchange  samples  reproducible  used  the on  They  gradually  give  area  and  swollen  The  pentane  effect  methanol  several  exchange  dramatic  develop  expanded  surface  when t h e  with  to  would  temperature  in  liquid  Brownell  preparation  to  an  replacing  techniques.  ation  had  solvent  achieved  measurements.  larger  Sometimes  biologists  final  has  experiments  method  of  by  Forziati,  the  then  i n electron microscopy.  the  (42)  microscope  for  solvent.  technique  f o r use  Cote  their  methanol,  are. u s e d . This  usually  final  as  result done  by  with absolute  exchanged r a p i d l y  then  treated  -13-  i d e n t i c a l l y throughout t h e pentane exchange, d r y i n g and s u r f a c e area determination.  The s u r f a c e areas o f t h e two samples were  found t o be t h e same w i t h i n e x p e r i m e n t a l  error.  Merchant. ( 1 2 ) s t u d i e d s o l v e n t exchange d r y i n g w i t h r e s p e c t t o t h e e f f e c t s o f parameters such as t e m p e r a t u r e o f d r y i n g , s u r f a c e t e n s i o n and p o l a r i t y o f f i n a l s o l v e n t on.the s u r f a c e a r e a as d e t e r m i n e d by n i t r o g e n a d s o r p t i o n . and  Tables  1  2 a r e t a k e n from h i s work ( 1 2 ) w i t h t h e a d d i t i o n o f t h e  v a l u e s o f t h e s u r f a c e t e n s i o n a t 2 0 °C, and i n d i c a t e t h e p o s s i b i l i t y t h a t t h e s o l v e n t exchange d r i e d p u l p s do not have the same s t r u c t u r e as t h e water s w o l l e n p u l p s from which were d e r i v e d . because  they  T h i s d i f f e r e n c e i n s t r u c t u r e i s assumed  o f t h e wide range o f s u r f a c e areas found when  v a r i o u s s o l v e n t exchange d r y i n g parameters a r e v a r i e d . T a b l e 1 shows t h e s t r o n g r e l a t i o n s h i p between t h e s u r f a c e t e n s i o n o f t h e f i n a l s o l v e n t o f t h e s o l v e n t exchange p r o c e e d u r e and t h e B. E. T. s u r f a c e a r e a o f t h e samples. T a b l e 2 shows t h e i n t e r m e d i a t e as c r i t i c a l , but t h a t m o l e c u l a r  s o l v e n t s u r f a c e t e n s i o n i s not s i z e i s a p p a r e n t l y more  critical. F i g u r e s 3 and 4 which a r e from Merchant ( 1 2 ) demonstrate other aspects  o f whether o r not t h e water  swollen  s t r u c t u r e i s r e t a i n e d when a p u l p sample i s s o l v e n t exchange dried.  The dependence o f s u r f a c e a r e a on d r y i n g t e m p e r a t u r e  ( f i g u r e 3 ) f o r a g i v e n f i n a l s o l v e n t was found t o be d i r e c t l y p r o p o r t i o n a l t o t h e change i n s u r f a c e t e n s i o n .  However, t h e  e f f e c t o f r e s i d u a l l i q u i d s on s u r f a c e a r e a i s l e s s c l e a r and i s clouded  by t h e d i f f e r e n t d r y i n g t e m p e r a t u r e s used.  Table i : 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 * * P i n a l Exchange L i q u i d  B.E.T. Area  Surface  sq.m./g.  dyne/cm.  Benzene  43-0  28.88  Toluene Cyclohexane  48.1 88.5  28.52 24.99  n-Hexane  108  18.42  n-Pentane  129  16.00  Table 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 Intermediate Solvent  B.E.T. Area sq.m./g.  Area* Surface Tension 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 s o l v e n t i n a l l t e s t s . ** Tables 1 and 2 are from Merchant (12).  Tension  mu*& Z fftt&RAWN FROM MERCHANT 02))  EFFECTS OF SOLVENT EXCHANGE DRYING FROM VARIOUS HYDROCARBONS AT DIFTERENT TEMPERATURES  -16-  FIGURE 4. (REDRAWN FROM MERCHANT (12.))  60-  140  120  I0C-  o  CO  <  w  80-  cc  <•  UJ  6C -  *  00  4C-  zc -  A  N-PENTANE  y  N-HEXANE  €  CYCLOHEXANE  O  BENZENE  •  TOLUENE i  1.0  i  2.0 RESIDUAL  3.0 LIQUID  4.0 %  RELATIONSHIPS B E T W E E N FIBRE AREA AND RESIDUAL  LIQUID  -17Sommers (5) proposed t h a t one c o u l d e l i m i n a t e many o f the problems o f s o l v e n t exchange  d r y i n g by removing t h e f i n a l  solvent 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 solvent.  As a r e s u l t o f h i s and o t h e r s ' e x p e r i m e n t a l  work he c o n c l u d e d : " I n v o l v e d i n t h i s p r o c e s s ( s o l v e n t exchange d r y i n g ) a r e the p h y s i c a l and c h e m i c a l p r o p e r t i e s o f t h e l i q u i d s as w e l l as t h e c e l l u l o s e , t h e i n t e r a c t i o n s o f t h e s e p r o p e r t i e s , and a l s o t h e e f f e c t o f t h e s t r u c t u r e o f t h e c e l l u l o s e by way o f i t s p o r o s i t y and t h e way i n which t h e c e l l u l o s i c polymer u n i t s make up t h e m o l e c u l a r 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 v a l e n c e f o r c e s 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 s w o l l e n and f l e x i b l e by v i r t u e o f t h e s t r o n g r e l a t i o n s h i p between t h e water and t h e c e l l u l o s i c h y d r o x y l groups m a i n l y as t h e r e s u l t o f hydrogen bonding. Methanol i s t h e n added t o t h i s system i n an e f f o r t t o r e p l a c e t h e w a t e r . Removal o f some o f t h i s water q u i t e l i k e l y l e a d s t o a d e c r e a s e i n t h e expanded s t r u c t u r e t h r o u g h bonding o f c e l l u l o s i c h y d r o x y l s b e f o r e t h e s i t e s can be o c c u p i e d by methanol m o l e c u l e s . The degree o f t h i s l o s s i s not known but i t i s e x p e c t e d t h a t i t i s minor w i t h r e s p e c t t o l o s s e s which o c c u r l a t e r . A l l o f t h e water cannot be r e p l a c e d because i t i s not p o s s i b l e t o o b t a i n a completely water-free a l c o h o l . In addition, experimental e v i d e n c e shows t h a t some water s t i l l remains which c o u l d have been removed by i n c o n v e n i e n t l y l o n g time i n t e r v a l s o r some means o f m e c h a n i c a l a g i t a t i o n . T h i s water i s b e l i e v e d t o remain i n t h e s m a l l e s t pore s t r u c t u r e where t h e f o r c e s o f a t t r a c t i o n a r e t h e s t r o n g e s t and t h e l i m i t a t i o n s o f d i f f u s i o n a r e most pronounced. The o v e r a l l e f f e c t o f t h e water removal w i l l l i k e l y cause a s m a l l d e c r e a s e i n t h e expanded s t r u c t u r e and a s m a l l i n c r e a s e i n i t s r i g i d i t y t h r o u g h replacement o f p a r t o f t h e water by t h e l o w e r 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 o c c u r i n t h e attempt t o r e p l a c e the methanol by a n o n p o l a r l i q u i d . I t i s expected that the degree o f replacement w i l l be lower and t h e l o s s o f the s w o l l e n s t r u c t u r e h i g h e r t h a n i n t h e exchange o f water by a l c o h o l . T h i s a r i s e s from t h e attempt t o r e p l a 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 n o n s w e l l i n g n o n - p o l a r one. A lower e f f e c t i v e n e s s i n t h e exchange i s a l s o suggested by t h e f a c t t h a t s m a l l amounts o f m o i s t u r e can p r e v e n t complete m i s c i b i l i t y i n t h e p o l a r - n o n p o l a r system and t h a t c o n s i d e r a b l e u n r e p l a c e d methanol was found a f t e r a t t e m p t s t o r e p l a c e i t w i t h benzene.  -18-  E f f e c t s due t o removal o f t h e f i n a l s o l v e n t a r e c o m p l i c a t e d by t h e s m a l l amounts o f u n r e p l a c e d a l c o h o l and w a t e r . D r y i n g from t h e n o n p o l a r s o l v e n t 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 t h e c e l l u l o s e and t h r e e d i f f e r e n t l i q u i d s . I n m a c r o s c o p i c . t e r m s , each l i q u i d may be l o o k e d upon as c o n t r i b u t i n g t o t h e c o l l a p s e o f t h e s t r u c t u r e t h r o u g h i t s f o r c e s o f s u r f a c e t e n s i o n and i t s e f f e c t on t h e f l e x i b i l i t y of the s t r u c t u r e . Removal o f t h e 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 point eliminates the surface-tension forces of the f i n a l l i q u i d but o n l y i n t h o s e p a r t s o f t h e 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 r e p l a c e m e n t o f t h e a l c o h o l . These a r e a s o f complete replacement a r e most l i k e l y i n the l a r g e r pore r e g i o n s and t h e r e f o r e i t i s here t h a t t h e CP-method ( i . e . removal o f f i n a l s o l v e n t 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 t h e structure. The u n r e p l a c e d l i q u i d s c o n v e r s e l y show t h e i r e f f e c t m a i n l y i n t h e s m a l l e r pore r e g i o n s where because of i n c o m p l e t e replacement t h e s u r f a c e t e n s i o n o f t h e f i n a l l i q u i d i s o f l i t t l e consequence. F - Gas a d s o r p t i o n on C e l l u l o s i c  Materials  Sheppard and Newsome (43) used vapour isotherms  adsorption  i n an attempt t o d e t e r m i n e t h e s t r u c t u r e o f 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  c e l l u l o s e and v a r i o u s c e l l u l o s e d e r i v a t i v e s .  cotton  They a l s o  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 u s i n g t h e K e l v i n  cal-  equation.  However, no c o r r e c t i o n s were made f o r t h e a d s o r p t i o n o f t h e water m o l e c u l e s onto t h e w a l l s o f t h e s t r u c t u r e . remarkable i n i t s conception c a l c u l a t i o n a l techniques  T h i s work i s  o f t h e problem because most o f t h e  required 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 p u b l i s h e d a t t h a t  time.  I n 1932, Grace and Maass (44) s t u d i e d t h e a d s o r p t i o n of water v a p o u r , 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 . any e s t i m a t e s  of the area or s t r u c t u r e .  They d i d not make  -19-  Emmett and deWltt (10) s t u d i e d t h e a d s o r p t i o n o f n i t r o g e n on samples o f paper used as telephone  wire i n -  s u l a t i o n as p a r t o f a study o f t h e a p p l i c a b i l i t y o f t h e B.E.T. e q u a t i o n t o a wide range o f m a t e r i a l s .  They used vacuum d r i e d  papers and found t h e s t a n d a r d  "S" type i s o t h e r m  i s o t h e r m , BDDT c l a s s i f i c a t i o n  (page 7 r e f e r e n c e 20) y i e l d i n g  a l i n e a r B.E.T. p l o t . t h a t t h e B.E.T. e q u a t i o n  They concluded  (type I I  from these  results,;  c o u l d be a p p l i e d t o c e l l u l o s i c  materials. A s s a f , Haas and Purves ( 4 l ) noted t h e wide d e s crepancies  i n s u r f a c e areas and a c c e s s i b i l i t i e s o f c e l l u l o s e  when these  f a c t o r s a r e determined by water a d s o r p t i o n ,  n i t r o g e n a d s o r p t i o n and by t h a l l a t i o n s w i t h 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 e t h e r s . Rowen and B l a i n e (17) measured t h e a d s o r p t i o n of. n i t r o g e n and water vapour on a i r d r i e d p u r i f i e d w o o l , c o t t o n , s i l k , v i s c o s e r a y o n , n y l o n and a c e t a t e f i b r e s as w e l l as on titanium dioxide.  They found t h a t a l l o f t h e f i b r e s had a  r e l a t i v e l y low c a p a c i t y for. a d s o r p t i o n o f n i t r o g e n as compared w i t h t h e c a p a c i t y f o r a d s o r p t i o n o f water vapour. Table 3 shows the.magnitude o f t h i s d i f f e r e n c e .  Table  3 ( f r o m 17):  Material  Comparison o f Surface Areas Determined by W a t e r a n d N i t r o g e n A d s o r p t i o n  B.E.T, S u r f a c e A r e a s H 0 2  g 20°C  sq.m./g.  N  @-195°C  2  R a t i o o f Areas H 0  / N  2  sq.m./g.  Wool  206  0.96  215  V i s c o s e Rayon  204  0.98  208  Silk  140  0.76  184  Cotton  108  0.72  150  A c e t a t e Rayon  58.8  0.38  154  Nylon  45.0  0.31  145  Ti 0  7.0  7.90  0.9  2  They c o n c l u d e d  2  t h i s apparent  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. ii.  The a d s o r b i n g  s i t e s are not r e s t r i c t e d  to a surface.  I f the adsorbing sites are r e s t r i c t e d to a surface, 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 .  iii.  The i n t e r n a l s u r f a c e w i t h i n t h e 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 t h e presence o f a s w e l l i n g agent such as w a t e r .  iv.  The s m a l l e r d i a m e t e r a n d t h e p o l a r i t y o f t h e w a t e r molecule enable i t t o penetrate i n t o c a p i l l a r i e s not accessible to the nitrogen molecule. 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  they  d i d n o t e v a l u a t e t h e 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 , b u t p o i n t e d o u t t h e c o n c l u s i o n o f Stamm a n d M i l l e t the estimated values of c e l l u l o s e  (45)  that a l l  surface area i n the  -21literature which and  (prior  represented  a high  capillary ing  t o 1941)  fell  i>nto  two g r o u p s , a l o w group  "themicroscopically v i s i b l e  group which  represented  structure created  "the surface  within the c e l l  sults  of experiments  solvent  exchange  a n d Rowen  i n which  walls  dried cotton  are  shown i n f i g u r e 5 a n d t a b l e  were  t o methanol t o benzene.  a surface soaked  neutralized, soaked  adsorbed  linters.  water  found  (18) i n 1949  they  was  by t h e s w e l l -  area  i n cold then  o f 71.3  The s o l v e n t  The i s o t h e r m s  I i n appendix  sq.m/g.  exchange  dried.  Whe.n t h e a l k a l i  treated  s a m p l e was c o n d i t i o n e d  i n weight,  had an area  the surface  area  s q . 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$ surface  t o 2.1  the solvent  sq.m/g.  the  dried cellulose  and d r y i n g  l e d Hunt  of surface  to  workers  these  yielded  higher  area  that  rigorous  surface  Hunt, B l a i n e size (47).  distribution They  tribution  found  with  to small  using  sample,  o f 47.3  s q . m./g.  i n water  decreased  water  t o 31.6  t h e most  structure with  state.  those  o f water  indicated have  c a l c u l a t e d t h e pore  o f Wheeler  (46)  had a narrow pore  common p o r e  that  reported.  (18) a l s o  t h e method  small  The s e n - ,  e x c l u s i o n o f water would  a n d Rowen  vapour  decreased the  upon w e t t i n g  amounts  area's t h a n  t h e samples  that  e t a l (18) t o s u g g e s t  expanded m a t e r i a l i s i n an u n s t a b l e  sitivity  linters  The c o l l a p s e o f t h e e x p a n d e d  exchange  amounts o f w a t e r  They  A control  of alkali  gain  exchange  washed and  instead  a 3'3%  onto •  obtained  C.  f o rcotton  10% s o d i u m h y d r o x i d e ,  solvent  reported r e -  nitrogen  i n water  of  of the transient  agents". Hunt, B l a i n e  to  surface"  radius  being  and S h u l l  size about  dis  T  20 A  5  FIGURE D A T A  OF  NITROGEN  HUNT,  B L A I N E  ADSORPTION  ON  8  ROW E N  COTTON  A "ALKALI-SWOLLEN, SOLVENT EXCHANGE B - A  WITH  3.3%  WATER  C - A  WITH  11.0%  WATER  D -  C O N T R O L  REGAIN REGAII  (18) CELLULOSE  DRIED  f o r a l k a l i soaked l i n t e r s and I n the p r e s e n t  16 ft f o r water soaked  linters.  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 ( 4 8 ) and Grotjahn  found t o be e s s e n t i a l l y the same at 19 ft. and Hess (49)  used argon a d s o r p t i o n at  90°K t o study the e f f e c t s of b e a t i n g on the s o l v e n t exchanged B.E.T. s u r f a c e a r e a . Table 4:  T h e i r r e s u l t s are shown i n T a b l e  V a r i a t i o n of S u r f a c e Area of C e l l u l o s e B e a t e r Treatment.*  4.  with 2  Time Beaten  S u r f a c e Area (m  15 min.  184  30 min.  178  1 hour  200  2 hour  207  3 hour  188  4 hour  193  5 hour  195  These p u l p s were a p p a r e n t l y b u t a n o l which was  /g)  s o l v e n t exchange d r i e d w i t h  removed under vacuum at 100°C.  the s o l v e n t exchange d r y i n g t e c h n i q u e  However,  i s not e l a b o r a t e d upon  i n t h e i r paper Haselton  (13,50,51) s t u d i e d gas  a d s o r p t i o n on a  spruce wood, spruce p u l p , and paper made from t h i s p u l p . work can be c o n s i d e r e d was  i n three p a r t s .  a study of the n a t u r e  o f n i t r o g e n , n-butane and  The  f i r s t part  of the low temperature  00  (50)  adsorption  carbon d i o x i d e on f i n e l y  * S t r e c k e r - Muhle Model DKM  His  ground  -24(40 t o 100 mesh) specimens o f 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 p a r t (51) was a study o f t h e use o f  n i t r o g e n adsorption techniques  f o r a r e a and s t r u c t u r e s t u d i e s  on s o l v e n t exchange d r i e d sprucewood and sprucewood p u l p s . The  t h i r d p a r t , which w i l l be d i s c u s s e d i n a l a t e r s e c t i o n o f  t h i s work, was a study o f t h e bonded and unbonded s u r f a c e areas of papers as found by v a r i o u s methods i n c l u d i n g gas a d s o r p t i o n . As a r e s u l t o f t h e f i r s t p a r t o f h i s s t u d y , (50), concluded  that the nature  Haselton  of the a d s o r p t i o n of both  n-butane and n i t r o g e n on sprucewood, t h e c h l o r i t e  holo-  c e l l u l o s e and t h e KOH-extracted h o l o c e l l u l o s e i s such t h a t e i t h e r gas c o u l d be used f o r a r e a measurements on c e l l u l o s i c materials.  N i t r o g e n i s t h e p r e f e r r e d gas t o use because i t s  s m a l l e r , more s p h e r i c a l m o l e c u l e s have an a r e a which i s more d e f i n i t e l y known, and as i t d e v i a t e s l e s s from an i d e a l g a s , it  i s e a s i e r t o work w i t h .  Carbon d i o x i d e i s a p p a r e n t l y  s o l u b l e i n t h e 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 o f wood.and thus i s not  s u i t a b l e f o r s u r f a c e a r e a s t u d i e s when these  are p r e s e n t .  Besides  materials  t h i s problem, p l o t s of the decrease i n  f r e e energy and d i f f e r e n t i a l heat o f a d s o r p t i o n v e r s u s pressure  partial  and volume o f gas adsorbed r e s p e c t i v e l y i n d i c a t e d a  m o d e r a t e l y s t r o n g 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 o r n-butane. The  B.E.T., H a r k i n s  - J u r a (52) and F u - B a r t e l l (53) methods  o f computing s u r f a c e a r e a from a d s o r p t i o n d a t a were t r i e d and compared.  The B.E.T. method was s e l e c t e d as t h e best method  s i n 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 t h e  -25measurement  of fewer  points  on  the adsorption  than d i d the Harkins-Jura or F u - B a r t e l l Haselton determined dried KOH  (13,  nitrogen  51)  adsorption  given  chlorite  i n figure  6 and  F r o m t h e s e d a t a , t h e B. volume  distributions  KOH-extracted  Shull  (47).  the  same, w i t h  The  effect  area  and  m o i s t u r e on  the r e s u l t s  results and  study of the E.  T.  which  surface  shown i n f i g u r e s Merchant  pore  size  pore  pore  volume  size  8 and  as  distribution  increasing  through  He  E.  T.  5. reported  parameters  two  sets  of  sample.  listed (48)  of the  curve with  values.  concerned  a pulp  found  :  cellulose.  final  a function  drying.  B.  to those  primarily  of Pierce  of  holocellulose  of the  are  pore  essentially  given i n Table  exchange  rewetting  the method  exchange  chlorite  d i d determine  7 and  distributions  solvent  shaped  used  and  the method t o be  for cotton  of solvent  and  holocellulose  the accessible  (12,22) was  C.  having larger  similar  show t h e e f f e c t  of a i r drying  C.  (18)  a r e a , he  dramatically  effect  the  effects  are  are quite  Rowen  found  material  of benzene-dried, KOH-extracted  Hunt, B l a i n e  are  were  by  and are  2 of Appendix calculated  holocellulose  exchange  isotherms  f o r the c h l o r i t e  distributions  While Merchant  B.  a r e a s were  determined  of adsorbed  These  a  T.  of h i s work,  holocellulose  These  i n table  the KOH-extracted  was. d e t e r m i n e d  by  E.  part  sprucewood,  listed  chlorite  The  second  holocellulose. are  methods.  isotherms f o r solvent  (water-methanol-benzene)  extracted  and  i n the  isotherm  on  and  These  i n table  3  t o compute  essentially  the  isotherms  solvent  final  with  data  appendix the  solvents the  the magnitude  the  of  sameof  the  benzene-cyclohexane-n-pentane.  FIGURE  6,  NITROGEN  ISOTHERM  HASELTON  ( 13.  DATA  )  SOLID  o j A •  1  SYMBOLS -  DESORPTION  SPRUCEWOOD CHLORITE KOH  HOLOCELLULOSE  EXTRACTED -'  0.2  OF  0.4  0.6 P/R  CHLORITE  ""HOLOCELLULOSE __i  Q8  -27-  Ql  0  1  0.2  I  I  0.4  0.6 P/P.  1  0.8  L_  1.0  - 2 8 -  I  I  0  02.  I  I  0.4  0.6 P/P  9  i  I  0.8  I  \X>  -29Table 5*:  E f f e c t o f Adsorbed Water on the Area o f BenzeneD 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 M o i s t u r e Regained, p e r c e n t a g e of o v e n d r i e d weight  B.E.T. A r e a , 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  Merchant  0.64  (12) a l s o found t h a t a t m o s p h e r i c m o i s t u r e  must be r i g o r o u s l y e x c l u d e d from the d r i e d sample t o p r e v e n t l a r g e d e c r e a s e s i n the s u r f a c e a v a i l a b l e t o n i t r o g e n .  Previous  workers had not always t a k e n t h i s p r e c a u t i o n . Thode, Swanson and Becher (54) r e p o r t e d the r e s u l t s of n i t r o g e n a d s o r p t i o n on samples of wood p u l p which had been s o l v e n t exchange  d r i e d (water-methanol-n-pentane, w i t h the  pentane removed i n an atmosphere  of dry n i t r o g e n at 35-5°C).  The b l e a c h e d s u l f i t e c e l l u l o s e was of b e a t i n g i n a b a l l m i l l .  s u b j e c t e d t o v a r i o u s degrees  The r e s u l t s they r e p o r t e d are  g i v e n i n Table 6 and i n f i g u r e 9-  I n f i g u r e 9 t h e i r d a t a are  p r e s e n t e d .as c u m u l a t i v e pore volume l e s s than a p a r t i c u l a r pore  * From H a s e l t o n (13)  FIGURE  9  I N F L U E N C E AS  O F  B E A T I N G  DETERMINED  BY  O N  PORE  THODE.  DISTRIBUTION S W A N S O N  AND  IN  C E L L U L O S E  B E C H E R .  TIME  80 PORE  100  120  RADIUS,  140  «  160  180  200  220  240  ( 54.  MIN.  100  MIN.  260  )  B E A T E N  200  0  60  FIBRES  MIN.  -31radius. of  The  this  than  cumulative pore  6*:  the balance  volume o f pores  greater  radius.  Total Area B.E.T. Method sq. m./g.  Pore Area from Pierce calcd. sq. m./g.  on S o l v e n t Exchange, and Pore S i z e D I s t r i b u t  Median pore diam. ft..  Calcd. 32-44 ft diam. (liq. • N )  vol.  oores  80-200  ft diam.' (liq. N )  2  2  0  100  95  38.0  0.0550  0.0499  20  110  108  38.2  . 0542  .0584  50  123  115  37.8  .0546  .0601  100  149  128  38.0  . 0542  .0735  150  164  159  37.5  . 0647  .0926  200  185  170  37.4  .0607  cl447  250  202  178  38.5  .0657  .1153  The P i e r c e  method  distributions. pulps.is  concluded  plained new  These  since  function  From  (54)  to calculate  time, this  law f o r size  developed  the pore  t h e B.E.T.  of the time  t h e power i n p u t  by R I t t i n g e r ' s surface  used  authors noted  constant with  input. •  *  (48) w a s  a linear  that  essentially  that  pore  Nitrogen Adsorption Results D r i e d F i b r e s - B.E.T. A r e a s  Time of Ball Mill Beat ing min.  the  throughout  work a r e p r e s e n t e d as t h e pore  a particular  Table  volumes  surface  of beating.  of a b a l l  reduction  area of They  mill i s  phenomenon c o u l d  i s directly  volume  which  proportional  be e x states to  energy  -32-  The  p l o t of c u m u l a t i v e  pore volume v e r s u s  pore  s i z e ( f i g u r e 9) w i t h the time of b e a t i n g as a parameter i n d i c a t e s i n c r e a s e d pore volume began t o show up at about 22 ft pore r a d i u s : below t h i s v a l u e , b e a t i n g d i d not make very much d i f f e r e n c e except w i t h severe ment.  and c o n t i n u e d m e c h a n i c a l t r e a t -  However, the volumes of the l a r g e r pore s i z e s were  found t o have i n c r e a s e d w i t h b e a t i n g as i s shown i n Table 6 w i t h the 80-200 ft d i a m e t e r pore volumes. these phenomena, Thode et a l concluded  As a r e s u l t  that b a l l m i l l  of beating  of wood c e l l u l o s e c r e a t e s a d d i t i o n a l pores or f i s s u r e s i n the amorphous r e g i o n s of the f i b r e , pores a l l the way  or at l e a s t e n l a r g e s  down t o 50 ft or so i n diameter.  s e r v a t i o n t h a t the r e s u l t s of H a s e l t o n (12,22), Hunt et a l (18)  The  and  0.45  ob-  (13,50,51), Merchant  as w e l l as t h e i r own  showed a break  i n the d e s o r p t i o n n i t r o g e n i s o t h e r m between r e l a t i v e of 0.50  existing  pressure  r e s u l t i n g i n a most common pore s i z e of.about  20 ft r a d i u s l e d t o the c o n c l u s i o n t h a t the 20 ft r a d i u s 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 cellulose.  be r e l a t e d t o the b a s i c s t r u c t u r a l u n i t of  They f u r t h e r h y p o t h e s i z e d  b u i l d i n g b l o c k s of " s o l i d "  t h a t the elementary  c e l l u l o s e are l a i d down i n some s o r t  of a r r a y p e r m i t t i n g the r e g u l a r occurence of " h o l e s " a p p r o x i mately the s i z e of an elementary polymer u n i t . Sommers (5>55) i n an attempt t o r e t a i n the  highest  p o s s i b l e s u r f a c e a r e a f o r a s o l v e n t exchange d r i e d c o t t o n 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 t e m p e r a t u r e .  The  nitrogen  adsorption  -33Table J:  Sample  B. E. T. S u r f a c e Areas o f Samples Prepared by Sommers (5) • Treatment  Gas Adsorbed  S u r f a c e Area sq.m./g.  n-Pentane d r i e d  N,  46.8  n-Pentane d r i e d  N,  51.8  N,  51.8  COg removed above p o i n t **  critical  CC>2 removed above p o i n t **  critical  52.8  No treatment  H0 2  128  No treatment  H0 2  136  No treatment  H0  140  *  2  Sommers used c r o s s - s e c t i o n a l areas o f 16.2 and 10.5 ft p e r m o l e c u l e f o r N and R^O r e s p e c t i v e l y . 2  **  H i g h e s t v a l u e s r e p o r t e d . U s i n g a d i f f e r e n t source o f C 0 w i t h 4 p e r c e n t more m o i s t u r e ( t o t a l m o i s t u r e = 0.0647 mg. H 0 / g. C 0 ) the s u r f a c e a r e a was lowered t o 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 t o the moisture content o f t h e C0„. 2  2  2  :  B.E.T. s u r f a c e a r e a s were found t o d i f f e r  little  found where n-pentane was t h e f i n a l l i q u i d .  from those  They were b o t h  lower t h a n t h e B.E.T. areas c a l c u l a t e d from water vapour adsorption.  These r e s u l t s a r e g i v e n i n Table 7. Sommers (5 55) determined complete 3  nitrogen  i s o t h e r m s on a n-pentane d r i e d sample and two samples where t h e C0  2  s o l v e n t was drawn o f f above t h e c r i t i c a l p o i n t .  These  i s o t h e r m s a r e shown i n f i g u r e 10 and a r e l i s t e d i n t a b l e 4 o f appendix C.  A comparison o f t h e pore s i z e  distributions  c a l c u l a t e d by t h e method o f P i e r c e (47) showed t h a t d e s p i t e lower B.E.T. s u r f a c e a r e a s , t h e C 0 d r i e d samples p o s s e s s e d a 2  g r e a t e r t o t a l pore volume t h a n t h e n-pentane d r i e d  sample.  Most o f t h e i n c r e a s e d pore volume was i n t h e l a r g e r pore Table 8 Table 8:  sizes.  gives these f i g u r e s . S u r f a c e Area and Pore Volume f o r Isotherms by Sommers (5,56)  Sample D e s c r i p t i o n  B.E.T. Area  Determined  T o t a l Pore Volume determined a t 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 ( d r i e d by c o t t o n ) d r i e d  23.8  0.0745  C0  39-4  0.0752  2  2  dried  Some R u s s i a n w o r k e r s , O d i n t s o v and E r i n ' s h (56,57) s t u d i e d t h e s u r f a c e a r e a and pore s i z e d i s t r i b u t i o n i n wood and p u l p u s i n g benzene and hexane as t h e a d s o r b i n g gases.  Their  samples were p r e p a r e d by s o l v e n t exchanging from water t o  -36methanol and then t o the h y d r o c a r b o n used f o r a d s o r p t i o n . In one paper (56) i n which o n l y benzene was s o r b a t e , s u r f a c e a r e a s of 300 p o r t e d f o r sprucewood and  and  450  used as the  sq.m./g. were r e -  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 h a v i n g a r a d i u s of 30-1000 ft were r e p o r t e d t o be completely  absent i n the sprucewood but were p r e s e n t  holocellulose.  ad-  i n the  I n h o l o c e l l u l o s e the volume o f pores  a r a d i u s of 15-80 ft were.found t o predominate w i t h  almost  having  the  maximum i n the pore volume d i s t r i b u t i o n o c c u r i n g at 17-18 ft radius.  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 i n c r e a s e i n the volume of pores h a v i n g r a d i u s o f . o v e r 200  ft.  These f i n d i n g s , w i t h the  of the h i g h s u r f a c e areas (10 and  200  a  exception  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 b e i n g the u s u a l l y  accepted  v a l u e s ) are s i m i l a r t o those r e p o r t e d by o t h e r s u s i n g n i t r o g e n , n-butane, e t c . as  adsorbates.  I n a n o t h e r paper (57) benzene and hexane were used as adsorbates  t o 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 o f  celluloses. w i t h 2.5 5 and  These c e l l u l o s e s were:  percent  17-5  H C l at 100°C;  percent  percent  w i t h 75-80 ft r a d i u s .  Surface  o f the s u r f a c e a r e a .  NaOH I n c r e a s e d  Ex-  the volume of pores  A l l p r e p a r a t i o n s 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 d e t e r m i n e d from d e s o r p t i o n i s o t h e r m s respectively.  areas o f 300-400  D r y i n g o f the p u l p s 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 p e r c e n t t r a c t i o n w i t h 17-5  h o l o c e l l u l o s e hydrolysed  holocellulose extracted with  NaOH at20°C.  sq.m./g. were r e p o r t e d .  three  of benzene or hexane  -37-  Stone and S c a l l a n o f the Pulp and Paper Research I n s t i t u t e o f Canada have p u b l i s h e d a l a r g e volume o f work u t i l i z i n g n i t r o g e n a d s o r p t i o n t o study the s t r u c t u r e o f s o l v e n t exchange d r i e d p u l p s  (16,33,58-61).  Stone (58) i n 1963 p u b l i s h e d an e x t e n s i v e  review  of the l i t e r a t u r e concerned w i t h the porous s t r u c t u r e o f cellulosic materials.  He reviewed  microscopic  (particularly  e l e c t r o n ) , f l u i d flow, 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 a d s o r p t i o n and s o l u t e a c c e s s i b i l i t y methods f o r s t u d y i n g pore s t r u c t u r e .  As a r e s u l t o f h i s s u r v e y , he con-  c l u d e d t h a t i n s p i t e of t h e c o n s i d e r a b l e work done employing a wide v a r i e t y o f e x p e r i m e n t a l  techniques,  the amount o f  r e l i a b l e d a t a on t h e d e t a i l e d s t r u c t u r e o f t h e porous n a t i v e • c e l l u l o s e network was meagre and f r a g m e n t a r y . Stone and S c a l l a n (35) have r e p o r t e d on the e l e c t r o n m i c r o g r a p h and n i t r o g e n a d s o r p t i o n d a t a upon which they  based  the p o s t u l a t e d s t r u c t u r e o f t h e c e l l w a l l which was p r e v i o u s l y d i s c u s s e d i n s e c t i o n I I - B o f t h i s work.  They used a t r a n s -  m i s s i o n e l e c t r o n microscope t o study the f i b r e c r o s s - s e c t i o n s which were s t a i n e d w i t h p h o s p h o t u n g s t i c embedded i n epoxy.  a c i d p r i o r to being  The i s o t h e r m d a t a was o b t a i n e d u s i n g a  dynamic s o r p t i o n a p p a r a t u s o f which t h e d e s i g n and o p e r a t i o n i s the s u b j e c t o f r e f e r e n c e  (62).  They s t u d i e d a number o f  d i f f e r e n t p u l p s and r e p o r t e d t h e B.E.T. s u r f a c e a r e a and "pore volume" as c a l c u l a t e d from the a d s o r p t i o n o f n i t r o g e n at P/P  = Q  O.965.  These r e s u l t s a r e g i v e n i n T a b l e 9-  The d a t a o f 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 s u r f a c e a r e a and pore volume i n d i c a t i n g a c o n s t a n t  median pore  size.  Table 9:  B. E. T. Areas and Pore Volumes f o r a V a r i e t y Sample  Treatment  S o l v e n t exchanged from never dried state  Soaked, i n water and s o l v e n t exchange d r i e d Dried  from water a t 105 °C  B.E.T. S u r f a c e Area sq.m./g.  Pore Volume 0 - 300ft'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  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  cellulose  Bleached spruce s u l p h i t e  93  0.18  Spruce groundwood  25  0. 040  Sprucewood (microtome sections) Sprucewood (microtome sections) Unbonded p u l p f i b r e s  From Stone and S c a l l a n  3 to 6  0.6 t o 0.8 1.2 0.5 t o 1.0  Paper *  of Cellulosic Materials*  (35)  (0.006)  — 0.002  -39The a d s o r p t i o n and d e s o r p t i o n i s o t h e r m s f o r t h e s o l v e n t exchange  d r i e d f i b r e s were a n a l y s e d by t h e P i e r c e ( 4 8 )  method and I n b o t h c a s e s , t h e most common pore r a d i u s was found t o be i n t h e 16-20 ft range f o r a l l samples.  They  d e t e r m i n e d t h e median pore s i z e ( d e f i n e d as t h e pore s i z e a t which one h a l f o f t h e t o t a l pore volume i s c o n t a i n e d i n s m a l l e r pores"and one h a l f i n l a r g e r p o r e s ) by two methods: from t h e cummulative d i s t r i b u t i o n curve and from t h e r e l a t i o n ship. r  med =  2  X  (0.965) A  (1.)  A good c o r r e l a t i o n between t h e methods was found w i t h t h e v a l u e s d e t e r m i n e d r a n g i n g between 32 and 38 ft. T h e i r e l e c t r o n m i c r o g r a p h s (35) w a l l has a tendency t o s p l i t  showed t h a t t h e c e l l  i n t o l a m e l l a e ( p o s s i b l y caused by  s w e l l i n g o f t h e epoxy embedding r e s i n i n pores between l a m e l l a e ) and t h e s e  l a m e l l a e a r e more o r l e s s c o n c e n t r i c w i t h t h e f i b r e  axis. The l o s s o f s u r f a c e a r e a ( n i t r o g e n a d s o r p t i o n ) o f s o l v e n t exchange  d r i e d wood p u l p , 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 h e a t i n g was t h e s u b j e c t o f a n o t h e r paper by Stone and S c a l l a n (59).  Changes i n t h e pore s i z e d i s t r i b u t i o n o f  b l e a c h e d spruce s u l p h i t e p u l p s were a l s o d i s c u s s e d . experimental technique involved a s o l v e n t exchange  The  water-methanol-hexane  w i t h t h e hexane removed a t room t e m p e r a t u r e  i n a stream o f d r i e d n i t r o g e n .  The s u r f a c e a r e a was t h e n  measured and t h e sample heated t o t h e d e s i r e d t e m p e r a t u r e i n an a i r b a t h f o r 30 minutes w h i l e b e i n g purged w i t h a d r y  -40helium-nitrogen  mixture.  The r e s u l t s o f t h e s e  e x p e r i m e n t s 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 o f s u r f a c e a r e a w i t h t e m p e r a t u r e s t a r t i n g a t 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 n o t e d and t h e s e were t h o u g h t t o be r e l a t e d t o t h e t h e r m a l  s o f t e n i n g temperatures  o f t h e s e m a t e r i a l s o f about 195°C and 217°C r e s p e c t i v e l y as measured by G o r i n g  (63).  Merchant (22) areas are obtained  showed t h a t h i g h e r s p e c i f i c  from a sample i f t h e s u r f a c e t e n s i o n o f  the f i n a l s o l v e n t i s r e d u c e d d u r i n g e v a p o r a t i o n d r y i n g temperature.  surface  by r a i s i n g t h e  He a l s o p o i n t e d out t h a t p r o l o n g e d e x -  posure t o t e m p e r a t u r e s above 60°C r e s u l t e d i n l o s s o f s u r f a c e area.  Stone and S c a l l a n (59) p r e p a r e d . t h r e e  the hexane b e i n g removed a t 0, 25, and 50°C. crease noted.  samples w i t h A marked i n -  o f s u r f a c e a r e a w i t h i n c r e a s e d d r y i n g t e m p e r a t u r e was These samples a l l r e v e r t e d t o t h e same s u r f a c e  area  when heat t r e a t e d a t l80°C. The  changes i n pore s u r f a c e a r e a d i s t r i b u t i o n were  measured by t h e s e . w o r k e r s (59).  One e f f e c t o f h e a t i n g a  s o l v e n t exchange d r i e d p u l p i s l o s s o f pore volume, w i t h t h e g r e a 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 h e a t e d t o e l e v a t e d t e m p e r a t u r e s 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 s u r f a c e a r e a s , r e v e r t e d t o t h e i r o r i g i n a l s o l v e n t exchange d r i e d s u r f a c e a r e a s when soaked i n w a t e r and s o l v e n t exchange d r i e d a second t i m e .  X-ray d i f f r a c t i o n d a t a and s c a n n i n g  electron  .-Ill-  m i c r o g r a p h s of the samples b e f o r e and a f t e r h e a t i n g 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 of off  the heated specimens i n the m i c r o g r a p h s .  appearance  The vapours  d u r i n g heat t r e a t m e n t were a n a l y s e d w i t h a gas c h r o -  matograph.  Hexane was e v o l v e d at the l o w e s t t e m p e r a t u r e w i t h  water e v o l u t i o n commencing at about 100°C. e s s e n t i a l l y ceased e v o l u t i o n at l45°C.  Both m a t e r i a l s  Very l i t t l e  methanol  was d e t e c t e d and no carbon monoxide and c a r b o n d i o x i d e , at  driven  even  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 t h a t the  c e l l u l o s e was b r e a k i n g down. At the symposium " C o n s o l i d a t i o n o f the Paper h e l d at Cambridge, E n g l a n d , ' i n September,  Web"  19-65, Stone and  Scallan  (16) p r e s e n t e d a paper w i t h the s t a t e d purpose o f e x a m i n i n g i n d e t a i l the e x a c t manner i n w h i c h 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 t h r e e  p o s s i b i l i t i e s f o r t h i s accommodation o f w a t e r : i. ii. iii.  I t c o u l d e n t e r c a p i l l a r i e s a l r e a d y p r e s e n t i n the dry fibre I t c o u l d 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 t h a t were p r e v i o u s l y j o i n e d  I t c o u l d form a m o l e c u l a r 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 p r o d u c i n g no r e a l surfaces.  These t h r e e p o s s i b i l i t i e s were examined i.  surfaces  separately.  Low a n g l e s c a t t e r i n g o f X-rays (64,65) and n i t r o g e n a d s o r p t i o n (35) t e c h n i q u e s have been used t o show the e x i s t e n c e of a s m a l l ( l e s s t h a n 0 . 5 $ )  volume o f pores  i n the s i z e range o f 20-300 & e q u i v a l e n t r a d i u s i n dry  native c e l l u l o s i c fibres.  Mercury  intrusion  t e c h n i q u e s have a l s o been used  (66) and w i t h t h e s e  i t was found t h a t t h e volume o f pores s m a l l e r t h a n 0.3 m i c r o n s was l e s s t h a n 0.02 c.c./g i n d r y b l e a c h e d spruce s u l p h i t e p u l p f i b r e s . t h a n 0.3 microns  s h o u l d be v i s i b l e  Pores  microscopically  but o p t i c a l and s c a n n i n g e l e c t r o n m i c r o g r a p h s have f a i l e d t o r e v e a l any such p o r e s .  (16)  Thus i t was  c o n c l u d e d t h a t pores do e x i s t w i t h i n t h e c e l l of  larger  wall  d r y 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 s h o u l d have l i t t l e  i n f l u e n c e on t h e r e -  l a t i o n s h i p between water uptake and t h e 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 o f 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  s o l v e n t exchange d r y i n g and gas a d s o r p t i o n have l e d to  g e n e r a l agreement on t h e f o l l o w i n g p o i n t s as  e x p r e s s e d by Stone and S c a l l a n : (a)  The s p e c i f i c s u r f a c e a r e a o f f i b r e s from water i s about 1 sq.m./g.  dried  (b)  The s p e c i f i c s u r f a c e a r e a o f w a t e r - s w o l l e n f i b r e s d r i e d by s o l v e n t exchange i s many t i m e s g r e a t e r than 1 s q . m./g., v a l u e s r a n g i n g up t o 200 s q . m./g.  (c)  The pores t h a t a r e r e s p o n s i b l e f o r t h e l a r g e surface area of swollen f i b r e s are s m a l l , the most common pore s i z e b e i n g o f t h e o r d e r of 16-22 ft r a d i u s and t h e median pore s i z e ( t h a t s i z e above and below which e x i s t s 50 p e r c e n t o f t h e t o t a l volume) i s about 35 ft radius.  The by a  large  nitrogen solvent  must as  difference i n surface molecules  exchange  be c o n t a i n e d  the surface  separation The  water  bulk  water  placed drying.  dried  Thus  open pores  recognized  fibre  fibre  of pores  that  i n these  produced  elements  as water  must  have  materials  during  i t was c o n c l u d e d  by s e p a r a t i n g  surfaces  entered.  exchange  water  that  of the  a n d be r e -  solvent that  by t h e  some  as i t can mix w i t h  area  presumably  were  pores  and  indicates surface  within the wall i t s e l f ,  properties  by o t h e r  as  between a n a i r d r i e d  of structural held  areas  could  were  previously  j oined. Stone pore  and S c a l l a n volume  content been  of pulp  40  solvent  percent  by  exchange  one-fifth fibres  with  decreasing on samples  from  i n pulp  fibres  must  form  the cellulose  have p u b l i s h e d  i s not found  some t y p e  present  exchange  dry-  of the water detectable  i t was c o n c l u d e d  this  association  Recently,  some a c c e s s i b i l i t y  than  adsorption  i n pores  of molecular  molecules.  (less  of the water  to the solvent  techniques  moisture  pulps  by n i t r o g e n  o f t h e volume prior  which had  i n t a b l e 10.  of the drier  detected  i n total  moisture  the various  as a s u b s t a n t i a l f r a c t i o n  gas a d s o r p t i o n  water  dried  volume  moisture)  Thus,  present  adsorption  t h e pore  the pulp  ing.  with  t h e changes  Their'results are l i s t e d  found  was o n l y in  fibres  by n i t r o g e n  contents. They  (16) determined  results  these  workers  which  indicate  -44Table 10: Porous S t r u c t u r e a t V a r i o u s Stages o f D r y i n g a t 25°C Water p r e s e n t b e f o r e s o l v e n t exchange drying percent  95  *  3 cm / g .  20  Specific Surface, sq.m./g. B.E.T.  Pore volume, cm /g i n pores t o 300 ft  Pierce  Experimental  Pierce  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 o f water x 1 0 0 ) / (weight o f s o l i d s + water) 3 Volume o f n i t r o g e n ( i n cm at p/p = 0 . 9 6 5  l i q u i d ) sorbed by t h e sample  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 .  are d i s c u s s e d i n s e c t i o n s I I - K and  These r e s u l t s IV-D.  At the Cambridge symposium Stone and S c a l l a n p r e sented the r e s u l t s of some experiments d e t e r m i n i n g the changes i n a r e a 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 p u l p samples.  One  s e r i e s was d r i e d t o  a measured water c o n t e n t and t h e n s o l v e n t exchange d r i e d u s i n g the water-methanol-pentane  sequence w i t h the pentane  i n a stream of dry n i t r o g e n at 25°C.  The  removed  second s e r i e s  was  d r i e d t o a known m o i s t u r e c o n t e n t , soaked i n water o v e r n i g h t and t h e n s o l v e n t - exchange d r i e d .  Nitrogen adsorption  i s o t h e r m s were determined on a l l  samples and B.E.T. and a  P i e r c e a n a l y s i s made.  The r e s u l t s of t h e s e experiments are  g i v e n i n T a b l e s 10 and 11 and F i g u r e 11. The r e s u l t s of t h e s e experiments l e d Stone and  Scallan  t o the c o n c l u s i o n t h a t t h e r e are a p p a r e n t l y two t y p e s of pores o f about e q u a l volume.  One  type c l o s e d i r r e v e r s i b l y d u r i n g  d r y i n g , commencing at about 50 p e r c e n t m o i s t u r e and became more or l e s s c o m p l e t e l y c l o s e d at 30 - 40 p e r c e n t m o i s t u r e .  The ,  second t y p e , which can be reopened w i t h w a t e r , s t a r t e d t o c l o s e a t 30-40 p e r c e n t m o i s t u r e and c o n t i n u e d t o c l o s e u n t i l dryness was reached.  E x a m i n a t i o n of the pore s i z e  complete  distributions  by these workers r e v e a l e d 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 t h e r e 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.  -46FIGURE  CHANGE  II.  OF  (REDRAWN  PORE  FROM  V O L U M E  REFERENCE  DURING  16.)  DRYING  O-  O  PARTIALLY  DRIED  V  P A R T I A L L Y  DRIED  AND  20  40  PERCENTAGE  60 WATER  R E S W O L L E N  »  80  100  -47-  Table 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 a n d R e s w e l l i n g i n W a t e r  Water* t o which f i b r e s reduced before r e s w e l l i n g , p e r cent  Specific surface, sq.m./g.  P o r e v o l u m e , cm / g i n p o r e s t o 300 ft  B.E.T.  Pierce  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  _  * Percentage water c a l c u l a t e d (weight o f s o l i d s + water) ** Volume o f n i t r o g e n a t p / p ^ = 0.965  ( i n cm  Experimental**  Pierce V •P  as ( w e i g h t o f w a t e r x 1 0 0 ) / liquid)  s o r b e d by t h e sample,  -48-  G - I n t e r p r e t a t i o n of Gas A d s o r p t i o n R e s u l t s i n Terms of 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 .  The  Stone and S c a l l a n d i s c u s s e d these r e s u l t s i n terms o f the model of c e l l u l o s e f i b r e they proposed and which has d e s c r i b e d i n s e c t i o n I I - B of t h i s work.  been  They p o s t u l a t e d 'that  d r y i n g c o u l d cause l a m e l l a e t o move t o g e t h e r and cause the spaces between them t o c l o s e c o m p l e t e l y , inward  one  a f t e r another,  radially  from the e x t e r i o r of the f i b r e toward the lumen.  would thus be e i t h e r c o m p l e t e l y  open or c o m p l e t e l y  Pores  closed,  except i n the t r a n s i t i o n zone, w h i c h , i f narrow enough, would be i n s u f f i c i e n t t o 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 . support  In  of t h i s model t h e r e i s the work of Hermans (67)  Greyson and L e v i (68).  Hermans (67)  verse process, moistening r a d i a l l y inward  and  r e p o r t e d t h a t the r e -  of a dry rayon f i l a m e n t , proceeds  from a s h a r p l y d e f i n e d moistened mantle t o  the core of the f i l a m e n t which r e t a i n s i t s i n i t i a l m o i s t u r e  con-  t e n t . - Greyson and L e v i , (68) s t a r t i n g w i t h water s w o l l e n  cotton  f i b r e s s o l v e n t exchange d r i e d , measured the s u r f a c e a r e a  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 w i t h a s m a l l amount of water vapour, e v a p o r a t e d the water and remeasured the area.  The  second s u r f a c e a r e a was  A d d i t i o n a l treatments  l e s s t h a n the  surface  original.  w i t h water vapour had no e f f e c t on  s u r f a c e a r e a u n t i l the amount of m o i s t u r e of the f i r s t a d d i t i o n .  the  added exceeded t h a t  T h i s r e s u l t i m p l i e s t h a t water e n t e r s  the same r e g i o n of the f i b r e on s u c c e s s i v e a d d i t i o n s as i t did  on the i n i t i a l a d d i t i o n and  s w e l l s these r e g i o n s , o n l y  moving deeper i n t o the f i b r e when the a d d i t i o n of water ceeds t h a t p r e v i o u s l y added.  ex-  -49-  H - D i s t r i b u t i o n o f Water i n t h e C e l l W a l l Stone and S c a l l a n (16) used F i g u r e 12 t o 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 b l e a c h e d spruce s u l p h i t e pulp at various moisture contents.  The d a t a o f T a b l e  10 show t h e pore volume measured at any s t a g e o f d r y i n g i s cons i d e r a b l y l e s s t h a n t h e volume o f water p r e s e n t p r i o r t o s o l v e n t exchange d r y i n g .  At low m o i s t u r e c o n t e n t ( l e s s t h a n 40%). t h e  pore volume measured i s a c o n s t a n t f r a c t i o n ( o n e - f i f t h ) o f t h e water p r e s e n t , assuming water r e t a i n s a d e n s i t y o f 1.0 gm./c.c. Thus i f , t h e f o u r f i f t h s water i s not i n p o r e s , i t must be. p r e sent i n t h e " s o l i d " l a m e l l a e as g e l or m o l e c u l a r l y bound water and i s removed d u r i n g s o l v e n t exchange w i t h o u t l e a v i n g pore  ;  space. I n t e r e s t i n g l y , the s o l u t e a c c e s s i b i l i t y method  (69)  ( d i s c u s s e d i n s e c t i o n s I I - K and IV-D) d e t e r m i n e s a t o t a l pore volume o f about 5 times t h e pore volume d e t e c t e d by gas adsorption.  With the s m a l l m o l e c u l a r probes  (Einstein-Stokes  diameter o f 8 ft) v i r t u a l l y a l l o f 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 t h e water i s h e l d i n some form of p o r e . Thus, i t would appear t h a t a l a r g e p o r t i o n o f t h e pores c o u l d be l o s t when a p u l p is- s o l v e n t exchange d r i e d . I - E f f e c t of B e a t i n g on S u r f a c e Area o f S o l v e n t Exchange Dried Pulps These workers (16) a l s o s t u d i e d t h e e f f e c t o f b e a t i n g on s u r f a c e a r e a o f p u l p s t h a t were: never d r i e d ; d r i e d over P 0 2  5  at 25 °C; d r i e d at 105 °C; and d r i e d at 105 °C f o l l o w e d  by heat t r e a t m e n t at 150 °C.  A l l t h e p u l p s were r e s w o l l e n w i t h  -50FIGURE 12. (REDRAWN FROM REFERENCE 16) THE DISTRIBUTION OF WATER  PERCENT  WATER  IN PULP FIBRES  water  and  solvent  determination. all  exchange d r i e d The  cases, the  results  prior  are  to  surface area  shown i n f i g u r e  4l.  In  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  of  beating.  J  - The  has  on  Influence of Composition  on  A  the  study of the  i t s porosity  materials and  used  sulphite  filament dried  and  pulps, a and  and  a  for  dried  tribution of  of  sizes  not  molecule  preferred The  pore  which  rather causes  shift  unbleached  kraft  fraction  i n the  size  based  on  a l l the  distributions  l e d Stone fibres  controlled  never  reswollen.>  were done on  i n native  fibre The  hollow  pore  Area  made.  a  which  and have a  nor  a  dis-  function  some p r o p e r t y o f . t h e  i t to aggregate  of the median pore  dried  a t 105  °C  t o a more permament  plastic  deformation of larger  as  The  biologically but  also  105°C a n d  analysis  the pores  This effect  stress  at  similar  size.  the  hour  Surface  into  certain  arrangements.  samples are  attributed  groundwood  samples.  that  chemical treatment  cellulose  the  and  were v e r y  to suggest  b e h a v i o r was  alpha cellulose,  f o r one  exchange d r i e d  a l l specimens  Scallan  spruce  and  composition of the  s p r u c e b l e a c h e d and  spruce  B.E.T. s u r f a c e a r e a s solvent  drying  included  rayon  state  influence  Porosity  was  relaxation  r e p o r t e d by Stone  closure  i n dried  Scallan  pores  to a lower value  r e s w o l l e n i n water of the pores  c o n s i d e r e d t o be  Robertson and  and  size  by  fibres  a result  a mechanism  of  was larger  of the  easier  similar  with increasing  when  to  temperature  (70). (60)  performed  a series  of  experiments  -52to  d e s c r i b e t h e changes o f p o r o s i t y o f wood p u l p w i t h de-  creasing y i e l d .  Wood meal and groundwood p u l p were de-  l i g n i f i e d by c h l o r i n e - m o n o e t h a n o l a m i n e t r e a t m e n t s  w h i c h were  presumed t o remove o n l y t h e l i g n i n l e a v i n g t h e h o l o c e l l u l o s e . The groundwood  p u l p and wood meal had i n i t i a l  o f about 40 and 5 sq.m./g. r e s p e c t i v e l y .  surface areas  The s u r f a c e  area  and p o r o s i t y as d e t e r m i n e d by s o l v e n t exchange d r y i n g and nitrogen adsorption increased with decreasing r e t a i n i n g approximately  lignin  the d i f f e r e n c e i n i n i t i a l  content,  values.  I n t h e second s e t o f e x p e r i m e n t s t h e s u r f a c e a r e a and p o r o s i t y o f k r a f t and s u l p h i t e b l a c k s p r u c e p u l p s o f v a r i o u s  yields  were m o n i t o r e d by s o l v e n t exchange d r y i n g and n i t r o g e n adsorption.  T h e i r r e s u l t s were i n t e r p r e t e d a s : The r e m o v a l o f l i g n i n o r l i g n i n and c a r b o h y d r a t e from wood f i b e r s l e a v e s s m a l l p o r e s i n t h e s w o l l e n c e l l wall. These have a median s i z e w h i c h c o v e r s t h e range f r o m 20-40A\  2.  As m a t e r i a l i s removed from t h e c e l l w a l l , t h e 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 a t 100% y i e l d and r e a c h e s a maximum a t 65-70% y i e l d , , a t w h i c h p o i n t the s w o l l e n c e l l w a l l c o n t a i n s s l i g h t l y more v o i d t h a n s o l i d volume. According to the m u l t i l a m e l l a r concept, t h e d e v e l o p i n g p o r o s i t y i s i n t e r p r e t e d as the p r o g r e s s i v e s u b d i v i s i o n o f 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 l a m e l l a e u n t i l a t t h e maximum t h e s e a r e o n l y 35-40 R. t h i c k . The p o r e s a r e t h e n t h e s l i t - l i k e s p a c e s between t h e s e l a m e l l a e , and i n c r e a s e w i t h the number o f l a m e l l a e .  3.  I f t h e pore volume i s compared w i t h t h e volume o f m a t e r i a l removed from t h e c e l l w a l l , i t i s found t h a t t h e p o r o s i t y v s . y i e l d c u r v e s may be d i v i d e d i n t o t h r e e zones. From 90-100% y i e l d , the pore volume i s a p p r o x i m a t e l y e q u a l t o t h e volume o f m a t e r i a l removed. From 67-90% y i e l d , t h e pore volume exceeds t h e volume o f m a t e r i a l removed, t h a t i s , s w e l l i n g o f t h e 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 d e c r e a s e s 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 cont r a c t i o n o f the c e l l w a l l . T h i s c o n t r a c t i o n o f the c e l l w a l l towards the end o f 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 o f the s w e l l i n g caused d u r i n g growth by the  -53intussusception  K - Solute  of l i g n i n .  A c c e s s i b i l i t y of C e l l u l o s i c In a s e r i e s of papers  solute  accessibility  properties.  (69,71-74) S t o n e e t a l u s e d  t o study a wide v a r i e t y o f c e l l u l o s e  Included are studies  o f k r a f t and s u l p h i t e b l a c k of never d r i e d  Materials  and d r i e d  of the s w e l l i n g  behavior  spruce pulps at d i f f e r e n t y i e l d s ,  and r e s w o l l e n  bleached pine  sulphate  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 fractions and  subjected to various  beating,  of regenerated c e l l u l o s e . The s o l u t e  water i n a c c e s s i b l e  exclusion  Diameter  =  by t h e E i n s t e i n - S t o k e s ,  — — 3TT  T a b l e 12 g i v e s  t e c h n i q u e measures t h e volume o f  t o polymer molecules of d i f f e r i n g hydro-  dynamic d i a m e t e r s as c a l c u l a t e d  by  d e g r e e s of. P . F . I , m i l l  nDN  formula.  (2) Q  the c h a r a c t e r i s t i c s of the macromolecules  S t o n e e t a l ( 6 9 , 72-74). A known t o t a l w e i g h t o f t h e p o r o u s c e l l u l o s i c  swollen  sealed cules  material,  i n an e x c e s s o f w a t e r , h a s a m e a s u r e d v o l u m e 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  is  used  and m i x e d t h o r o u g h l y a l l o w i n g  added.  time f o r t h e macromole-  t o d i f f u s e i n t o the pore s t r u c t u r e .  o b t a i n e d , a sample o f t h e l i q u i d  of the c o n c e n t r a t i o n washed, d r i e d initially  The s y s t e m i s  After  equilibrium  i s removed f o r a n a l y s i s  of solute, the c e l l u l o s i c  material i s  a n d w e i g h e d t o d e t e r m i n e t h e amount o f w a t e r  present.  I f a l l the water o r i g i n a l l y  associated  -54-  T a b l e 12 *:  P r o p e r t i e s o f M a c r o m o l e c u l e s Used by S t o n e a n d Scallan  Macromolecule  Molecular weight M w  M M  w n  Molecular diameter i n s o l u t i o n , ft  Glucose  180  1.0  8  Maltose  342  1.0  10  Raffinose  504  1.0  12  Stachyose  666  1.0  14  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 10  -  560  24,000  24 x 1 0  * Prom r e f e r e n c e  (69)  Dextran  6  6  —  1600  -55w i t h t h e porous body i s a c c e s s i b l e t o t h e s o l u t e m o l e c u l e s , 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 . the s o l u t e m o l e c u l e s the water  If  are too large t o enter the smaller pores,  i n t h e s e p o r e s 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 t h e  s o l u t i o n a f t e r m i x i n g w i l l be somewhat l e s s d i l u t e t h a n i n t h e first of  case.  This difference i n concentration i s the basis  a s i m p l e c a l c u l a t i o n t o g i v e t h e amount o f water i n -  a c c e s s i b l e to the solute.  When t h e s o l u t e m o l e c u l e s a r e  t o o l a r g e t o e n t e r t h e pore s t r u c t u r e a t a l l , t h e i n a c c e s s i b l e F i g u r e 13 demon-  water e q u a l s t h e t o t a l water o f s w e l l i n g .  s t r a t e s t h e t y p e o f d a t a o b t a i n a b l e by t h i s method. these  are In  g i v e n i n t a b l e 6 o f appendix  Some o f  C.  t h e s t u d y by a c c e s s i b i l i t y measurements on t h e  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 spruce of  pulps  a wide range o f y i e l d s , Stone and S c a l l a n ( 6 9 ) found t h a t  b o t h p u l p i n g p r o c e s s e s c o u l d be d i v i d e d i n t o two s t a g e s ; 100  t o 60 p e r c e n t y i e l d and below 60 p e r c e n t y i e l d .  from  In the  k r a f t p u l p s , t h e wet c e l l w a l l s t a y e d c o n s t a n t i n volume down to  60 p e r c e n t y i e l d , w i t h water r e p l a c i n g t h e s o l i d m a t e r i a l  leaving the wall.  However, f o r t h e s u l p h i t e p u l p s over t h e  same y i e l d range t h e c e l l w a l l s t e a d i l y s w e l l e d as components were removed. of  These workers  postulated that t h i s  t h e s t r u c t u r e o f s u l p h i t e f i b r e s may account  disruption  f o r the  s u l p h i t e p u l p b e i n g weaker t h a n t h e e q u i v a l e n t k r a f t p u l p . As t h e y i e l d was l o w e r e d below 60 p e r c e n t , t h e c e l l w a l l s o f b o t h k r a f t and s u l p h i t e p u l p f i b r e s c o n t r a c t e d . p u l p f i b r e s always  The s u l p h i t e  c o n t a i n e d more water t h a n t h e k r a f t a t a  FIGURE 13.  THE ACCESSIBILITY  DATA OF STONE AND SCALLAN  ( 6 9 ) (PHOTO)  -57-  particular yield. contained  W i t h i n the c e l l w a l l , the water  was  i n pores whose average s i z e i n c r e a s e d as p u l p i n g  proceeded;  those  i n the s u l p h i t e p u l p f i b r e s always  somewhat l a r g e r t h a n the k r a f t f i b r e s of e q u i v a l e n t  being yield.  A comparison between the r e s u l t s f o r p u l p s  of  v a r i o u s y i e l d s r e p o r t e d by these workers (60) u s i n g 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 and the  data  o b t a i n e d 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 o b v i o u s 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 d e t e r m i n e d by the  accessibility  method i s at l e a s t t w i c e t h a t d e t e r m i n e d by gas techniques.  The  adsorption  gas a d s o r p t i o n method i n d i c a t e s a maximum  pore volume o c c u r s at about 60-70 p e r c e n t rapidly with further pulping.  The  yield,  decreasing  accessibility  data  i n d i c a t e the t o t a l pore volume i n c r e a s e s as the y i e l d creases  t h r o u g h o u t the range s t u d i e d (100-50 p e r c e n t  These d i s c r e p a n c i e s may  deyield).  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 d u r i n g s o l v e n t exchange d r y i n g , which i s h i n d e r e d where the y i e l d i s 60-70 p e r c e n t  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 components of the wood.  other n o n c e l l u l o s e  At h i g h e r y i e l d s b o t h methods i n -  d i c a t e a lower pore volume.  At lower y i e l d s , the  c e l l u l o s e components are not p r e s e n t  in sufficient  nonquantity  t o a r r e s t the c o l l a p s e of the pores d u r i n g s o l v e n t exchange drying. I n s t u d i e s of a c c e s s i b i l i t i e s on p i n e p u l p s , St-one et a l (72,73) found t h a t 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 p u l p , d r i e d and  re-  -58-  s w o l i e n p u l p , beaten p u l p and p u l p s cooked by t h e k r a f t o r s u l p h i t e processes. 25 t o 560 ft d i a m e t e r , s t a n t i a l decrease. crease  F o r pores a c c e s s i b l e t o m o l e c u l e s  of  d r y i n g and r e s w e l l i n g caused a subBeating i n i t i a l l y  caused a s l i g h t i n -  i n s w e l l i n g o f never d r i e d k r a f t p u l p s , however,  f u r t h e r b e a t i n g caused no more s w e l l i n g . pores a c c e s s i b l e t o m o l e c u l e s  The s w e l l i n g o f  25-560 ft d i a m e t e r  with  b e a t i n g i n c r e a s e d 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 p u l p .  As w i t h spruce wood, t h e s u l p h i t e p u l p  always c o n t a i n e d more water. With t h e e x c e p t i o n o f t h e 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 o b t a i n e d from a beaten p u l p were s w o l l e n t o t h e same e x t e n t .  The f i n e s  f r a c t i o n was s w o l l e n t o a much g r e a t e r e x t e n t .  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 a d s o r p t i o n  results  (16,54) as t o t h e e f f e c t o f b e 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 t o  water s w o l l e n c e l l o p h a n e , t e x t i l e r a y o n and super t i r e c o r d by Stone e t a l ( 7 4 ) .  The shape o f t h e pore volume d i s -  t r i b u t i o n i s v e r y s i m i l a r t o t h a t found f o r wood p u l p .  In  the n e v e r d r i e d s t a t e , t h e maximum pore s i z e s were about 200, 100 and 50 ft w i t h median pore s i z e s a p p r o x i m a t e l y 12 ft r e s p e c t i v e l y . reswelling.  40, 25 and  S m a l l e r v a l u e s were o b t a i n e d a f t e r d r y i n g and  The u n d r i e d c e l l o p h a n e  c o n t a i n e d about t w i c e  the water i n a c c e s s i b l e to large molecules as did wo o d p u l p  .  Textile  rayon had about t h e same i n a c c e s s i b l e volume as wood p u l p and super t i r e c o r d had c o n s i d e r a b l y  less.  -59III  - I N T E R F I B R E BONDING AND  I f one  s t u d i e s a water  MEASUREMENT OF  slurry  BONDED  of p u l p f i b r e s  p o s s i b l e t o d i s c e r n the s e p a r a t e i n d i v i d u a l  AREA  i t Is  pulp f i b r e s .  In  the paper making p r o c e s s , s l u r r i e s o f p u l p f i b r e s are d r a i n e d on a f i n e s c r e e n t o remove most o f the w a t e r , and the r e s u l t i n g web  i s a i r dried  t o produce'a c o h e s i v e sheet o f paper.  The  p h y s i c a l p r o p e r t i e s o f t h i s sheet are dependent on what ment the p u l p f i b r e s may  I f one  individual  s t i l l be d i s c e r n e d , but they are  s t u d i e s the sheet o f  a t t a c h e d t o the mass o f the' s h e e t . due p a r t l y  i s attributed  paper,  The attachment  t o f i b r e and f i b r i l entanglement,  s t r e n g t h o f attachment  now  i s probably  but most of the  to f i b r e - t o - f i b r e  M a r r i n a n and Mann (75) used d e u t e r a t i o n and red  treat-  have r e c e i v e d and what a d d i t i v e s t h e r e  are p r e s e n t i f any. f i b r e s may  wet  bonds.' infra-  s p e c t r o s c o p y t o show t h a t a l l the OH groups i n c r y s t a l l i n e  r e g i o n s o f r e g e n e r a t e d and b a c t e r i a l bonded. (The i n t e r a c t i o n  celluloses  between c e l l u l o s e  a l l o w s a b s o r p t i o n s due t o s t r e t c h i n g  are hydrogen  and heavy  water  o f OH groups i n  c r y s t a l l i n e and amorphous r e g i o n s t o 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 t o s e p a r a t e the • a b s o r p t i o n s due t o s e p a r a t e f i b r e s ) . Corte et a l (76) u s i n g an e x p e r i m e n t a l  procedure  of s t e p w i s e d e u t e r a t i o n have shown t h a t the m e c h a n i c a l s t r e n g t h of paper i s caused by hydrogen bonds between the The  fibres.  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  y e a r s and t h e e x a c t n a t u r e o f the f o r m a t i o n o f t h e s e 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 t h a t  -60tho  actual intorfibre  (76,77).  Thus  the i n t e r f i b r e  same f o r c e s t h a t irreversibile iz  bondo a r e due t o h y d r o g e n  cause  bonding  i s d r i e d from  bonding  bonding  i s dependent  t h e c o l l a p s e o f p o r e s and o f some l a m e l l a e  i n a single fibre  of i n t e r f i b r e  paper. light and  bonds, a r a t h e r  Some o f . t h e s e  light  commonly  used.  (90).  s c a t t e r i n g and gas a d s o r p t i o n  Measurement  o f t h e bonded a r e a  i s t h e o n l y method w h i c h g i v e s  bonded a r e a .  However t h i s  actual  contact  two  surfaces  one  half  (remember t h a t  and s u r f a c e s  to  determine  unbonded solvent  surface  of the pulp  freeze drying surface  give  prevent  values  bended  pulp  i s high  light  are around than  used  yields  fibres.  and s p r a y  between 4ft) o f  approximately  ( i . e . about  an a r e a  Methods drying  value but f o r the such as  of dilute  sus-  o f a m a t e r i a l which w i l l not Solvent  that  the complete  the I n d i v i d u a l f i b r e s  lengths  and  reading of  distinguish  one must h a v e a v a l u e  have been t r i e d .  probably  techniques of  area  these  have b e e n t h e most  a direct  by l e s s  Gas a d s o r p t i o n  on a c l e a n  h y d r o g e n bond drying  of the  t h e bonded a r e a ,  exchange,  pensions  separated  of the wavelength  18OO ft s e p a r a t i o n ) .  cannot  H bond  Of  by p o l a r i z e d l i g h t  a microscope  technique  (87-89)  microscopy  conductivity  of  (12, 78-8D);  methods a r e : gas a d s o r p t i o n  current .electrical  methods,  t o measure t h e  fundamental property  scattering.(79-86), p o l a r i z e d l i g h t  direct  when  water.  A number o f methods h a v e b e e n d e v i s e d area  on t h e  exchange  are too high closing  and t h u s  by t h e amount  as  and f r e e z e these  of the pore  the surface of surface  area  structures o f t h e un-  i n the pores  which  -61-  w o u l d h a v e c o l l a p s e d on d r y i n g . suspension, estimates  w h i l e not i d e a l ,  Spray d r y i n g o f a  should y i e l d  o f t h e unbonded a r e a .  dilute  reasonable  Of c o u r s e ,  inherent 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 t h e a s s u m p t i o n t h a t t h e external specific  s u r f a c e i s n o t 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 that occur technique  of determining  extrapolate the when p l o t t e d is  polarized convert  Young's m o d u l u s o r t e n s i l e  techniques  light  specific  assumptions.  This Light  method  scattering  have t h e r e s o l u t i o n p r o b l e m o f t h e  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 scattering coefficients  to areas.  conductivity also requires a  These c a l i b r a t i o n c u r v e s  adsorption data.  i s to  str'ength t o zero  a g a i n s t the sample's s u r f a c e a r e a .  current e l e c t r i c a l curve.  Another  an "unbonded" s u r f a c e a r e a  fraught with possible faulty  measurement  gas  i n a paper sheet.  o f bonded areas  measurement  of area.  The  to direct  calibration  are u s u a l l y determined  Thus, except  measurement  curve  f o r microscopic  from  techniques,  i s d e p e n d e n t on a g a s a d s o r p t i o n  -62IV - BACKGROUND THEORY A - The B. E. T. E q u a t i o n and S u r f a c e  Area  1938, B r u n a u e r , Emmett and T e l l e r (91) proposed a  In  method o f measuring s p e c i f i c s u r f a c e areas from vapour a d s o r p t i o n isotherms.  T h i s method has s i n c e become almost a s t a n d a r d f o r  m e a s u r i n g s u r f a c e areas o f 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 o f t h e e q u a t i o n was based on a k i n e t i c approach t o a d s o r p t i o n . t i s t i c a l mechanical same e q u a t i o n The  x(p  By assuming t h e same model, a s t a -  d e r i v a t i o n has been shown t o produce t h e  (92). B.E.T. E q u a t i o n i n i t s most common w o r k i n g  o  - P)  c - 1 \x c / \p^  (3)  Thus when p / x ( p - p ) i s p l o t t e d a g a i n s t p/p > a s t r a i g h t Q  form i s :  o  line  s h o u l d r e s u l t w i t h s l o p e = ( c - l ) / x c and i n t e r c e p t = I/x c. m m Thus knowledge o f t h e s l o p e and i n t e r c e p t a l l o w s c a l c u l a t i o n o f the monolayer volume, x^, and t h e v a l u e o f t h e c o n s t a n t , c. G e n e r a l l y t h e B.E.T. e q u a t i o n 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 p r e s s u r e range o f 0.05 - 0.30, however, t h e r e a r e cases  i n w h i c h t h e B.E.T. p l o t b e g i n s t o d e p a r t  when t h e r e l a t i v e p r e s s u r e exceeds 0.1 The criticisms. uniform  from l i n e a r i t y  (93).  B.E.T. e q u a t i o n has been s u b j e c t e d t o a number o f The model assumes t h e s u r f a c e i s e n e r g e t i c a l l y  ( i . e . a l l adsorption s i t e s are exactly equivalent)  but t h e r e i s . e v i d e n c e (94-101) t h a t t h e s u r f a c e s o f most s o l i d s  a r e h e t r o g e n e o u s i n an e n e r g e t i c s e n s e . neglects l a t e r a l adsorbed  layer  The  B.E.T. m o d e l  i n t e r a c t i o n s between m o l e c u l e s  (20).  Moreover, the n e g l e c t of  within  the  lateral  i n t e r a c t i o n s i s at v a r i a n c e w i t h the p o s t u l a t e t h a t the of a d s o r p t i o n f o r the second to the l a t e n t heat ( 1 0 2 , 103)  and  succeeding  of condensation.  I t has  i f a l l l a y e r s a f t e r the f i r s t  heat  layers i s equal been  questioned  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 . The  value x  m  obtained from the a p p l i c a t i o n of  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 o f  adsorbate  r e q u i r e d to cover the s u r f a c e w i t h a monomolecular The  specific  c o n f r o n t e d w i t h the dilemma: s e c t i o n a l area?  Emmett and  by t h e  of the adsorbate  this  Thus one  Brunauer  (104)  calculated  molecules  i n the bulk l i q u i d  from  or s o l i d  the  the form  equation: A  (4)  m  Where t h e v a l u e o f / t h e p a c k i n g f a c t o r , d e p e n d s on number o f n e a r e s t n e i g h b o u r s .  The  packing factor  the value,  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  in-the bulk l i q u i d  s i x on t h e p l a n e , i s u s u a l l y u s e d .  Emmett and  c a l c u l a t e d a v a l u e o f 16.2 has  is  what i s t h e m o l e c u l a r c r o s s -  c r o s s - g e c t i o n a l area of the adsorbate density  layer.  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  v a l u e by t h e 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 .  the  and  Brunauer  s q ft p e r n i t r o g e n m o l e c u l e  become somewhat o f a s t a n d a r d v a l u e , w i t h t h e  and  this  molecular  -64c r o s s - s e c t i o n a l areas of other adsorbates  a d j u s t e d t o 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) t h a t f o r some s o l i d s , t h e v a l u e o f argon be used as a s t a n d a r d 2  w i t h a coverage o f 13-7 ft p e r m o l e c u l e and t h e v a l u e s o f n i t r o g e n and o t h e r a d s o r b a t e s r e a s o n i n g behind  be a d j u s t e d a c c o r d i n g l y .  The  t h i s s u g g e s t i o n was t h a t f o r a d s o r p t i o n 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 nitrogen  molecule quadrupoles with the e l e c t r i c f i e l d of the s u r f a c e . Argon m o l e c u l e s a r e not s u b j e c t e d t o t h e s e a d d i t i o n a l i n t e r actions.  L i v i n g s t o n (106) and Kodera and O n i s h i (107)  suggested u s i n g  values  o f 15.4 and 14.2 ft / m o l e c u l e r e -  s p e c t i v e l y as t h e a r e a covered  per nitrogen  molecule.  Gregg and S i n g (20) have w r i t t e n an e x t e n s i v e of e x p e r i m e n t a l  work on t h e d e t e r m i n a t i o n  review  o f s u r f a c e a r e a by  the B.E.T. e q u a t i o n u s i n g a n i t r o g e n 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 o f 16.2 ft .  They c o n c l u d e d  that the surface area of a  sample as c a l c u l a t e d from t h e n i t r o g e n a d s o r p t i o n u s u a l l y agrees t o w i t h i n 20 p e r c e n t  Isotherm  and o f t e n l e s s w i t h  a r e a s c a l c u l a t e d from p a r t i c l e geometry.  surface  However, some problems  do e x i s t , P i e r c e and Ewing (108) have o b t a i n e d e v i d e n c e t h a t i n d i c a t e s t h e a d s o r p t i o n o f n i t r o g e n on g r a p h i t e i s l o c a l i z e d and  covers  f o u r u n i t hexagons o f g r a p h i t e s u r f a c e , t h u s  an e f f e c t i v e a r e a o f about 20 ft p e r m o l e c u l e .  having  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 error.  T h i s w i l l be d i s c u s s e d 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 t h a t o t h e r a d s o r b a t e s  d i d not  -65-  have t h e same v a l u e f o r 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 f o r a l l m a t e r i a l s i f t h e measured s u r f a c e a r e a was f o r c e d t o agree w i t h t h e argon v a l u e s . t a b l e 13.  T h e i r r e s u l t s a r e shown  in  U s i n g n i t r o g e n as a b a s e , Gregg and S i n g (20)  and D a v i s e t a l (109) found a s i m i l a r r e s u l t f o r o t h e r adsorbates. Table 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 Various Materials. A f o r various adsorbates, K —m  Adsorbent  N  2  at  -195°c  Ar a t  Benzene a t  -195°c  20°c  G r a p h i t i z e d carbon b l a c k s  16.2  13.7  40  Hydroxylated s i l i c a s  13-6  13.7  41  Dehydroxylated  14.8  13.7  silicas  * Table 2 o f r e f e r e n c e (105)  c  -66B - Most Common P o r e S i z e a n d A d s o r b a t e M o l e c u l e The  pore s i z e w i t h t h e l a r g e s t volume o f p o r e s i s  c a l l e d t h e most common p o r e s i z e . s t u d i e s on s o l v e n t e x c h a n g e pore s i z e  In nitrogen  1 9ftr a d i u s i f a c y l i n d r i c a l  i s a s s u m e d , 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 p o r e shape  i s assumed.  d r a w i n g s h o w i n g t h e s e two p o s s i b l e relative  adsorption  d r i e d c e l l u l o s e , t h e most common  i s f o u n d t o be a b o u t  p o r e shape  Size  F i g u r e 14 i s a s c a l e  shapes  o f pores and t h e  s i z e o f t h e adsorbed n i t r o g e n molecules.  ness o f a monolayer  The t h i c k -  i s shown . i f one assumes t h e hexagonal.;  p a c k i n g m o d e l o f L i p p e n s , L i n s e n a n d de B o e r shown i s t h e s t a t i s t i c a l  (110).  t h i c k n e s s o f t h e adsorbed  m o l e c u l e s when t h e p o r e h a s j u s t  Also nitrogen  emptied and t h e system i s  a t 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 t h e  pores, which are c e l l u l o s e molecules, are o f course not f l a t and c o n t i n u o u s a s i n d i c a t e d b u t a r e c o m p r i s e d o f atoms o f a s i z e commensurate w i t h t h a t i n d i c a t e d This figure emphatically problem o f assuming o f t h i s magnitude  f o r the nitrogen molecules.  shows t h e s i g n i f i c a n c e o f t h e  continuum b u l k l i q u i d p r o p e r t i e s i n pores  where t h e d i m e n s i o n s o f t h e a d s o r b e d  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 t h e pore d i m e n s i o n s .  Some c o n f u s i o n a s t o t h e m e a n i n g . o f has b e e n f o u n d .  Throughout  mole^-  various  terms  t h i s w o r k , maan o r m e d i a n p o r e  s i z e i m p l i e s t h e pore s i z e a t w h i c h h a l f t h e pore volume i s c o n t a i n e d i n s m a l l e r p o r e s and h a l f t h e - p o r e volume i n l a r g e r pores.  The most common p o r e s i z e i s t h e p o r e s i z e w i t h t h e  l a r g e s t volume o f p o r e s .  -67-  FI6URE 1 4 . RELATIVE SIZES OF MOST COMMON PORE SIZE AND ADSORBED NITROGEN MOLECULES.  PARALLEL  SIDED  FISSURE SHAPED PORE  25 A* WALL SEPARATION  LIMIT OF STATISTICAL MONOLAYER THICKNESS  LIMIT OF NUMBER OF STATISTICAL MULTILAYER COVERAGE AT EQUILIBRIUM RELATIVE PRESSURE.  \ CYLINDRICAL  I i  PORE  19 A* RADIUS.  \  i f f \  BULK  I  l  LIQUID  PROPERTIES  ASSUMED  r  -68C - Determining  P o r e S i z e by t h e K e l v i n  The K e l v i n e q u a t i o n ,  Equation  w h i c h i s t h e b a s i s o f many o f  t h e methods o f c a l c u l a t i n g p o r e s i z e d i s t r i b u t i o n s therm data W'.T.  The K e l v i n e q u a t i o n —dv dS  _ =  V  Y  1  RT l n ( p / p  The e q u a t i o n  )  i n 1871  (115).  as p r e s e n t l y used i s : c o s f,  (/5\) c  describes the e q u i l i b r i u m condition  between t h e vapour p r e s s u r e s i z e o f pore which w i l l  o f an a d s o r b a t e and t h e l a r g e s t  be f i l l e d  t o use the e q u a t i o n ,  with l i q u i d  i t i s necessary  to the surface t e n s i o n , Y , the angle  The u s u a l method o f a s s i g n i n g t h e s e  adsorbate. to assign  values  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 ,  the  iso-  ( 4 6 - 4 8 , 1 1 1 - 1 1 4 ) , was d e r i v e d i n a p a p e r by  Thompson ( L o r d K e l v i n ) p u b l i s h e d  In order  from  V ( o r t h e d e n s i t y , ).  values  i s t o assume  a d s o r b a t e p e r f e c t l y wets t h e adsorbent s u r f a c e  that  (i.e.cf>=  0)  and-that the bulk  l i q u i d values  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 p o r e s h a p e 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 . a r e u s u a l l y assumed. the  Cylindrical  pores  The p h y s i c a l p o r e s i z e i s l a r g e r t h a n  K e l v i n p o r e s i z e by v i r t u e o f t h e l a y e r s o f a d s o r b a t e  a d s o r b e d on t h e s u r f a c e by t h e 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)  differ.  The u s e o f a K e l v i n e q u a t i o n mining  method f o r d e t e r -  t h e p o r e s i z e d i s t r i b u t i o n o f an a d s o r b e n t f r o m a n  :  -69i 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  criticisms:  (a)  The v a l i d i t y  of the K e l v i n equation  itself.  (b)  The a s s e s s m e n t o f t h e t h i c k n e s s o f t h e r e s i d u a l adsorbed f i l m .  (c)  The a s s u m p t i o n o f t h e s h a p e o f t h e p o r e s For t h e convex s u r f a c e o f d r o p l e t s t h e K e l v i n  equation  has been v e r i f i e d  microns f o r water (118) .  of curvature  (116) d i b u t y l p h t h a l a t e  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  a micron I n diameter (119) .  for radii  of several  (117) a n d m e r c u r y  f o rdroplets less  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  acid  However, f o r t h e concave s u r f a c e o f a l i q u i d  in a capillary  o f t h e o r d e r o f one m i c r o n d i a m e t e r ,  perimental results are considerably different c a l c u l a t e d by t h e K e l v i n e q u a t i o n . mental r e s u l t s o f others  Shereshefsky  (123)  meniscus  the ex-  from t h e values  Considering the experi-  (120-122) a s w e l l a s t h e i r  e x p 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  than  own  m a t e r i a l s , Folman and  concluded:  "The r e s u l t s o f t h e s e m e a s u r e m e n t s show t h a t t h e K e l v i n e q u a t i o n c a n n o t be a p p l i e d i n e s t i m a t i n g v a p o u r 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 c a n i t be a p p l i e d i n e s t i m a t i n g p o r e r a d i i a t g i v e n v a p o u r p r e s s u r e s a s 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 t i m e s g r e a t e r t h a n t h e v a l u e calculated with t h i s equation. Moreover, the e f f e c t d i f f e r s i n m a g n i t u d e w i t h t h e n a t u r e o f t h e 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 f o u n d 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 t h e r e s u l t s f o r water r e p o r t e d i n t h e p r e c e d i n g p a p e r (122) show t h a t t h e e f f e c t for the l a t t e r i s s t i l l greater. T h i s e f f e c t seems t o change w i t h t h e 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 . "  -70-  Experimental 1-10  data  for capillaries  m i c r o n s d i a m e t e r show no  tension  (124)  (water  and  (125,  or d e n s i t y (127)  work, F e d y a k i n  significant 126).  found the  ft  (0.02  r a d i u s of the  Also, theoretical  and  (129)  curvature  on  s u r f a c e t e n s i o n be  slight  1 m i c r o n but  become a p p r e c i a b l e  for radii  increase with decreasing has  shown t h e  2r-20.  validity  o f a few  radius the  effect  by  of  in capillaries  Deryagin  o f 100 (38)  ft  of the K e l v i n equation  of  and  recently  capillaries  a d e n s i t y o f 1.3  angstroms i s very  liquids  d e p e n d e n t on  e x i s t e n c e of water i n quartz  m i c r o n s d i a m e t e r w h i c h has  Thus, the order  size.  recent  tubes of  r e q u i r e t h a t the  of  surface  considerations  T o l m a n (128)  Hill  changes i n  surface t e n s i o n of  m i c r o n s ) d i a m e t e r was  tube.  order  However, i n  benzene) measured i n c a p i l l a r y  down t o 200  of the  of  g./ml.  i n pores of  d o u b t f u l even f o r  the  non-polar  adsorbates. To  show t h e p o s s i b l e e f f e c t o f e r r o r s i n t h e  physical property  parameters, the  cumulative  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 t h e  P i e r c e method  f r o m a 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 isotherm.  The  T  =  K e l v i n equation  r. K  The  values  =  — 2M  -  ;  RTp  was  s i m i l a r t o t h a t u s e d by r e s u l t s of these  .,. coscj)  Y  ln(p/p )  c a l c u l a t i o n s are  =  dis-  (48)  desorption  t o the  form:  - 4.14  K  ,c\  (6)  ln(p/p )  o  S p e n c e r and  w h i c h show t o what e x t e n t  nitrogen  rearranged  1  o f K were v a r i e d f r o m 0.5  pore volume  Q  t o 2.0 Fereday  i n a manner (130).  shown i n f i g u r e s 15  t h e pore volume d i s t r i b u t i o n  The and  16  depends  CUMULATIVE  8  PORE VOLUME  (ml* N  2  (8.T.P.))  8  ro o o CO  j> Oi 2 O O ro  •  03  ro  ro  H  6  ro o ro o  CO CO c  ay ro  =8  8  o z  PO  >  5>  ro  ro o  —  -1  «  a) ro > r~ rro < z o o r* r CO c o ro ro •o z o C oO -< -nO H CO C 3) o CO CD > r c30' C ro H O 2 Z 30 X> o ro o ro H r ro a> 30  z  CO  -73-  on the v a l u e s The  of the p h y s i c a l p r o p e r t i e s of the  number of monomolecular l a y e r s on the  i s d e t e r m i n e d from i s o t h e r m s  on nonporous s o l i d s  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 m o l e c u l a r s e c t i o n VI-G).  adsorbate.  This estimate  surface  of level -  of the number of  see  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 a d j a c e n t  pore w a l l s may  i n c r e a s e the  ad-  s o r p t i o n o f the a d s o r b a t e over t h a t p r e d i c t e d from a porous a d s o r p t i o n i s o t h e r m  (105).  non-  Even w i t h a p r e d i c t e d  number o f 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. the l i t e r a t u r e has  A search  r e v e a l e d c o n s i d e r a t i o n s o n l y 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 . L i p p e n s et a l assumed a h e x a g o n a l p a c k i n g  and  3.54 ft per monolayer. 4.3 ft per monolayer.  (110)  a normal b u l k 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 S h u l l (47)  of  determined a t h i c k n e s s  of  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  t h a n the c l o s e r hexagonal p a c k i n g .  Both workers assumed  a l l monolayers are of the same e s t i m a t e d 17 shows the d i f f e r e n c e i n the c u m u l a t i v e t r i b u t i o n w i t h the two models.  The  thickness.  Figure  pore volume d i s -  value assigned  t h i c k n e s s of a monolayer of adsorbed a r g o n , 3-28  to  ft,  the  was  d e t e r m i n e d u s i n g the L i p p e n s et a l model and e q u a t i o n s the e x t r a p o l a t e d b u l k l i q u i d argon d e n s i t y assumed t o 1.452  of  with be  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 t o  geometry assumed f o r the p o r e . pores r ^ i n e q u a t i o n  I 1  the  For example, i n c y l i n d r i c a l  6 i s the c y l i n d e r r a d i u s , but  for  180  60-1  1 1  20  1  25 30 DISTANCE BETWEEN  1  i  i  i  40 50 60 70 WALLS O F FISSURES (A*)  i  80  i  i  90 100  -75-  p a r a l l e l s i d e d f i s s u r e s r, i s x , t h e pore w i d t h .  r,  k  k  f o r o t h e r g e o m e t r i e s has o t h e r v a l u e s (page 139 r e f e r e n c e 2 0 ) . C o n s i d e r i n g t h e p r o b a b l e i r r e g u l a r i t y o f t h e shape o f pores o c c u r r i n g i n an a d s o r b e n t , t h e c h o i c e o f t h e form o f t h e K e l v i n e q u a t i o n must depend on o t h e r i n f o r m a t i o n t h a n on the s t r u c t u r e o f t h e m a t e r i a l i f ' i t i s t o have much s i g nificance. I n s p i t e o f t h e s e r i o u s drawbacks  to the K e l v i n  e q u a t i o n , i t remains t h e o n l y p r a c t i c a l means o f 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 t h e range o f  1 5 - 1 5 0 ft.  D - D u b i n i n Pore S i z e Dubinin  Classifications  (131-133)  as a r e s u l t o f h i s work w i t h  porous c a r b o n s , grouped pores i n t o t h r e e c l a s s i f i c a t i o n s : macropores, I n t e r m e d i a t e o r t r a n s i t i o n a l p o r e s and m i c r o pores.  The s i z e r a n g e , a d s o r p t i o n c h a r a c t e r i s t i c s and  methods o f e x a m i n a t i o n o f each pore c l a s s a r e b r i e f l y  dis-  cussed below. 1. Macropores: The e f f e c t i v e r a d i i o f t h e l a r g e s t v a r i e t y o f adsorbent p o r e s , macropores, exceed  1000-2000  ft.  Under o r d i n a r y c o n d i t i o n s o f a d s o r p t i o n experiments the macropore of  volume cannot be f i l l e d as a r e s u l t  c a p i l l a r y c o n d e n s a t i o n o f vapours because o f t h e  d i f f i c u l t y of achieving equilibrium f o r r e l a t i v e p r e s s u r e s near u n i t y and because t h e a d s o r p t i o n p r o cess has an e x t r e m e l y slow r a t e under t h e s e c o n d i t i o n s . Thus, macropores  p l a y t h e p a r t o f t r a n s p o r t pores and  make t h e i n t e r n a l p a r t s o f g r a i n s o r p e l l e t s o f adsorbents  e a s i l y a c c e s s i b l e f o r t h e adsorbed  molecules. I n f o r m a t i o n c o n c e r n i n g t h e volume d i s t r i b u t i o n o f t h e macropores can be o b t a i n e d by measuring t h e volume o f mercury which can be f o r c e d i n t o t h e pores under v a r i o u s p r e s s u r e s . Intermediate The  o r T r a n s i t i o n a l Pores  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 a r e much l a r g e r than t h e s i z e o f t h e molecules pore  adsorbed.  The s u r f a c e o f an i n t e r m e d i a t e  has monomolecular l a y e r s o f adsorbate  on i t d u r i n g t h e a d s o r p t i o n p r o c e s s . o f i n t e r m e d i a t e pores by t h e c a p i l l a r y  formed  The f i l l i n g condensation  mechanism t a k e s p l a c e w i t h i n t h e range o f 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 c o n s i d e r t h a t t h e e f f e c t i v e r a d i i o f i n t e r m e d i a t e pores l i e between 15-20 ft and 1000-2000 ft. The lower boundary o f 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 o f t h e K e l v i n e q u a t i o n , as shown by D u b i n i n e t a l (134, 135) on t h e b a s i s o f a thermodynamic a n a l y s i s o f e x p e r i m e n t a l d a t a on a d s o r p t i o n and  c a p i l l a r y condensation Dubinin  o f vapours.  (131) d i s c u s s e s means o f e x a m i n i n g t h e  d i s t r i b u t i o n and volume o f these i n t e r m e d i a t e o r t r a n s i t i o n a l pores.  The method o f f o r c i n g mercury  i n t o pores under p r e s s u r e can be u s e d , however  -77-  a d s o r p t i o n methods are u s u a l l y  utilized.  In the r e g 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 the s o r p t i o n and d e s o r p t i o n 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  hysteresis loop.  i n the t r a n s i t i o n a l pores t h a t c a p i l l a r y s a t i o n of a d s o r b a t e vapour t a k e s p l a c e . between adsorbed f i l m s  It is  condenThe  space  i n these pores i s l a r g e  enough, compared w i t h the dimensions of an a d s o r b a t e m o l e c u l e , f o r the i d e a of a concave l i q u i d i n such pores t o have p h y s i c a l  meniscus  significance.  The s p e c i f i c s u r f a c e a r e a of t r a n s i t i o n a l  pores  can be a s s e s s e d from the s u r f a c e a r e a o f the adsorbed f i l m c o v e r i n g the pore w a l l s at the b e g i n n i n g of c a p i l l a r y condensation.  C o m p l e t i o n of the c a p i l l a r y  c o n d e n s a t i o n p r o c e s s , when the r e l a t i v e p r e s s u r e becomes e q u a l t o u n i t y , l e a d s t o the f i l l i n g o f the entire  volume of t r a n s i t i o n a l pores w i t h  condensed  vapour and c o n s e q u e n t l y t o the d i s a p p e a r a n c e of the s u r f a c e of the adsorbed  films.  As the t r a n s i t i o n a l pores are l a r g e r by at one o r d e r of magnitude  least  t h a n adsorbed m o l e c u l e s o f  vapour, the t h i c k n e s s of the m u l t i m o l e c u l a r f i l m s . o n the  s u r f a c e , two or t h r e e monolayers  sufficent  thick,  i s not  t o d i m i n i s h the d i a m e t e r s e r i o u s l y .  There  c a n , t h e r e f o r e , be s c a r c e l y any doubt as t o the r e a l i t y of the p r o c e s s o f c a p i l l a r y c o n d e n s a t i o n o f vapour i n such p o r e s , s t i l l molecular dimensions.  so l a r g e i n comparison t o  -783 - Micropores For  the  micropores, range  from  angle  X-ray  to  their  the  smallest the  5-6 ft t o  13-14  scattering  molecules  mary  effective  sizes,  For  ft,  are  as  method  adsorbent within  s h o w n by  (136).  are  of  with  such  With  f a r as  lose  pores  coverage  from  their  to  case,  s u r f a c e of nonporous  Adsorption  on  or macropores  microporous  not  a  the  surface of the micropores  the  custo-  of  a  signi-  i s concerned,  adsorption occurring  pores  on  and  a d s o r p t i o n space. of microporous  The  the  surface of  i n the  limiting  adsorbents.  adsorbents  but  the  concept  adsorbents  the  differs  involves  successive formation of adsorption layers  their area  size  physical  i t s mechanism  intermediate the  small regard  and  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  on  the  the  similar  small  layer-by-layer  surface area As  radically  pores,  adsorbed.  concepts of  ficance.  of  radii  micropores  adsorbents  micropore  variety  loses  filling of  on  of  a surface  i t s physical  significance. A  characteristic  microporous the  feature  adsorbents  a d s o r p t i o n energy  tion  potentials  corresponding pored  J  chemical  is a and  o f a d s o r p t i o n on  substantial  consequently, the  i n micropores  as  values for large  or nonporous nature.  curves  compared  pored  adsorbents  The  increase  of  a  in  adsorp-  to  the  intermediate similar  of d i f f e r e n t i a l  heats  -79of adsorption of the adsorbate and  non-porous adsorbent  increase  should  i n adsorption energies  porous case over An  on a m i c r o p o r o u s show a  significant  f o r the micro-  t h e non-porous  case.  i n c r e a s e i n a d s o r p t i o n energy i n micropores  leads to a considerable increase i n the value of 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 pressures. values  Table  14 l i s t s  relative  adsorption  o f b e n z e n e a t 20°C f o r n o n p o r o u s  b l a c k Spheron-6 w i t h a s u r f a c e a r e a  carbon  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 a t 950°C, a n d f o r two s p e c i m e n s o f a c t i v e c a r b o n s AC-1 a n d AC-2 a c t i v a t e d a t 950°C. a n d p o s s e s s i n g structures.  different  microporous  The amounts a d s o r b e d f o r e a c h  a t 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 a d o p t e d as a r b i t r a r y pressure  units.  approximately  p/p =0.175 a r e Q  For carbon black  corresponds  corresponds  filling  to the p r a c t i c a l  of micropores  experimental  data  completion  as a r e s u l t  the values  passing  from nonporous  of the  f o r AC-2 w i t h s m a l l e r  The  how  of vapor a d s o r p t i o n Increase  In  ( o r intermediate pored ) t o  microporous carbonaceous adsorbents,  * value  carbons,  of adsorption.  o f t a b l e 14 i l l u s t r a t e  greatly  this  to the formation  of a complete monolayer, whereas f o r a c t i v e it  adsorbent  particularly  micropores.  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 B e n z e n e a t 20°0 on C a r b o n B l a c k and A c t i v e C a r b o n s Carbon B l a c k  Active  0  Carbons  AC-1  AC-2  1 v 10"  5  0.02  0.12  0.44  1 x 10"  4  0.06  0.16  0.57  1 x 10"  3  0.14  0.46  0.73  1 x 10"  2  0.33  0.71  0-87  1 x 10"  1  0.81  0.92  0.96  1.00  1.00  1.00  0.175  The  p h y s i c a l properties of micropores  best determined  by l o w a n g l e X - r a y  are  scattering  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 If  a solid  of Micropores  contains micropores  ( i . e . pores  which  h a v e 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 a d sorptive behavior w i l l macroporous s o l i d s .  be o t h e r t h a n t h a t  In p a r t i c u l a r , the p o t e n t i a l  from o p p o s i t e w a l l s of the pore w i l l  * From R e f e r e n c e  of non-porous  (132)  or  fields  o v e r l a p so t h a t  the  -81attractive  forces  increased face.  a c t i n g on a d s o r b a t e  i n comparison  The a d s o r p t i o n  torted  increased  total  discussed  above  the  cavities  onto  o r pores  estimate liquid  calculated area  measured  isotherms  very  micropores, o r more second  diffraction  studied  carefully  where  surface  (132)  samples o f  crystals of of the  were  This  deter-  allowed  o f t h e samples.  good, l i n e a r  an  The  a monolayer as  for this  computed  t h epore  diffraction.  surface  volume a v a i l a b l e  However, t h e a d s o r p t i o n B.E.T. p l o t s .  In larger  i t i s p h y s i c a l l y p o s s i b l e t o adsorb two  layers, theincreased and p o s s i b l y higher  heat  layers  between t h e f i r s t  there  will  be no m o n o l a y e r p o i n t  along  t h ebranch  complete  molecules  will  filling  of adsorption obscures  and higher  o f the isotherm  analyses,  classical  crystals  t o form  adsorption  the  This  energy and  prepared  o f dehydrated  t o be l a r g e r t h a n  by X-ray  be d i s -  theadsorption of  measurements.  o f gas required  sur-  adsorption.  adsorption  i nthedehydrated  did yield  accordingly  be  IV-D-3  b y t h e B.E.T. m e t h o d  was f o u n d  on an open  . The shapes a n d d i m e n s i o n s  of thespecific  volume  will  as measured by D u b i n i n  i nsection  zeolites.  mined by X-ray  as  by i n c r e a s e d  a l u m i n o - s i l i c a t e framework  synthetic  will  (132,135,138)  and n i t r o g e n  present  o f an increased  adsorption  Dubinin water  isotherm  i nthedirection  phenomenon i s e v i d e n c e d  and  t o those  molecules  t h e changes i n  layers  used  o f t h epores with  be o c c u r r i n g .  (139).  on t h e i s o t h e r m normally  I n cases  methods o f c a l c u l a t i n g  In the  where  Thus,  and even  for  B.E.T.  adsorbate this  i s so,  t h emonolayer  capacity  -82will,  of course,  b r e a k down.  Some e v i d e n c e  b r e a k down o f c a l c u l a t i o n a l m e t h o d s has (140, The  141);  this  i s d i s c u s s e d by  most d r a m a t i c  saran  charcoal  (140)  be  of the p h y s i c a l s t r e n g t h of the  limit  (and  w h i c h i t i s p o s s i b l e t o use  3130 each  o f 7 s q . ft,  an a r e a  sample would have probable  i n view  This  lower  limit  equation  i s d e t e r m i n e d by  the  K e l v i n equation  s h o u l d be  Is  i s studying very  of a p p l i c a b i l i t y two  based  distribution  of  small  of the K e l v i n  circumstances.  ment t h a t a c o n c a v e l i q u i d m e n i s c u s be between the adsorbate  lower  h e n c e t h e p o r e s i z e ) down t o  f u n d a m e n t a l i m p o r t a n c e when one pores.  present  The  require-  i n the. space  l a y e r s on t h e p o r e w a l l s , and  no p o s s i b i l i t y  f i n e p o r e s by  to  sample.  methods o f c a l c u l a t i n g p o r e v o l u m e  on  (20).  q u e s t i o n of the p h y s i c a l b a s i s of the  r e l a t i v e pressure  latively  Sing  particular  a c c e s s i b l e t o t h e gas,' a phenomenon n o t  there  obtained  surface of  o f a l l c a r b o n atoms I n t h e  The  this  i s o t h e r m ) , h o w e v e r , as  c a r b o n atom o f g r a p h i t e o c c u p i e s nine-tenths  is a  with a specific  sq.m./g. ( c a l c u l a t e d f r o m an  been  G r e g g and  piece of evidence  for  of volume f i l l i n g  coalescence  of the  i n t h e a d s o r p t i o n p o t e n t i a l s due  to the  of the  adsorption  o p p o s i t e w a l l s o f t h e p o r e s as a r e s u l t  o f an  overlap  that re-  layers  increase from  adjacent  surfaces. The  idea of the  physical significance tween the  adsorption  n e s s o f a few  concave l i q u i d  meniscus l o s e s i t s  f o r f i n e pores i n which the l a y e r s i s only of the order  molecules.  In a c t u a l f a c t , the  space of the  bethick-  increase i n  the a d s o r p t i o n p o t e n t i a l s i n f i n e pores l e a d s t o a subs t a n t i a l i n c r e a s e i n the amount o f a d s o r p t i o n i n comparison w i t h t h a t found f o r nonporous a d s o r b e n t s .  As a r e s u l t , t h e  f i n e s t pores a r e f i l l e d w i t h a form o f l i q u e f i e d vapour caused by t h e c o a l e s c e n c e  of the adsorption l a y e r s during  the p r i m a r y a d s o r p t i o n p r o c e s s .  I n pores o f somewhat  l a r g e r s i z e s the o v e r l a p p i n g a d s o r p t i o n p o t e n t i a l f i e l d s  will  l e a d t o s i g n i f i c a n t d e v i a t i o n s from t h e K e l v i n e q u a t i o n . F - The D u b i n i n Theory of A d s o r p t i o n on Microporous In  the i n i t i a l stages o f development,  Solids  Dubinin's  ( 1 3 1 , 1 3 3 , 1 4 2 ) t h e o r y o f a d s o r p t i o n o f gases and vapours by microporous adsorbents  r e p r e s e n t e d an e x t e n s i o n of P o l a n y i ' s  p o t e n t i a l t h e o r y o f a d s o r p t i o n (143,144).  According to  P o l a n y i ' s t r e a t m e n t , t h e " a d s o r p t i o n space" i n the v i c i n i t y of a s o l i d s u r f a c e i s c h a r a c t e r i z e d by a s e r i e s o f e q u i p o t e n t i a l s u r f a c e s , ( i . e . s u r f a c e s o f t h e same a d s o r p t i o n potential).  The a d s o r p t i o n p o t e n t i a l , e,at t h e l i q u i d -  vapour i n t e r f a c e i s g i v e n by: (7)  e  and s i n c e by h y p o t h e s i s the adsorbate  i s i n l i q u i d form, t h e  volume o c c u p i e d by t h e adsorbed vapour can be expressed  w  x P  as :  (8)  -84-  As both W and e can be c a l c u l a t e d from an  experimental  i s o t h e r m , i t i s p o s s i b l e to. e v a l u a t e the e q u a t i o n of the characteristic W  =  curve. f(e)  (9)  P o l a n y i made no attempt t o d e r i v e an  expression  f o r the a d s o r p t i o n i s o t h e r m from the p o t e n t i a l D u b i n i n and co-workers ( 1 3 3 ,  142) have d e r i v e d such an  p r e s s i o n u s i n g the f o l l o w i n g arguments. p o t e n t i a l , which i s due between the adsorbent  theory.  The  adsorption  t o d i s p e r s i o n and p o l a r f o r c e s  and adsorbate  molecules  i s In-  dependent o f temperature but v a r i e s a c c o r d i n g to the of the adsorbate  ex-  as w e l l as the adsorbent.  nature  However, both  the- d i s p e r s i o n f o r c e and the p o l a r f o r c e are f u n c t i o n s o f the p o l a r i z a b i l i t y of the adsorbed m o l e c u l e . f o r two d i f f e r e n t  adsorbates  a d s o r p t i o n space, W,  Thus,  f i l l i n g the same volume o f  on a g i v e n a d s o r b e n t ,  the a d s o r p t i o n  potential  of one adsorbate  d i v i d e d by the a d s o r p t i o n  potential  o f the o t h e r w i l l be a c o n s t a n t independent of  the a d s o r p t i o n space f i l l e d .  T h i s c o n s t a n t 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 t a k e n as an  s t a n d a r d , by combining the c h a r a c t e r i s t i c  curve  arbitrary  (equation  9)  w i t h the a f f i n i t y c o e f f i c i e n t , a g e n e r a l e x p r e s s i o n f o r the characteristic  curve i s o b t a i n e d .  -85-  w =  (10)  0  \0  I n t h i s c a s e , ^e  /  the a d s o r p t i o n p o t e n t i a l o f the s t a n d a r d  s  0  adsorbate. D u b i n i n and h i s co-workers  assumed t h a t the volume  of the a d s o r p t i o n space c o u l d be e x p r e s s e d as a  Gaussian  f u n c t i o n o f the c o r r e s p o n d i n g a d s o r p t i o n p o t e n t i a l .  Thus  the form o f the g e n e r a l c h a r a c t e r i s t i c curve i s changed to: W  =  V . e mic  -k  (e_\  W  (11)  Where V mic . i s the t o t a l microporous ^  volume and k i s the  s t a n t c h a r a c t e r i s i n g the pore s i z e  con-  distribution.  By s u b s t i t u t i n g e q u a t i o n (7) and  (8) f o r W and e ,  and r e a r r a n g i n g , e q u a t i o n (11) becomes an e x p r e s s i o n f o r the adsorption.  x  =  U i U // /  pV mlc . e x p H r2 RT I n  —  T a k i n g the l o g a r i t h m of e q u a t i o n (12), y i e l d s the  (12)  working  Dubinin equation.  log x 1 0  =  log (V . p) 1 0  m  c  - K (log 2  1 0  /^  (13)  -86-  where: K  =  2.303^-(RT) B  (14)  2  2 Thus a p l o t  of l o g  1 0  ( x ) vs.  Ilog  1 0  |  should  —  y i e l d a s t r a i g h t l i n e of s l o p e D and i n t e r c e p t l o e , ( V . p). ^ 10 mic ' rt  &  D u b i n i n (133,139) has found e q u a t i o n (13) t o a p p l y over the range of r e l a t i v e p r e s s u r e s 1x10 number o f a d s o r b a t e s the adsorbent  t o 0.2  i n c l u d i n g n i t r o g e n i n those cases where  i s truly  microporous.  E x p e r i m e n t a l a d s o r p t i o n d a t a can be  substituted  d i r e c t l y i n t o e q u a t i o n (13) o n l y i f the adsorbent microporous  w i t h weakly  mediate) p o r o s i t y .  for a  developed t r a n s i t i o n a l  D u b i n i n (133)  i s highly  (or i n t e r -  s t a t e d t h a t i f the  s u r f a c e a r e a o f the t r a n s i t i o n a l p o r e s ,  specific  , a p p r e c i a b l y ex-  ceeds 50 sq.m./g., the e x p e r i m e n t a l v a l u e s of a d s o r p t i o n , : f o r each r e l a t i v e p r e s s u r e , p/p  Q  s h o u l d be c o r r e c t e d f o r adsorp-  t i o n on the s u r f a c e of the t r a n s i t i o n a l x  where  a  =  x  e  pores:  - a S, t  (15)  i s the v a l u e of 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  of the nonporous a d s o r b e n t , 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 D u b i n i n p l o t , l o g ^  5  °10  n n  ( V . p), mic '  r e p r e s e n t s the number of m o l e c u l e s r e q u i r e d t o f i l l porous volume, t h u s , the e q u a t i o n i s f r e e of the  the m i c r o -  assumption  t h a t the b u l k d e n s i t y 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 m i c r o p o r e s . p  However, some v a l u e must be a s s i g n e d t o  i f an e s t i m a t e o f t h e microporous  volume i s t o be ob-  tained. The weaknesses o f t h e a p p l i c a t i o n Theory t o c e l l u l o s e a)  of the Dubinin  apparently are:  The assumption  t h a t a Gaussian d i s t r i b u t i o n of the  corresponding adsorption p o t e n t i a l  would d e s c r i b e  the m i c r o p o r e volume d i s t r i b u t i o n when a p p a r e n t l y the pore s i z e d i s t r i b u t i o n including b)  i s o f a wide  range,  t h e m i c r o - and t r a n s i t i o n a l - pore  The t h e o r y assumes b u l k f i l l i n g but l a y e r  by l a y e r  filling  sizes.  of the micropores  of the t r a n s i t i o n a l  p o r e s , w i t h no a l l o w a n c e s 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 o f l a r g e a d s o r b a t e m o l e c u l e s  than  small adsorbate molecules w i l l f i t i n t o very s m a l l pores). G - The Kaganer Method f o r D e t e r m i n a t i o n o f t h e S u r f a c e Kaganer ( 1 4 5 , 1 4 6 ) m o d i f i e d t h e D u b i n i n t o o b t a i n a method f o r t h e c a l c u l a t i o n  Area  treatment  of s p e c i f i c surface.  He assumed t h a t t h e d i s t r i b u t i o n o f a d s o r p t i o n  potential  over t h e s i t e s on t h e s u r f a c e i s G a u s s i a n i n t y p e .  Dubinin  assumed t h a t t h e volume o f t h e a d s o r p t i o n space may be exp r e s s e d as a G a u s s i a n f u n c t i o n o f t h e c o r r e s p o n d i n g tion potential.  adsorp-  The Kaganer w o r k i n g e q u a t i o n i s :  (16)  -88Equation equation  (3.6)  ( e q u a t i o n 13)  is Identical and  a ' p l o t of l o g  should again give a s t r a i g h t ordinate axis  (where p - p  i n form w i t h 1 Q  x against  l i n e w i t h the  ) now  Dubinin's log^  intercept  on  such  (145,  146)  as n i t r o g e n , a r g o n  silica of x  and  g e l s , c h a r c o a l s and o b t a i n e d from  used isotherms  tained  from  aluminas  equation  (16)  t h e B.E.T. e q u a t i o n .  I 3 percent 148)  of adsorbates .  k r y p t o n on a d s o r b e n t s  m  between the v a l u e s .  t o compare t h e  He  found  Thus l i k e  regarded  the Kaganer e q u a t i o n ( e q u a t i o n 13)  are  g l a s s of  These workers  found  although  quite well.  study although at  ( e q u a t i o n 16)  be  present  as e s s e n t i a l l y . " ' e m p i r i c a l . and  so g e n e r a l i n f o r m  e i t h e r o f them c a n n o t represent.  workers  t h e D u b i n i n method, t h e Kaganer method  c e r t a i n l y worthy of f u r t h e r  t h e method must be  of  measuring  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 considered best agreed  ob-  agreement  °K w i t h p y r e x  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 .  as •  values  to the values of x . m  h a v e t e s t e d t h e K a g a n e r e q u a t i o n by  the data they  such  However, o t h e r  t h e a d s o r p t i o n o f n i t r o g e n a t -195  is  the  volume. Kaganer  (147,  the  equal to the l o g a r i t h m of  the monolayer c a p a c i t y r a t h e r than to the l o g a r i t h m of pore  Pp \ P~  the Dubinin  equation  that conformity  t a k e n as e v i d e n c e  Both  to  f o r the model  they  -89-  H - The Work o f H a r r i s and S i n g A paper by H a r r i s (149) compared an average pore r a d i u s , r^., d e t e r m i n e d by t h e K e l v i n e q u a t i o n w i t h t h e average pore r a d i u s as d e t e r m i n e d by t h e e q u a t i o n : ( G u r v i t c h mean pore radius).  g  o b  0.08  The a d s o r b e n t s used were t i t a n i a s and a l u m i n a s s p e c i a l l y p r e p a r e d w i t h v e r y 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 d e t e r m i n e d by H a r r i s (149) was d e t e r m i n e d from t h e p a r t i a l p r e s s u r e at t h e p o i n t of s t e e p e s t descent o f t h e d e s o r p t i o n i s o t h e r m .  Harris  (150) s t a t e s t h a t t h i s method has been shown t o compare f a v o u r a b l y w i t h t h e v a r i o u s pore s i z e d i s t r i b u t i o n t e c h n i q u e s f o r d e s o r p t i o n i s o t h e r m s i n which a l m o s t a l l desorption occurs  over a s m a l l p r e s s u r e range ( i . e . narrow  pore s i z e d i s t r i b u t i o n ) .  T h i s a s s u m p t i o n 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 o f 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 t o be 30-35 ft whereas  t h e most common  ( s t e e p e s t descent on t h e d e s o r p t i o n i s o t h e r m ) pore s i z e was found t o be i n t h e 18-20 ft range. H a r r i s (150) assumed t h a t monolayer occurred at p/p  Q  = 0.08.  coverage  He used t h i s method o f d e t e r m i n i n g  the  s u r f a c e a r e a , S, as he c l a i m s t h e B.E.T. e q u a t i o n does  not  a p p l y t o t h e m a t e r i a l s he s t u d i e d ( 1 5 1 ) .  He a l s o  -90-  calculated V (152)..  from the amount of gas adsorbed at p/p  Stone and S c a l l a n used p/p  = 0.9  =0.965 (35).  F i g u r e 18 shows the r e s u l t s o f t h i s  comparison.  From these r e s u l t s , H a r r i s c o n c l u d e s the K e l v i n e q u a t i o n f o r a n i t r o g e n i s o t h e r m i s not a p p l i c a b l e t o pores below about 18 ft r a d i u s , or a p p r o x i m a t e l y the upper s i z e l i m i t o f a m i c r o pore as d e f i n e d by D u b i n i n .  He a l s o c o n c l u d e s t h a t a l l  s m a l l e r pores i n d i c a t e a r a d i u s o f about 18  ft.  Thus i f  pores of l e s s t h a n 18 ft r a d i u s are p r e s e n t , they w i l l  appear  as 18 ft r a d i u s p o r e s . In h i s paper comparing the G u r v i t c h and K e l v i n . p o r e r a d i i , H a r r i s a l s o concludes t h a t the d e s o r p t i o n i n pores of 18 ft r a d i u s or l e s s appears t o be governed by a mechanism  :  dependent o n l y on the a d s o r b a t e and the t e m p e r a t u r e , and independent o f the pore s i z e of the adsorbent ( 1 4 9 ) .  He .  d i s c u s s e s the mechanism of d e s o r p t i o n and c o n c l u d e s ( 1 5 0 ) : " t h a t at a p r e s s u r e which i s c h a r a c t e r i s t i c of the a d s o r b a t e and the t e m p e r a t u r e , but not the a d s o r b e n t , the mechanism o f d e s o r p t i o n changes from one c o n t r o l l e d by the K e l v i n e q u a t i o n t o one c o n t r o l l e d by a s u r f a c e m i g r a t i o n i n t o and out o f the m i c r o p o r e . " • In a n o t h e r paper ( 1 5 3 ) H a r r i s  states:  "A c e r t a i n amount of e v i d e n c e i s b e i n g accumulated (149,153,154) which i n d i c a t e s t h a t below a c e r t a i n pore s i z e , b u l k l i q u i d p r o p e r t i e s cease t o a p p l y t o the adsorbed phase, and t h a t t h i s l i m i t depends both on the adsorbate and t e m p e r a t u r e , but not on the adsorbent p r o v i d e d o n l y t h a t 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 ( 1 5 5 ) a l s o s t a t e s t h a t the l i m i t i n g pore r a d i u s i s 18 ft f o r n i t r o g e n and 14 ft f o r a r g o n , both at 77 °K.  This  i s c l o s e t o the upper s i z e l i m i t f o r a micropore as d e f i n e d by D u b i n i n .  I n the same paper H a r r i s remarks:  -91-  i  15  I  20  I  25  I  30  I  35  IAO  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 a c c e p t e d t h a t t h e concept o f s u r f a c e t e n s i o n has t o be m o d i f i e d i n a m i c r o p o r e , t o t a l pore volume c o n t i n u e s to. be c a l c u l a t e d f o r microporous s o l i d s from the i s o t h e r m 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 u s i n g the b u l k v a l u e o f the l i q u i d d e n s i t y . " H a r r i s then g i v e s some d a t a ( f i g u r e 19 )using a r g o n , n i t r o g e n , oxygen and carbon monoxide as a d s o r b a t e s over a range of tern-, p e r a t u r e s on a sample of porous t i t a n i a w i t h a G u r v i t c h mean pore " r a d i u s " of about 11 &.  These a d s o r b a t e s have s i m i l a r  m o l e c u l a r 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 penet r a t i o n would not be e x p e c t e d .  He e x p l a i n s the  anomalous,  s l o p e of the apparent pore volume as determined by oxygen  as  p r o b a b l y a r i s i n g from the a b i l i t y of oxygen t o p e n e t r a t e 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 w i t h . the o t h e r gases used.  Prom t h i s d a t a he c o n c l u d e s :  "Thus i t appears t h a t a micropore can be d e f i n e d as one i n which the adsorbed phase no l o n g e r shows any o f the p r o p e r t i e s of the b u l k l i q u i d , so t h a t the t o t a l pore volume determined by the u s u a l method i s not more r e l i a b l e or m e a n i n g f u l than s u r f a c e a r e a or pore r a d i u s d e t e r m i n a t i o n s when a p p l i e d t o 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 A d s o r p t i o n Isotherms The " t " p l o t method f o r a n a l y s i s of a d s o r p t i o n i s o therms proposed by L i p p e n s and de Boer ( 1 5 6 ) has i n r e c e n t years a t t r a c t e d a good d e a l of a t t e n t i o n as a s i m p l e 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 a d s o r p t i o n i s o t h e r m s 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 a d s o r b e n t s ( 1 5 7 ) .  The  method c o n s i s t s o f p l o t t i n g the volume of n i 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 a g a i n s t the c o r r e s p o n d i n g t h i c k n e s s , t , o f the adsorbed l a y e r of n i t r o g e n on a  nonporous  FIGURE 19. (FROM APPARENT TITANIA  REFERENCE 155.)  VOLUME AS  OF MICROPOROUS  FUNCTION  OF  _  .  TEMPERATURE  0.!5r I  ADSORBATES.  •  •  0I4L  O.I3h  I  60  —1  70 TEMPERATURE,  L.  I  80 #  K  90  -94-  reference  solid. E a r l i e r work (157) had d e m o n s t r a t e d - t h a t n i t r o g e n  i s o t h e r m s on v a r i o u s nonporous s o l i d s may when p l o t t e d i n a reduced form ( i . e . v / v  be  superimposed  v e r s e s p/p  D e v i a t i o n s from t h i s s t a n d a r d i s o t h e r m may  ).  be a n a l y s e d i n  terms of m i c r o p o r e f i l l i n g and c a p i l l a r y c o n d e n s a t i o n .  The  s l o p e o f a l i n e a r " t " - p l o t p r o v i d e s a measure of the s u r f a c e a r e a and the onset of c a p i l l a r y c o n d e n s a t i o n i s r e v e a l e d by the d e p a r t u r e o f the " t " - p l o t from L i p p e n s and de Boer  linearity.  (156)  d i s c u s s e d the  inter-  p r e t a t i o n s of t h e " t " - p l o t d e v i a t i o n s at h i g h e r r e l a t i v e p r e s s u r e s and i n t e r p r e t e d some cases shown i n f i g u r e a) Curve I :  The  20.  s u r f a c e i s f r e e l y a c c e s s i b l e up t o h i g h  r e l a t i v e pressures;  the m u l t i l a y e r can form un-  h i n d e r e d on a l l p a r t s o f the s u r f a c e ;  the a d s o r p t i o n  branch o f the i s o t h e r m has the shape o f the s t a n d a r d 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 p r e s s u r e c a p i l l a r y  condensation  w i l l o c c u r i n pores of c e r t a i n shapes and  dimensions;  the m a t e r i a l t a k e s up more a d s o r b a t e t h a n  corresponds  to  the volume o f the m u l t i l a y e r .  of  t h i s curve was  The d o t t e d s e c t i o n  i m p l i e d by L i p p e n s and de Boer, t o mean  t h a t a f t e r c a p i l l a r i e s are f i l l e d ,  the s l o p e of the  " t " - p l o t decreased as the s u r f a c e o f 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 o f n i t r o g e n i s o t h e r m s on v a r i o u s porous  solids  ( A l ^ O , , T i 0 , BaSCv, ZrO„, MgO, 9  Nickel  Si0  antigorite, that as  they  i t does  pores low  have  2  and carbon  assumed  i n larger  coverage  pores.  has been c a l c u l a t e d  relative  not r e a l i s t i c  of  figure  20 a s  I t would  t o occur  Sing  (159)  appear  within  Thus t h e s u r f a c e  from t h e slope  pressures.  is  blacks).  micropores area  i n micro-  of the "t"-plot at  concluded  and e x p l a i n e d h i s reasons  this  using  approach  curve I I I  follows:  In cases 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 u p 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 (of l a r g e r pores) and i ft 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 value of the surface area. Because o f t h e nature of t h e c a l c u l a t i o n , good agreement between S and SgErp i s o n l y t o b e e x p e c t e d a n d d o e s n o t i n i t s e l f confirm the v a l i d i t y of e i t h e r value o f surface area.; I f t h e " t " - p l o t i s made u p o f t w o l i n e a r p a r t s , AB a n d CD, i t w o u l d s e e m m o r e 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, a s 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 pores except m i c r o - , pores. 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 process and t h e upt 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 volume. Assuming l i q u i d packing o f the adsorbed nitrogen molecules, J C R O P O R E °- 56 V , This T  v  0 0 1  =  M  q  s i m p l e method o f a n a l y s i s appears 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 h a s t o be assumed t o a s s e s s m i c r o pore 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 complication of capillary condensation." However, d e v i a t i o n s from pressures  (low " t " values)  linearity  i n the direction  sorption  c o u l d be due t o m i c r o p o r e  sorption  due t o t h e e n h a n c e d  bination  of chemisorption  bination  of these  filling,  potential  field  at low r e l a t i v e of increased adincreased ad(105) o r a c o m -  a n d p h y s i c a l a d s o r p t i o n o r a n y com-  possibilities.  -97-  V - APPARATUS, MATERIALS AND  EXPERIMENTAL PROCEDURES  A- I n t r o d u c t i o n Two  t y p e s of gas a d s o r p t i o n apparatus  s t r u c t e d f o r t h i s work; mining  a continuous  were con-  flow device f o r deter-  s m a l l s u r f a c e areas such as those of paper s h e e t s  and  a v o l u m e t r i c d e v i c e f o r d e t e r m i n i n g complete i s o t h e r m s . supplementary p i e c e of equipment was  A  b u i l t f o r the s o l v e n t  exchange d r y i n g o f p u l p 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  a s i n g l e sample o f never d r i e d , f u l l y b l e a c h e d ,  came from  commercial  grade k r a f t p u l p o b t a i n e d from the M a c M i l l a n - B l o e d e l Co. L t d . , Harmac d i v i s i o n at Nanaimo, B. C. c o a s t a l Douglas f i r and western aldehyde was  The  p u l p was  hemlock.  a blend of  A few drops o f  were added t o stop b i o l o g i c a l d e g r a d a t i o n .  kept under r e f r i g e r a t i o n at a l l t i m e s .  The  formsample  S p e c i f i c a t i o n s o f the  gases and c h e m i c a l s used are l i s t e d i n appendix E. C. Continuous The was  developed  f l o w A d s o r p t i o n Apparatus continuous  f l o w method of d e t e r m i n i n g s u r f a c e a r e a  by N e l s e n and E g g e r t s e n  Stone and N i c k e r s o n  (160) and adapted by  ( l 6 l ) f o r use on paper s h e e t s .  The  equip-  ment c o n s t r u c t e d f o r t h i s work i s b a s i c a l l y the same as t h a t developed  by Stone and N i c k e r s o n 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 The  continuous  22. f l o w method i s based on the changes of  t h e t h e r m a l c o n d u c t i v i t y o f the gas m i x t u r e w i t h  composition.  A known m i x t u r e o f n i t r o g e n and h e l i u m i s passed  through  sample w i t h the e f f l u e n t b e i n g m o n i t o r e d  by a t h e r m a l  the  -98-  FIGURE. 21. BASIC  UNITS C f  THERMAL CONDUCTIVITY  MILUVOLT RECORDER  A "ADSORPTION PEAK D ~ DESORPTION  PEAK  C -CALIBRATION  PEAK  CONTINUOUS  FLOW  EQUIPMENT  PURE NITROGEN  OF LIQUID NITROGEN  NITROGEN THERMOMETER PROBES  cr  bl  tj Z  12 V POWER SOURCE  o  BACK PRE-SSURE MANOMETER He-N  2  Z <  SAMPLE TUBES"  UJ  ct  MIXTURE FEED DEWAR FLASK  EXHAUST THERMAL ^CONDUCTIVITY CELL  3 </>  CO  8 ae  TO MILLIVOLT RECORDER  LIQUID  N  3 O a.  2  2 NITROGEN THERMOMETER  OIL FILLED SRINGE CAPS FOR CALIBRATION  M  PURIFIED NITROGEN  FIGURE 22: SCHEMATIC  DIAGRAM  OF CONTINUOUS  FLOW  EQUIPMENT  EXHAUST  -100-  conductIvi.ty. c e l l coupled t o 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 t h e 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 c o n s t a n t b a s e l i n e on t h e r e c o r d e r chart,, t h e 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 nitrogen  by the paper i s i n d i c a t e d by a peak on t h e r e c o r d e r c h a r t i n d i c a t i n g t h e change i n c o m p o s i t i o n o f t h e gas m i x t u r e .  As  e q u i l i b r i u m i s a g a i n e s t a b l i s h e d , t h e c h a r t pen w i l l r e t u r n to t h e 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 t h e sample t o warm up t h e r e b y d e s o r b i n g t h e adsorbed  nitrogen.  T h i s desorbed  n i t r o g e n i s d e t e c t e d by  the t h e r m a l 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 t h e o p p o s i t e s i d e o f t h e base l i n e t o appear.  The volume o f  n i t r o g e n r e p r e s e n t e d by these two peaks s h o u l d be t h e same and t h e volumes r e p r e s e n t e d a r e determined of the d e t e c t o r .  by c a l i b r a t i o n  T h i s c a l i b r a t i o n i s o b t a i n e d by i n j e c t i n g  known q u a n t i t i e s o f pure n i t r o g e n o r h e l i u m i n t o t h e stream and m o n i t o r i n g t h e r e s u l t i n g peak s i z e s .  As t h e c o m p o s i t i o n  of t h e h e l i u m - n i t r o g e n gas m i x t u r e i s known, and t h e s a t u r a t i o n p r e s s u r e o f t h e l i q u i d n i t r o g e n can be determined  from t h e .  n i t r o g e n vapour p r e s s u r e thermometer, t h e p a r t i a l p r e s s u r e o f n i t r o g e n can be determined.  ;  The p a c k i n g o f t h e sample i n t o t h e sample tube i s .very important i f good r e s u l t s a r e t o be o b t a i n e d .  Large  dead  spaces must be a v o i d e d and a l l s u r f a c e s s h o u l d be a c c e s s i b l e to  t h e f l o w i n g gas i n o r d e r t o a v o i d l o n g d e l a y s w h i l e t h e  n i t r o g e n d i f f u s e s t o o r from t h e sample s u r f a c e .  Handsheets,  were c u t 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 t h e sample tube d e s c r i b e d i n f i g u r e 23a.  !  GLASS SPACER 7 mm TUBING 6 mm CAPILLARY TUBING  OUT THINLY. FIG.23a  SAMPLE PAPER  SAMPLE  TUBE  FOR  FIG. 23b  SAMPLES. TUBES  FOR  SAMPLE POWDER  CONTINUOUS  FLOW  ADSORPTION  TUBE  FOR  SAMPLES. EQUIPMENT.  -102-  The equipment has been used by o t h e r workers (162) f o r s u r f a c e a r e a measurements o f m a t e r i a l s such as g a l e n a and marmatite powders of 65/1.00 mesh s i z e .  In t h i s  c a s e , a sample tube o f the shape g i v e n i n f i g u r e 23-b used.  was  These m i n e r a l samples r e p r e s e n t e d a unique problem  i n t h a t the a d s o r p t i o n took a minimum of t e n minutes t o complete because o f 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 t e m p e r a t u r e s .  Thus, as Nelson; and  E g g e r t s o n found (160), o n l y d e s o r p t i o n peaks c o u l d be used on such samples.  T h i s problem was not encountered'when  using  paper samples and thus b o t h a d s o r p t i o n and d e s o r p t i o n peaks c o u l d be used. The samples o f paper were d r i e d by p a s s i n g a stream of the He-N  2  m i x t u r e at about 20 mis p e r minute t h r o u g h 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 b a t h at 105 °C f o r 30 m i n u t e s .  Provision  was  a l s o made f o r the v e n t i n g o f the m o i s t u r e c o n t a i n i n g exhaust gas i m m e d i a t e l y a f t e r the sample t u b e . Once the samples' were d r i e d , the system was and the f l o w of the He-N as measured  2  closed  m i x t u r e a d j u s t e d t o 15 mis per min.  by the soap bubble f l o w 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 c o n s t a n t zero t r a c e on the .rec o r d i n g m i l l i v o l t m e t e r m o n i t o r i n g the t h e r m a l c o n d u c t i v i t y c e l l , the sample was s l o w l y immersed bath.  i n the l i q u i d n i t r o g e n ,  A slow immersion (up t o 5 m i n u t e s ) was r e q u i r e d t o  a v o i d d i s t u r b i n g the f l o w e q u i l i b r i u m .  :  The vapour p r e s s u r e .  of the l i q u i d n i t r o g e n b a t h and the t h e r m a l c o n d u c t i v i t y  cell  output were r e c o r d e d as the s y s t e m ' r e t u r n e d t o e q u i l i b r i u m .  -103-  A f t e r t h e 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 , t h e l i q u i d  nitrogen  b a t h was removed from t h e sample.  pressure  and t h e r m a l  A g a i n t h e vapour  c o n d u c t i v i t y c e l l output were r e c o r d e d .  p r o c e e d u r e was r e p e a t e d  This  s e v e r a l times u s u a l l y i n t e r s p a c e d w i t h  c a l i b r a t i o n samples which were i n j e c t e d u s i n g a gas s y r i n g e . These c a l i b r a t i o n samples were s i z e d t o b r a c k e t t h e volume o f the e x p e r i m e n t a l and  adsorption.  25.38 p e r c e n t  Three N ~He r a t i o s (5.06, 15.60 2  n i t r o g e n i n h e l i u m ) were u s e d , t h e system  b e i n g 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 V o l u m e t r i c The  Apparatus  v o l u m e t r i c a d s o r p t i o n equipment c o n s t r u c t e d f o r  t h i s work i s s i m i l a r t o t h e s t a n d a r d v o l u m e t r i c equipment d e s c r i b e d by Gregg and S i n g (20) w i t h emphasis on r e d u c i n g the dead volume as much as p o s s i b l e . schematic drawing of t h i s apparatus,  Figure 2 4 i s a t h e equipment i s con-  s t r u c t e d o f 1 mm i n s i d e d i a m e t e r c a p i l l a r y t u b i n g w i t h m a t c h i n g 5.5 mm c a l i b r a t e d tubes f o r t h e p r e s s u r e manometer. A l l measurements a r e t a k e n u s i n g a c a t h e t o m e t e r c a p a b l e  o f measure-  ment t o 0.001 cm. When u s i n g t h e equipment w i t h s o l v e n t exchange d r i e d p u l p s t h e sample was connected w h i l e s t i l l pentane.  immersed i n n-  The sample tube was t h e n Immersed i n a water bath  at 20 ° C and t h e n-pentane p u l l e d o f f by vacuum pumping a t a r a t e which r e q u i r e d 3 t o 4 h r s . f o r t h e s o l v e n t t o d i s a p p e a r . The  sample was t h e n e v a c u a t e d f o r a t l e a s t 12 hours under a  vacuum o f about 5 m i c r o n s p r e s s u r e . exchanged, 12 hours e v a c u a t i o n  F o r samples n o t s o l v e n t  at 5 microns pressure  removed  VACUUM PUMP  McLEOD GAUGE  GAS CYLINDER  K  GAS STORAGE  CAU8RA1  0  FIGURE 24.  'VOLUME  BULBS VAPOUR PRESSURE PRESSURE MANOMETER MANOMETER VAPOUR PRESSURE PROBE SAMPLE TUBE  VOLUMETRIC  ADSORPTION APPARATUS  0  -105-  any v o l a t i l e s present..  The sample was i s o l a t e d under t h e  vacuum and t h e b a l a n c e o f t h e system f l u s h e d w i t h t h e gas t o be used.  F o r t h e l a s t f l u s h i n g t h e sample tube was r e -  opened t o t h e system.  The t e s t s e c t i o n was pumped down'  to t h e d e s i r e d p r e s s u r e , t h e p r e s s u r e measured, and t h e 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 r e a d i n g s a t l e a s t two minutes a p a r t 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 o f gas were i n t r o d u c e d t o t h e sample by s l o w l y f i l l i n g t h e gas r e s e r v o i r b u l b s w i t h mercury, o r by i s o l a t i n g t h e sample, i n c r e a s i n g t h e p r e s s u r e o f t h e r e s t of t h e t e s t s e c t i o n and s l o w l y b l e e d i n g t h i s i n c r e a s e d p r e s s u r e i n t o t h e sample t u b e .  The vapour p r e s s u r e o f t h e l i q u i d  n i t r o g e n was measured each time by means o f t h e vapour p r e s s u r e thermometer.  The l e v e l o f t h e l i q u i d  was.maintained c o n s t a n t .  nitrogen  F o r p o i n t s on t h e d e s o r p t i o n  i s o t h e r m , gas was removed i n a manner analogous t o t h e method used i n a d s o r p t i o n except t h a t gas was removed r a t h e r than added.  The whole system was kept at a f a i r l y c o n s t a n t  temperature which was measured t o 0.1 °F and t h e temperature dependent  v a r i a b l e s were c o r r e c t e d t o a base temperature o f 20 °C.  The atmospheric p r e s s u r e was measured on a barometer a c c u r a t e to  0.0025 cm Hg.  Sample p a c k i n g was a c r i t i c a l parameter. t h a t f o r s o l v e n t exchanged  I t was'found  from wet s t a t e p u l p s , . t h e best r e -  s u l t s were o b t a i n e d w i t h a sample tube made out o f 7 mm g l a s s tubing. rod  The p u l p was packed c o n c e n t r i c a l l y around a 2 mm g l a s s  w h i l e t h e tube assembly was immersed i n d i s t i l l e d  water.  The p u l p f i b r e s were d i s p e r s e d i n t h e water and g e n t l y packed  - 105  down w i t h The  minimal  two-mm t u b e  change similar weight surface  drying. to of  that  pressure  i n the The used  s a m p l e was  area  i n the  to  centre  paper  a  -  leave was  sheets  clearance  removed  continuous  varied  to  tube.  after  were packed  i n the  give  flow  about  between  solvent  in a  ex-  manner  apparatus.  10-25  fibres.  sq.  m.  The of  -106-  E.  S o l v e n t E x t r a c t i o n Apparatus W h i l e the s o l v e n t exchange t e c h n i q u e  for retaining  the w a t e r s w o l l e n s t r u c t u r e o f c e l l u l o s e has been q u e s t i o n e d  in  s e c t i o n I I o f t h i s work, the d e c i s i o n t o use t h i s t e c h n i q u e  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 The 25.  The  s o l v e n t e x t r a c t i o n equipment i s shown i n f i g u r e  methanol and n-pentane were s t o r e d over magnesium  t u r n i n g s and The  thought t o e x i s t .  c l e a n , f i n e l y d i v i d e d sodium m e t a l r e s p e c t i v e l y .  m e t h a n o l was  r e f l u x e d over magnesium t u r n i n g s f o r a  minimum o f 30 minutes p r i o r t o the sample b e i n g  connected.  An e x t r a c t i v e f l o w r a t e of about 100 ml./hour was possible  used where  ( t h e h e a v i l y b e a t e n p u l p s r e s t r i c t e d f l o w too much  f o r flows of t h i s magnitude).  I n a l l c a s e s , 350-400 mis  o f m e t h a n o l were e l u t e d t h r o u g h the sample.  The  t i l l a t i o n f l a s k had magnesium t u r n i n g s t o act as  disdehydrating  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 m e t a l f o r  a minimum of 30 minutes p r i o r t o the b e g i n n i n g traction.  Care was  of the  ex-  t a k e n at a l l times t o a v o i d p o s s i b l e con-  t a m i n a t i o n of the sample w i t h m o i s t u r e  i n c l u d i n g atmospheric  moisture.  h e l d t o about 100  A g a i n the s o l v e n t f l o w was  mis./  hour w i t h a t o t a l e x t r a c t i v e f l o w of about 350-400 mis. When the s o l v e n t e x t r a c t i o n was tube was  removed from the s o l v e n t e x t r a c t i o n equipment  capped t o a v o i d p o s s i b l e c o n t a m i n a t i o n moisture.  c o m p l e t e , the sample  The  d r a i n was  and  w i t h atmospheric  sealed with a glass blowing  torch.  •107FIGUKE  25.  SOLVENT  EXTRACTION  APPARATUS  TUBE PACKED WITH FRESHLY REGENERATED SILICA GEL  ^  B A L L JOINT 2 mm TUBlWG  SAMPLE 7 lam TUBING  SAMPLE  TUBE  -108-  The sample was t h e n c o n n e c t e d t o t h e v o l u m e t r i c a p p a r a t u s . F. B e a t i n g o f P u l p The p u l p was beaten i n a P . F . I , m i l l f o r v a r i o u s l e n g t h s of t i m e w i t h a l l o t h e r c o n d i t i o n s b e i n g h e l d constant at the c o n d i t i o n s l i s t e d  below:  S i z e o f charge: 20g. ( d r y p u l p ) a t 10% s o l i d s l o a d i n g : 3-4 Kg/cm o f b a r l e n g t h The p u l p samples were b e a t e n as f o l l o w s : Time b e a t e n  No. o f 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 b e a t e n a t each l e v e l , d i l u t e d t o f i v e p e r c e n t s o l i d s c o n c e n t r a t i o n and b l e n d e d .  The r e -  s u l t i n g lOOg samples were used t h r o u g h o u t t h e e x p e r i m e n t s . G. Paper T e s t i n g Handsheets were made i n conformance S t a n d a r d C-4.  w i t h CP.P.A.  The s h e e t s 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 m a i n t a i n e d a t 72 °F and 50 p e r c e n t r e l a t i v e h u m i d i t y . Tear t e s t s and b u r s t t e s t s were p e r f o r m e d i n conformance C P . P . A . S t a n d a r d s D-9 and D-8 r e s p e c t i v e l y .  Tensile  with  tests  were p e r f o r m e d 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 C P . P . A . S t a n d a r d D-6.  Sheet t h i c k n e s s e s were  d e t e r m i n e d on a T e s t i n g M a c h i n e s , I n c . micrometer model 549 i n a c c o r d a n c e w i t h C P . P . A . S t a n d a r d D-4.  - 1 0 9 -  H. E x p e r i m e n t s Performed F r a c t i o n s of the main b u l k sample were beaten  one,  t h r e e , f i v e and t e n minutes i n the P . F . I , m i l l as d e s c r i b e d previously.  The Canadian S t a n d a r d F r e e n e s s o f each o f  t h e s e p u l p s was  determined.  Unbeaten  and b e a t e n p u l p s were s o l v e n t exchange  from a water s u s p e n s i o n .  N i t r o g e n and argon i s o t h e r m s  were d e t e r m i n e d on each o f t h e s e s o l v e n t exchange samples.  dried  dried  Oxygen i s o t h e r m s were d e t e r m i n e d on the u n b e a t e n ,  beaten one minute and beaten t h r e e minutes samples.  Some  samples were d u p l i c a t e d . Samples o f never d r i e d , unbeaten p u l p were a i r d r i e d t o v a r i o u s m o i s t u r e c o n t e n t s and t h e n s o l v e n t dried.  A handsheet  sample was a i r d r i e d and t h e n vacuum  d r i e d at 5 m i c r o n s p r e s s u r e , the sample tube f i l l e d n i t r o g e n and t h e n the sample was Throughout  exchange  s o l v e n t exchange  with  dried.  t h i s work, t h i s sample i s r e f e r r e d t o as the  vacuum d r i e d - s o l v e n t exchange  d r i e d sample.  therms were d e t e r m i n e d on a l l samples.  Nitrogen iso-  An oxygen i s o t h e r m  was d e t e r m i n e d on the vacuum d r i e d - s o l v e n t exchange sample.  dried  Argon i s o t h e r m s were d e t e r m i n e d on the vacuum  d r i e d - s o l v e n t exchange  d r i e d sample and the 5-3 p e r c e n t  m o i s t u r e c o n t e n t sample. Isotherms of n i t r o g e n , argon and oxygen were d e t e r mined on vacuum d r i e d , unbeaten handsheets which were not s o l v e n t exchange  dried.  The c o n t i n u o u s f l o w a d s o r p t i o n a p p a r a t u s was  used  to d e t e r m i n e the B.E.T. s u r f a c e a r e a o f handsheets o f a l l the  -110-  p u l p s used. Handsheets were made from t h e s e p u l p s f o r p h y s i c a l testing.  T e n s i l e , s t r e t c h , sheet d e n s i t y , b u r s t and t e a r  were determined on each s e t o f handsheets.  -111V I - EXPERIMENTAL RESULTS AND A.  I s o t h e r m s , o f N i t r o g e n , A r g o n and N i t r o g e n and  of  mental  Any  shown i n f i g u r e s of the  d i f f e r e n c e s c o u l d be  f i b r e s may  n o t be  t o p a c k i n g and as c o m p l e t e l y  26-28.  experi-  due  to  w i t h s o l v e n t e x c h a n g e d r y i n g as t h i s  apparently quite sensitive  accessible  are  on d u p l i c a t e s a m p l e s  show t h e r e p r o d u c i b i l i t y  techniques.  difficulties  Oxygen  isotherms  s o l v e n t exchange d r i e d p u l p s  These i s o t h e r m s  is  argon  DISCUSSION  thus  technique the  less  s o l v e n t exchange  dried. Appendix I i s a study volumetric  apparatus  calculated  values determined  data c a l c u l a t e d appendices studied  from  I and  and  the e f f e c t  these  d u p l i c a t e samples.  K show t h e e f f e c t s  f o r n i t r o g e n and  28.  s e q u e n t i a l isotherms  w i t h the  second  isotherm.  to  the  d a t a .given I n  not  due  to  parameters  error.  argon  is  shown i n f i g u r e s  were d e t e r m i n e d  and  first  show t h a t t h e  depressure  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- •  isotherm i s started.  the r e s u l t i n g  26  continuously,  i s v e r y d e p e n d e n t on t h e r e l a t i v e  w e r e commenced f r o m  be  compares  of the papermaking  These s e q u e n t i a l i s o t h e r m s Isotherm  sorption  The  isotherm being a c o n t i n u a t i o n of the  sorption which  Appendix K  the  s u p e r i m p o s a b i l i t y of s e q u e n t i a l a d s o r p t i o n  isotherms The  e r r o r s h a v e on  i n t h i s work.  i n t h i s w o r k a r e m e a s u r a b l e and The  as c a n  of the p o s s i b l e e r r o r s i n the  lower  The  relative  desorption isotherms  seen from  figures  26  and  second  desorption  isotherms  pressures than the f i r s t are 28.  significantly The  argon  and  different  desorption  - I l l  isotherm  i s more  effect.  Thus a h i g h  beginning parable  sensitive  desorption Isotherms  were d e t e r m i n e d are  wood  pulp  listed  t h e n i t r o g e n one t o  pressure  isotherm  i s required prior  i n order  o f n i t r o g e n , argon  on s o l v e n t exchange 29  t o 37.  isotherms  handsheets.  i n Appendix  this  t o assure  to  com-  isotherms.  shown i n f i g u r e s  argon and oxygen  than  relative  the desorption  a -  A.  a n d o x y g e n a t 78  dried  Figure  38  wood  f o r these  and  shows t h e n i t r o g e n ,  onto, v a c u u m d r i e d  The d a t a  pulps  °K  unbeaten  isotherms  are  -112-  FIGURE 26 280 NITROGEN ISOTHERMS ON DUPLICATE SOLVENT EXCHANGE DRIED UNBEATEN PULP SAMPLES o FIRST ISOTHERM • SECOND ISOTHERM A SAMPLE 2.  - 1 1 3 -  260  FIGURE 27. NITROGEN  240 I-  SOLVENT EXCHANGE BEATEN  200  <»  g 120  Q UJ CO CC  o g 80 3  o 40  FOR  o SAMPLE A  IT 560  ISOTHERMS  SAMPLE  SOLID  ON  DRIED  10 MIN.  IN  DUPLICATE PULP RF.I. MILL  I. 2.  POINTS = DESORPTION  -114-  280-  FIGURE 28. ARGON  ISOTHERMS  EXCHANGE  DRIED  ON DUPLICATE SOLVENT UNBEATEN PULP SAMPLES  240  200  N a:  co  O  FIRST  CYCLE  •  SECOND CYCLE  A  SECOND  ISOTHERM ONE  ISOTHERM  160  E a  120  UJ CD OC O CO  o < LU 2  3 o >  80  SOLID SYMBOLS = DESORPTION  40  0*0  0.2  0.4  0.6  P/Po  0.8  1.0  - 1 1 5 -  -116-  -117-  -118-  280r FIGURE 32. ISOTHERMS 240  a:  200  CO  160 a ui m  g 120  co  Q < Ul  o  >  OF NITROGEN  AND ARGON  AT 78° K ON SOLVENT EXCHANGE DRIED PULP  BEATEN 5 MIN.  o  NITROGEN  A  ARGON  SOLID SYMBOLS ARE DESORPTION  -119-  FIGURE 33. ISOTHERMS OF NITROGEN 8 ARGON 280  AT 78°K ON SOLVENT EXCHANGE DRIED PULP BEATEN 10 MIN.  240  200  \  160  a? Hf  co i2 120 E Q LU 00  CC  o 80 CO  a <  LU -I  O >  O  NITROGEN  A  ARGON  SOLID SYMBOLS ARE  DESORPTION  y  -121-  6D  r  0.0  0.2  0.4  0.6  0*8  1.0  -122-  -124-  l.4|  l.2h  FIGURE 38. ADSORPTION ISOTHERMS OF NITROGEN, ARGON AND OXYGEN ON VACUUM DRIED UNBEATEN PULP SHEETS  1.0  o NITROGEN  0L  </5 0.81  A ARGON • OXYGEN  Q Id CO  0.6  SOLID SYMBOLS • DESORPTION  DC  o o  * 0.4| 2 O  > 0.2  ****** * o % A  0.0» 0.0  0.2  0.4  P/ P«  0.6  0.8  -125de Boer (page 172  o f r e f e r e n c e 20)  has  classified  h y s t e r e s i s l o o p s and r e l a t e d these c l a s s i f i c a t i o n s t o d e f i n i t e pore shapes.  However, i n o r d e r t o do t h i s  success-  f u l l y , an a d s o r b e n t w i t h a v e r y narrow pore d i s t r i b u t i o n i s required.  O t h e r w i s e , 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 o f the o v 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  t h a t p r e d i c t e d by the pore geometry.  from  The shapes of the  h y s t e r e s i s l o o p s o b t a i n e d i n t h i s work a r e not a c c e p t a b l e for  t h i s type o f i n t e r p r e t a t i o n as t h e r e a p p a r e n t l y are  wide pore s i z e d i s t r i b u t i o n ' s .  The shape o f the h y s t e r e s i s  l o o p s found by a d s o r p t i o n of n i t r o g e n , argon and oxygen  on  c e l l u l o s e c o u l d f i t any o f 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 s i d e d f i s s u r e  models.  The shapes o f t h e n i t r o g e n , argon and oxygen ads o r p t i o n isotherms  i n d i c a t e t h a t the argon i s o t h e r m  cepts the s a t u r a t i o n pressure s o r p t i o n v a l u e whereas  (p/p = 1.0)  inter-  with a f i n i t e  the n i t r o g e n and argon  ad-  isotherms  a p p a r e n t l y approach the s a t u r a t i o n p r e s s u r e 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 o f the n i t r o g e n and i s o t h e r m s on s o l v e n t exchange  oxygen  d r i e d water s w o l l e n p u l p s  the shape o f the n i t r o g e n and oxygen i s o t h e r m s  and  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.  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 have been i n t e r p r e t e d t o mean t h a t m o n t m o r i l l o n i t e c o n t a i n s laminae which open up as ad-  -126-  FIGURE 39 ISOTHERMS  (FROM REFERENCE 163) ON MONTMORILLONITE  -127-  s o r p t l o n proceeds f o r m i n g p a r a l l e l s i d e d pores (150, 163). There i s no l i m i t t o a d s o r p t i o n .  On d e s o r p t i o n , a meniscus  i s p r e s e n t which causes h y s t e r e s i s .  I t i s therefore  suggested  t h a t p o s s i b l y the s o l v e n t exchange d r i e d p u l p s , which may a l 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 t o m o n t m o r i l l o n i t e a t h i g h e r 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 t o occur more r e a d i l y w i t h a d i a t o m i c molecule  than a monatomic molecule  because o f the;  p o s s i b i l i t y o f induced p o l a r i z a t i o n and thus more e n e r g e t i c adsorption of higher layers.  A l s o c o n t r i b u t i n g t o t h e more  e n e r g e t i c a d s o r p t i o n o f h i g h e r l a y e r s a r e t h e heats o f vapouri z a t i o n which i n d i c a t e a more e n e r g e t i c a d s o r p t i o n f o r t h e diatomic molecules.  The heats o f v a p o u r i z a t i o n (164) f o r  n i t r o g e n and oxygen a r e 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 v a l u e i s o n l y 72.6 B . t . u . / l b . * Other p o s s i b l e e x p l a n a t i o n s f o r t h i s d i f f e r e n c e i n the shape o f i s o t h e r m s  o f the d i a t o m i c a d s o r b a t e s ,  and oxygen and the monatomic a d s o r b a t e , a)  nitrogen  argon, are:  The o u t e r adsorbed l a y e r s o f a r g o n , which i s assumed t o behave as a s u p e r - c o o l e d  l i q u i d when adsorbed onto  a s u r f a c e , may r e v e r t t o t h e s o l i d s t a t e which would be expected  under t h e c o n d i t i o n s o f t h e experiment.  Thus the e f f e c t s o f s u r f a c e t e n s i o n are l o s t and t h e model o f a K e l v i n e q u a t i o n c o n t r o l l e d c o n d e n s a t i o n i s no l o n g e r a p p l i c a b l e , r e s u l t i n g i n no b u l k condens a t i o n i n pores u n t i l s a t u r a t i o n p r e s s u r e i s reached. *  Extrapolated bulk l i q u i d  value  -128b)  The " s t a n d a r d " losic of  adsorbed  approaches argon  sorbed  unity.  This  cellu-  at higher  measured  relative  Is doubtful  crystals  increase i n layers  of zinc o f argon  ad-  pressures.  vapour pressure  by t h e argon  saturation  pressure  possibility  a d s o r p t i o n on s i n g l e  The s a t u r a t i o n  thus  on a non p o r o u s  as t h e r e l a t i v e  . (165) shows a r a p i d  c)  isotherm  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  layers  as  argon  probe,  o f argon  solid,  as  i s not the true  vapour  pressure  of the supercooled  the relative  pressure  i s i n error,  liquid,  possibly .  b e i n g t o o l o w (166).  B.  B.E.T.  Analysis of  Isotherms  B.E.T. a n a l y s e s B.E.T. p l o t s solvent  w e r e made o n e a c h  f o rn i t r o g e n , argon  exchange  dried,  unbeaten  These  plots  lists  t h e B.E.T. m o n o l a y e r  various assumed  are typical  samples ^  pulp  used.  volumes  The v a l u e  noted.  The v a l u e s  of A  ft  of A  from  and  g./ml.  I.1967  equation f o r  Extrapolated  4 using  argon  from  m  Table  40. 15  of the  &  this  i n table  work  unless  15 a r e  &  densities  and oxygen  liquid  of the  f o rnitrogen i s  throughout given  m calculated  obtained.  and s u r f a c e areas  2 16.2  isotherms  a r e shown i n f i g u r e  of the results  t o be t h e s t a n d a r d  otherwise  and oxygen  of the isotherms.  (160) o f 1.452*  respectively.  densities.  -129-  Table 15:  B. E. T. Monolayer Volumes and. Areas o f S o l v e n t Exchange D r i e d Samples B. E. T. Monolayer Volume, v , (mis.(S.T.P.)/g.) Sample  Minutes Beaten  B. E. T. A r e a , A Moisture Content*  N i t r o g& e n (A =16.2) m  v  m  A  0  Saturated  44.28  193.0  0  Saturated  44.37  193-4  1  Saturated  41.75  182.0  3  Saturated  38.65  168.5  5  Saturated  36.22  157.8  10  Saturated  36.99  161.3  . 0  Vacuum dried  Argon (A =13.9) A v m 170.1 45.38 177.4 47.32 163.5 43.61 153.5 40.95 143.2 38.2 143.2 38.2  Oxygen  1. 501  m  1.187  5.17  1.307  4.90  1. 921  7.20  0  5-3  1.677  7.31  0  14.4  5.109  22.27  0  33.6  *  (sq.m./g.)  28.15  122.7  Wt. m o i s t u r e x 100 / (wt. m o i s t u r e + s o l i d s )  v  (A =12.5) m  A  m 50.43  170.0  48.85  164.5  45. 54  153.5 UJ  o I  5.06  -130-^  Table 15 shows, t h e agreement between t h e B.E.T surface, areas d e t e r m i n e d by argon and oxygen a d s o r p t i o n . i s q u i t e good, however, t h e agreement between these v a l u e s and those determined from t h e 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 i s not as good, t h e n i t r o g e n v a l u e s b e i n g about 10 p e r c e n t  higher.  The r a t i o s o f these s u r f a c e areas a r e l i s t e d i n t a b l e 16. Table 16: R a t i o s Showing Dependence of B.E .T. Surf, on Adsorbate Sample Minutes beaten  R a t i o o f .Areas Moisture Content  Ar  °2  °2  Nj  N  0.88  1.00  2  Ar  0  Saturated  0.88  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  Vacuum d r i e d  0.95  0.98  1.03  0 0  5-3  0.985  Some o f t h e d e f i c i e n c i e s o f t h e B.E.T. have been d i s c u s s e d i n s e c t i o n IV-A.  technique  These r e s u l t s de-  monstrate t h e problem o f 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 a r e a , Am , o f an adsorbed m o l e c u l e .  The c l o s e agreement °  between B.E.T. areas as determined from argon and oxygen i s o t h e r m s may be f o r t u i t o u s o r may be due t o t h e s i m i l a r b u l k p h y s i c a l p r o p e r t i e s (vapour p r e s s u r e , c r i t i c a l p r o p e r t i e s , m o l a l volume) o f t h e two a d s o r b a t e s .  The b u l k p h y s i c a l  -131-  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 s o l v e n t exchange to  d r i e d from low water c o n t e n t s may  samples  be  due  the f a c t t h a t 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 s m a l l e r pores i n t h e s e 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. s u r f a c e  areas a p p a r e n t l y improves as the pore volume d i s t r i b u t i o n s h i f t s t o the s m a l l e r pore s i z e s . q u a n t i t y of data permits only  However, the s m a l l  tentative  ' . conclusions.  I f one f o r c e s the argon and oxygen d a t a t o agree w i t h .the n i t r o g e n d a t a f o r solvent, exchange  dried  swollen  p u l p s , the v a l u e s o f the adsorbed m o l e c u l a r c r o s s - s e c t i o n a l 2  a r e a s , A , must be changed 2  from 1 3 - 9 A  '  2  and 1 2 . 5 ft t o  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 a r e a f o r a r g o n , 15.4 ft , i s the v a l u e recommended by Emmett and C i n e s ( 1 6 6 ) 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 .  f o r argon  However, con-  s i d e r i n g the c o n c l u s i o n s o f A r i s t o v and K i s e l e v ( 1 0 5 )  and t h e  apparent agreement between the B.E.T. s u r f a c e a r e a s from argon and oxygen i s o t h e r m s , i t might be more l o g i c a l t o change t h e c r o s s - s e c t i o n a l a r e a of n i t r o g e n from 1 6 . 2  t o 1 4 . 6 ft t o  a c h i e v e agreement because argon would seem t o be a more i d e a l a d s o r b e n t , as i t i s monatomic and n o n - r e a c t i v e .  The  proposed  2  c r o s s - s e c t i o n a l a r e a of 1 4 . 6 ft i s g r e a t e r t h a n the v a l u e of 2  1 4 . 2 ft recommended by Kodera and O n i s i ( 1 0 7 )  2  and i s between the v a l u e s o f 1 3 - 6 A r i s t o v and K i s e l e v ( 1 0 5 ) dehydroxylated s i l i c a s  f o r g e n e r a l use  and 14.8 ft s u g g e s t e d by  f o r hydroxylated s i l i c a s  respectively.  and  -132-  B.E.T. s u r f a c e areas f o r vacuum d r i e d sheets were d e t e r m i n e d t o be 0.510, 0..508. and 0.433 s q . m./g. f o r  argon and oxygen i s o t h e r m s  respectively.  These  nitrogen,  isotherms  were n o t c o n s i d e r e d r e l i a b l e as t h e s u r f a c e a r e a o f t h e samples was  thought t o be t o o s m a l l f o r r e l i a b l e r e s u l t s on t h e  volumetric device.  However, t h e agreement between t h e  n i t r o g e n i s o t h e r m B.E.T. s u r f a c e a r e a and t h e B.E.T. s u r f a c e a r e a d e t e r m i n e d on t h e c o n t i n u o u s  flow device  (which i s de-  s i g n e d f o r a r e a s o f 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 o f b e a t i n g on t h e s u r f a c e a r e a o f wood  p u l p as measured by s o 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 s shown i n t a b l e 15 and f i g u r e 4 l .  A l s o shown i n  f i g u r e 4 l i s s i m i l a r d a t a o f Stone and S c a l l a n (16).  The  s u r f a c e a r e a decrease w i t h b e a t i n g found i n t h i s work i s c o n t r a r y t o t h e t r e n d found by Stone and S c a l l a n (16) and by Thode e t a l (54) (see t a b l e 6).  However, G r o t j a h n and Hess  (49) u s i n g argon as t h e a d s o r b a t e found no s i g n i f i c a n t i n surface area  (see t a b l e 4).  No s a t i s f a c t o r y  change  explanation  has been found f o r t h i s d i f f e r e n c e o t h e r t h a n t h e p u l p s  used  were q u i t e d i f f e r e n t u n l e s s one assumes t h e s o l v e n t 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 s u r f a c e a r e a l o s s .  The  p u l p s used i n t h e v a r i o u s 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 p u l p 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 w h i l e Stone and S c a l l a n used a b l e a c h e d  s p r u c e s u l p h i t e p u l p and  Thode e t a l used a commercial western hemlock s u l p h i t e pulp.  G r o t j a h n and Hess d i d not s p e c i f y t h e type o f p u l p  -133-  i i  i  •  10  1  1  1000  DRIED AT 105 ° C  •  DRIED AT 105°C FOLLOWED BY HEAT TREATMENT AT 150* C  •  THIS WORK, NEVER DRIED  '  1  2000  3000  REV  FIGURE 41: THE EFFECT OF DRIED  B.E.T.  i  4000  i  5000  i —  6000  [P.F.I. MILL]  BEATING ON THE SOLVENT  SURFACE  AREA  EXCHANGE  -134u s e d 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 t h e name, M'odocord.  Stone and S c a l l a n  differences  i n the behavior of k r a f t  s o l v e n t exchange  dried  p u l p s were d i f f e r e n t ;  (60) h a v e r e p o r t e d  samples.  and s u l p h i t e p u l p s w i t h  The m a c h i n e s  used t o beat t h e  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 u s e d a b a l l m i l l H e s s u s e d a S t r e c k e r - M u h l e M o d e l DKM 00 The  significant  ranges o f t h e measured  and G r o t j a h n and  machine.  surface areas of beaten  n e v e r d r i e d p u l p s a s d e t e r m i n e d by t h e v a r i o u s w o r k e r s a r e summarized  In table  17.  '  T a b l e 17:  R a n g e s o f B.E.T. A r e a s on B e a t e n  Workers  B.E.T. A r e a s Unbeaten  pulp  Samples  (sq.m./g.)  Heaviest beaten pulp  range  Thode e t a l  100  202  100 - 202  Stone and S c a l l a n  130  170  130 - 170  G r o t j a h n and Hess  184*  195  178 - 207  T h i s work  193  161  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 a n d t h e S t o n e a n d Scallan  surface areas f o r unbeaten pulp are c o n s i d e r a b l e  less  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 a n d H e s s o r d e t e r m i n e d i n t h i s work.  I f some o f t h e p o r e  c o l l a p s e d d u r i n g solvent- exchange  * beaten  slightly  structure  d r y i n g , as i t a p p a r e n t l y  does  -135-  because o f the l a r g e d i s c r e p a n c y 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  w e l l expect p u l p s p r e p a r e d by d i f f e r e n t c h e m i c a l t o c o l l a p s e d i f f e r i n g amounts.  T h i s may  may  treatment  be the r e a s o n  unbeaten k r a f t p u l p o f t h i s study has a s i g n i f i c a n t l y  the  higher  B.E.T. s u r f a c e a r e a than the s u l p h i t e p u l p s 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 s u r f a c e  a r e a s o f the d i f f e r e n t p u l p s have comparable s u r f a c e a r e a s . F i g u r e 42 shows the change i n a r e a w i t h m o i s t u r e c o n t e n t p r i o r t o s o l v e n t exchange d r y i n g f o r t h i s work and t h a t o f Stone and S c a l l a n (16). comparison,  I n o r d e r t o have a d i r e c t  the s u r f a c e a r e a s are reduced t o a common b a s i s  by d i v i d i n g the e x p e r i m e n t a l a r e a s by the a r e a found f o r the s o l v e n t exchange d r i e d f u l l y water  swollen pulp.  Table  18 l i s t s these d a t a . As t h e r e i s a r e a s o n a b l e agreement between the s e t s o f d a t a , the c o n c l u s i o n s of Stone and S c a l l a n (16) substantiated.  The  two are  c o n c l u s i o n i s t h a t v e r y l i t t l e happens on  d r y i n g from h i g h m o i s t u r e c o n t e n t s u n t i l about e q u a l p a r t s water and f i b r e are r e a c h e d .  At t h i s p o i n t , the  pore  volume, and hence the s u r f a c e a r e a , s t a r t s t o decrease  and  c o n t i n u e s t o decrease t o z e r o m o i s t u r e , at which p o i n t the volume has been reduced v i r t u a l l y t o z e r o .  pore  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 o f 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 t o  develop  s i g n i f i c a n t l y at about 50 p e r c e n t s o l i d s ( e q u a l 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  -136-  PERCENT  MOISTURE  -137-  Table 1 8 :  Dependence o f S u r f a c e Area on M o i s t u r e Content.  Percent Moisture  Area (sq.m./g)  Area Area o f S a t u r a t e d Sample  Stone & S c a l l a n ( 2 0 ) 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  T h i s 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  -138tensile  s t r e n g t h i n a wet  i n the pore C.  Pore  web  i s accompanied  by a d e c r e a s e  volume.  Analysis The  significantly  p o r e v o l u m e and p o r e a r e a d i s t r i b u t i o n s a f f e c t e d by t h e g e o m e t r i c m o d e l a s s u m e d .  is  shown i n f i g u r e s  in  s e c t i o n IV-C.  43 and  44.  T h i s e f f e c t was  H o w e v e r , as t h e d i f f e r e n c e s  and p o r e a r e a d i s t r i b u t i o n s  i n figures  discussed  44  a r e due  of p h y s i c a l  s u c h as b e a t i n g , on t h e p o r e v o l u m e and p o r e a r e a tributions will  be s i m i l a r  f o r t h e two m o d e l s .  t h e f o l l o w i n g d i s c u s s i o n , t h e p o r e shape t o be t h a t o f a p a r a l l e l  sided  fissure  c a l c u l a t i o n method o f P i e r c e  a p p l i c a b l e to the p a r a l l e l m o d i f i e d m e t h o d was  (48)  This  i n the pore  43 and  c a l c u ] a t i o n a l d i f f e r e n c e s , the e f f e c t s  The  are  volume to  parameters, disThroughout  has b e e n assumed  unless otherwise noted. was  m o d i f i e d t o be  s i d e d f i s s u r e m o d e l and  this  used f o r a l ln i t r o g e n d e s o r p t i o n  iso-  therms. The lative  v a l u e s o f t h e c u m u l a t i v e p o r e v o l u m e and  p o r e a r e a a r e a f f e c t e d by t h e r e l a t i v e  which the c a l c u l a t i o n begins.-  T a b l e 19  cumu-  p r e s s u r e at  i s a comparison  the values of these v a r i a b l e s determined from a n i t r o g e n sorption isotherm of solvent p u l p u s i n g two  different  exchange  d r i e d unbeaten  T a b l e 19  shows t h a t by  the r e l a t i v e p r e s s u r e at which the c a l c u l a t i o n begins t o 0.95,  one  changes  I65.9 m i s . ( S . T . P . ) / g . . a n d f r o m 122.3  t o 116.8  de-  wood  v a l u e s of r e l a t i v e p r e s s u r e at the  beginning of the c a l c u l a t i o n .  0.90  of  changing from  t h e t o t a l p o r e v o l u m e f r o m 150.3 a l s o changes  s q . m./g.  the t o t a l pore  These changes  to  area  a r e m a i n l y due  to  -138a-  the d i f f e r e n t . s u r f a c e a r e a assumed i n the  calculational  method when  gas  allowing  from the a d s o r b a t e if  adsdrbed  there i s s i g n i f i c a n t  (ie  " e x t e r n a l " surface area  mis.  volume changes the  (S.T.P. )/gm.  to 123.8  2.5  and  percent pore  a f t e r the i n i t i a l  present ) the  the r e s u l t s  i n the i n i t i a l  value of  are the  volume from 150 .3 t o  155.9  changes the t o t a l pore a r e a from  122.3  sq.m./gm. Most o f these  e r r o r as e v i d e n c e d  w a l l s . Thus  o f v e r y l a r g e pores  method does not a l l o w f o r i t and  e r r o r . An e r r o r o f  adsorbed  desorbed  on the exposed pore  the a r e a o f open s u r f a c e s and  calculational in  f o r the volume o f  changes a r e due  directly  t o the  by the s m a l l changes i n the d a t a r e p o r t e d p o i n t . These r e s u l t s i n d i c a t e t h a t  the  pore volume c a l c u l a t i o n s are v e r y s e n s i t i v e t o changes i n the r e l a t i v e errors  p r e s s u r e o f the i n i t i a l  i n the volume  d a t a p o i n t and  a d s o r b e d . Thus , i n o r d e r t o compare  pore volume and pore a r e a d i s t r i b u t i o n s volumes a t s p e c i f i e d isotherm of  p l o t s and  Appendix D l i s t s  to small  r e l a t i v e pressures used f o r the  , the  adsorption  were taken  c a l c u l a t i o n s . Table  from I  t h e r e s u l t s o f the pore a n a l y s i s , on n i t r o g e n  WALL SEPARATION A  -140-  FIGURE  44  CUMULATIVE PORE AREA OF UNBEATEN SOLVENT EXCHANGE DRIED PULP AS DETERMINED BY NITROGEN a ARGON  200  DESORPTION  ISOTHERMS.  175  O NITROGEN (PARALLEL SIDED FISSURE MODEL)  150  A ARGON  E  2 125  •  <  NITROGEN (CYLINDRICAL MODEL)  PORE  UJ  cc < LU 100 cc o o. LU  < -J  2  o  50  25  15  30 WALL  40  50  SEPARATION  60 A  150  200  Tabl-e 19:  E f f e c t o f I n i t i a l Data High relative (P/P v ads. , * Area** 0  p/p  0  P o i n t on Cumulative Pore Volume and Cumulative Pore Area initial Lower i n i t i a l E f f e c t o f 2.5$ e r r o r pressure r e l a t i v e pressure i n i n i t i a l volume = 0.90) 204.4) = 0.95) (P/P = 0.90 Volume*** Area Volume Area Volume  0.950  225.2  0.900  199.4  0.850  181.0  12.3  0.800  164.1  20.5  50.9 69.4  0.750  149 .2  29.5  85-3  0.700  138.4  96.3  0.650 0.600  128.7 120.8  36.9 44.6  0.550  114.1  57.7  0.500 0.480  105.5 90.2  67.1 87.4  0.460  81.4  99.0  144.3 153.4  0.440  76.9  104.6  157.6  0.400  71.5 66.0  110.7 116.8  161.9  109-3 115.8  165-9  122.3  0.350 * **  V  a d s  5.66  51.4  = Volume adsorbed  (v  D  =  30.2  105.9 113-5 119.6 127.8  (mis.  Area = Cumulative pore a r e a  7.51  23.4  16.7  44.2  26.7 35.0  61.9 74.1  43.5 51.0  84.8  9.55 18.7 28.6  29.7 50.3  36.8  67.9 80.1  93.1  45.3 52.8  90.7 99.0  58.0  99.9  59.6  105.6  68.3 90.6  108.9 127.0  69-9 92.1  114.6  103-2  136.9 141.4  104.8  132.7 142.6  110.8  147.1  146.1  117.3 123.8  151.7  150.3  (S.T.P.)/g.) (sq.m./g.)  **'*-• "Volume = Cumulative pore volume ( m i s . (S.T.P. )/g.)  155.9  -142isotherms. using is  the  of a small  point  of the  Argon calculate are  desorption  the pore  m o d e l was  assumed  isotherms. used  The  adsorption  78  could  available for  the  zinc to  at  43  78.1  44.  and  calculation  on  The  the  proposed  of  3-28  ft  extrapolated by  analysis  standardized  relative  Appendix  Table  c a l c u l a t e d from The and  the  as  the  a  a  single  4,  no  desorption  material  by  to  data f o r at  on  the  Rhodin  crystal  adsorbed  (165)  face  of  Appendix  D,  (110).  listed  lists  the  pore  determined  the  method  The  results  isotherms i n Table  the  pore  F.  3  with of  analysis  as  points.  volume  assuming  was  using  desorption  experimental data pore  of argon  Boer  pressures are  onto  1 of Appendix  density  de  argon  analysis,  fissure  "standard" isotherm i n order  bulk liquid  using  results  similar  experimentally  f o r a monolayer  differential argon  19  to  argon  As  isotherm reported  L i p p e n s , L i n s e n and  D.  at  sided  was  cellulosic  onto  used  typical  using  This isotherm i s given i n Table  the pore  nitrogen  and  analysis.  or determined  used  also  technique used  pore  of argon  was  adsorbed  parallel  analysis  a non-porous  found  °K  calculations  shown i n t a b l e  volume  distributions  i n a l l pore  equipment, the  thickness  from  of  volume  adsorption  i n the  e s t i m a t e t h e number o f m o n o l a y e r s  walls. A  be  Also  i s o t h e r m s were  f o r the n i t r o g e n  argon °K  error  these  calculation.  shown i n f i g u r e s  that  D lists  of appendix  experimental data points.  the e f f e c t  initial  2  Table  distributions the p a r a l l e l  of sided  the  -143f l s s u r e model, a r e 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 25ftf 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  fissure  model). The cummulative pore volume d i s t r i b u t i o n s o f a number o f c e l l u l o s i c m a t e r i a l s a r e 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 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 , were reduced t o a common b a s i s by d i v i d i n g by the t o t a l pore volume. i n Appendix C.  The d a t a o f these samples a r e l i s t e d  These samples and a l l o f t h e n i t r o g e n  i s o t h e r m samples i n t h i s work, show a most common pore s i z e o f a p p r o x i m a t e l y 25 ft w a l l s e p a r a t i o n . • T h i s has been i n t e r p r e t e d as b e i n g a b a s i c p h y s i c a l p r o p e r t y o f c e l l u l o s i c materials (8). The most common pore s i z e i s i n d i c a t e d by t h e p o i n t of s t e e p e s t descent on t h e d e s o r p t i o n i s o t h e r m .  The  average v a l u e s o f t h e most common pore s i z e as determined from t h e n i t r o g e n , argon and oxygen d e s o r p t i o n i s o t h e r m s 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 a r e g i v e n i n Table 20. As can be seen i n Table 20, f o r any o f t h e adsorbates 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 p r e s s u r e a t which t h e most common pore s i z e i s found.. The dependence o f t h e most common pore s i z e on t h e a d s o r b a t e used i s s i m i l a r t o t h a t noted by H a r r i s (149, 150) when he was s t u d y i n g microporous ( D u b i n i n d e f i n i t i o n , IV-D) s i l i c a s and aluminas o f narrow pore s i z e  Section  distribition.  H a r r i s found t h a t n i t r o g e n and argon d e s o r p t i o n isotherms; on  A (CUMULATIVE PORE VOLUME) A (WALL SEPARATION)  -trtrl-  fmls (SJ.R)  _j  20  ;  1  25  1  30 WALL  i—  i  40 SEPARATION  50 A  '  60  •  70  I  80  I  I  90 100  -146-  Table 20:  Pore S i z e a t Steepest  Sample D e s c r i p t i o n Moisture Content  Minutes Beaten  Descent on D e s o r p t i o n  Isotherms  R e l a t i v e Pressure at Steepest Nitrogen  Decent  Argon  Oxygen  0.285  (%)  Saturated  0  0.48  0.365  Saturated  0  0.49  0.365  Saturated  1  0.48  0.360  0.285  Saturated  3  0.48  0.355  0.270  Saturated  5  0.  47  0.355  Saturated  10  0.48  0.355  Saturated  10  0.485  0  0.475  0.355  0  0.475  0.355  14.4  0  0.475  33.6  0  0.485  Vacuum dried 5.3  Average Values =  0.480  0.357  Pore S i z e * C y l i n d r i c a l pore  19-0  16.7  P a r a l l e l sided f i s s u r e pore  25.0  21.2  0.270  0.278  14.3  18.6  * The t h i c k n e s s o f a monolayer was c a l c u l a t e d u s i n g t h e method of L i p p e n s , L i n s e n and de Boer (110). The monolayer coverage f o r oxygen was., e s t i m a t e d by comparison o f t h e oxygen i s o t h e r m s with the n i t r o g e n isotherms.  -147t h e s e m i c r o p o r o u s samples, always i n d i c a t e d most common pore s i z e s o f r o u g h l y 18 and 14 A r a d i u s r e s p e c t i v e l y a cylindrical  pore s h a p e ) .  (he assumed  Thus any m i c r o p o r e s p r e s e n t i n s o l v e n t  exchange d r i e d ' c e l l u l o s e would appear on t h e d e s o r p t i o n i s o t h e r m as p o r e s o f t h e most common pore s i z e .  The a p p a r e n t l y  d i f f e r e n t v a l u e s o f t h e most common pore s i z e may w e l l be due t o the or  e r r o r s i n assuming t h e K e l v i n e q u a t i o n i s a p p l i c a b l e , i n assuming t h e number o f monolayers a d s o r b e d , o r i n  assuming t h e t h i c k n e s s p e r these assumptions.  monolayer  o r any c o m b i n a t i o n o f  . The most common pore s i z e s as d e t e r m i n e d  by n i t r o g e n , argon and oxygen  isotherms r e f l e c t  t h e same  p a t t e r n as t h e m o l e c u l a r volumes o f t h e s e a d s o r b a t e s when t h e b u l k l i q u i d d e n s i t y v a l u e s a r e assumed (see t a b l e 2 1 ) . The 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 shown i n f i g u r e 43 a r e e x p r e s s e d as mis o f gas a t 0 °C and one a t mosphere p r e s s u r e , which i s s i m p l y a measure o f t h e number o f molecules r e q u i r e d t o f i l l  the pores.  Some a s s u m p t i o n must  be made as t o t h e volume o c c u p i e d by a s i n g l e m o l e c u l e o f adsorbate.  The a d s o r b a t e m o l e c u l e s a r e u s u a l l y assumed t o  r e t a i n t h e b u l k l i q u i d p r o p e r t i e s and thus t h e volume o c c u p i e d per  m o l e c u l e i s c a l c u l a t e d from t h e b u l k l i q u i d  density.  F i g u r e 47 i s t h e c u m u l a t i v e pore volume f o r t h e s o l v e n t exchange d r i e d unbeaten p u l p 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 i s o t h e r m s and assuming t h e l i q u i d d e n s i t i e s o f t h e adsorbates.  These d a t a aF l i s t e d i n T a b l e 5 , Appendix D. e  T a b l e 21 i s a comparison between t h e m o l e c u l a r volume  cal-  c u l a t e d from b u l k d e n s i t y and t h e van d e r Waals m o l e c u l a r volume ( 1 6 7 ) •  0.25  FIGURE 47 CUMULATIVE  PORE  ADSORBATE 0.20  BULK  EXPRESSED AS  mis  OF  LIQUID FORM.  CALCULATED FROM NITROGEN AND ARGON DESORPTION  CO  ISOTHERMS ON UNBEATEN  E £  IN  VOLUME  S.E.D. PULP  <XI5  3 —I O > £  o  co l  aio  0. Ul  > 0-05 <  -J 3 3 O  O  NITROGEN  A  ARGON  X  20  I  25  WALL  _L  30  -L  35  SEPARATION  ±  40 ( A* )  50  60  JL  70  -L  80  -L  90  100  -149Table 21: M o l e c u l a r Volumes o f A d s o r b a t e s Adsorbates  M o l e c u l a r Volume  cu. angstroms  From d e n s i t y  van d e r Waals  Nitrogen  57.8  25.0  Argon  45.6  20.6  Oxygen  44.6  23.0  The van d e r Waals m o l e c u l a r volume c o u l d be t a k e n as t h e lower boundary f o r t h e p o s s i b l e volume o f t h e a d s o r b a t e i n t h e p o r e . Thus T a b l e 21 i s an i n d i c a t i o n o f t h e wide range o f molec u l a r volumes t h a t c o u l d c o n c e i v a b l y be used t o c o n v e r t t h e number o f m o l e c u l e s  i n t h e pores t o an e s t i m a t e o f t h e  volume o f t h e p o r e s . Throughout t h i s work where t h e a c t u a l pore i s estimated  t h e volume o c c u p i e d by an a d s o r b a t e m o l e c u l e i s  assumed t o be t h e volume o c c u p i e d i n t h e b u l k l i q u i d . assumption  volume  This  o f t h e b u l k l i q u i d m o l e c u l a r volume i s a l s o used t o  c a l c u l a t e t h e t h i c k n e s s o f t h e adsorbed A l l o t h e r workers  surveyed  walls.  ( 2 0 , 46-48, 111-114) a l s o assumed  the m o l e c u l a r volume o f t h e ' a d s o r b e d as t h a t i n t h e b u l k l i q u i d .  l a y e r s on t h e pore  a d s o r b a t e t o be t h e same  Because o f t h e h i g h e r energy o f  a d s o r p t i o n o f t h e f i r s t m o n o l a y e r ( 2 0 ) t h e van d e r Waals m o l e c u l a r volume i s p r o b a b l y a b e t t e r e s t i m a t e o f t h e m o l e c u l a r volume t h a n i s t h e b u l k l i q u i d m o l e c u l a r volume.. However, a f t e r many l a y e r s , the a d s o r b a t e m o l e c u l a r volume must approach  t h a t found i n t h e  b u l k l i q u i d as a sharp t r a n s i t i o n t o t h e b u l k phase i s not probable.  However, as t h e d a t a r e q u i r e d t o p r e d i c t t h e change  i n m o l e c u l a r volume w i t h d i s t a n c e ( o r m o n o l a y e r s ) from t h e adsorbent  s u r f a c e has not been f o u n d , i t was d e c i d e d t o - u s e t h e  - 149 a -  b u l k l i q u i d m o l e c u l a r volume. The 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 figures  47 and 48 show t h e two a d s o r b a t e s p r e d i c t  similar  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 g r e a t e r t h a n 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 o f l e s s t h a n 30 ft. T h i s descrepancy i s due t o t h e d i f f e r e n t v a l u e s o b t a i n e d f o r t h e 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 o f t h e vacuum d r i e d , s o l v e n t exchange culated  d r i e d handsheets as c a l -  from argon and 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 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 g i v e a good  i n d i c a t i o n o f t h e a p p a r e n t l y v e r y l a r g e volume o f pores a t the most common pore s i z e . A comparison between t h 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 o f t h e vacuum d r i e d - s o l v e n t exchange sample and t h e sample solvent, exchange suspension i s a v a i l a b l e i n figure. 5 2 . .  dried  d r i e d from a water  WALL SEPARATION  A  -151-  FIGURE 4 9 DIFFERENTIAL  PORE VOLUME DISTRIBUTIONS OF  SOLVENT EXCHANGE DRIED'VACUUM  DRIED  HANDSHEETS CALCULATED FROM NITROGEN AND ARGON  i 30  ISOTHERMS.  O  NITROGEN  A  ARGON  ^Q^^gFTA-Q  40  50 60  WALL SEPARATION  r/rrQi—t—A  80  A  100  -J  150  At-  200  -152-  The changes  i n the 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 b e a t i n g 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 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 c o n t a i n e d i n t h e s e f i g u r e s i s the r e l a t i v e shape o f the c u r v e s as the a b s o l u t e v a l u e o f t h e s e c u r v e s i s h i g h l y dependent  on the f i r s t  d a t a p o i n t as d i s c u s s e t  above. There i s a much w i d e r 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 t h a n 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 o f 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 the  d i f f e r e n c e may  analysis,  be due t o the method o f c a l c u l a t i o n .  Some o f t h e s e a d d i t i o n a l assumptions a r e : i.  The adsorbed argon i s assumed t o be a s u p e r c o o l e d 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 t h a n the s o l i d which b u l k argon i s at the  experimental temperature.  The p h y s i c a l p r o -  p e r t i e s assumed a r e :  ii.  surface tension  = 14.9 dyne/cm.  density  = 1.452  g./ml.  The i s o t h e r m o f argon a d s o r p t i o n on s i n g l e " c r y s t a l f a c e s o f z i n c (160). i s an a p p r o p r i a t e , s t a n d a r d 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  20  1  25  1  30  WALL  :  1  1—;  40  SEPARATION  50 I  I  60  l  70  I  80  l  I  90 100  FIGURE 51 CUMULATIVE  150  EXCHANGE  PORE  VOLUME  DRIED PULPS  DISTRIBUTIONS BEATEN  CALCULATED FROM ARGON  OF  VARYING  DESORPTION  SOLVENT  AMOUNTS  ISOTHERMS.  125  \  ~ 100  a.  •  to  75LU 2 3 _J O >  UJ  O  UNBEATEN  A  BEATEN  I MINUTE  •  BEATEN  3 MINUTES  V  BEATEN  5 MINUTES  9  BEATEN 10 MINUTES  I I  50  fltr LU  p  <  25  —i 3  3 O  20  25  X  30 35 40 WALL SEPARATION  &  50  60  70  JL  80  90  100  -155-  iii.  I n s p i t e o f t h e apparent disagreement w i t h t h e B.E.T. a r e a s , t h e c r o s s - s e c t i o n a l a r e a o f an adsorbed argon m o l e c u l e i s 13-9 s q . A and t h i s a s s u m p t i o n a l s o is  v a l i d f o r t h e t h i c k n e s s o f an argon  monolayer.  (The t h i c k n e s s o f an argon monolayer i s assumed t o be 3-28ft). The d a t a p r e s e n t e d i n f i g u r e 50 and T a b l e 22 i n d i c a t e a s l i g h t s h i f t o f t h e pore volume d i s t r i b u t i o n toward t h e l a r g e r p o r e s as t h e degree o f b e a t i n g i s i n c r e a s e d .  There i s  a l o s s o f t o t a l pore volume i n t h e p o r e s o f l e s s t h a n 100 ft wall separation with beating.  There i s a s i g n i f i c a n t l o s s o f  pore volume o f t h e most common pore s i z e .  The t o t a l pore  volume and t h e volume o f p o r e s - o f t h e most common pore  size  are  l i s t e d i n T a b l e 23.  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 o f the f i b r e i s a l t e r e d even i n t h e v e r y s m a l l  pores.  The apparent l o s s o f pore volume i n  T h i s e f f e c t would be e x p e c t e d 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 p o r e s be-  tween t h e s h e e t s , as t h i s t y p e o f s t r u c t u r e would have  little  p h y s i c a l r e s i s t a n c e t o t h e l a m i n a r s h e e t s b e i n g s e p a r a t e d by the  mechanical a c t i o n of the beater. T a b l e 23 a l s o p r e s e n t s an i n t e r e s t i n g  between t h e volume o f a monolayer  comparison  ( B . E . T . ) , t h e volume o f pores  d e t e c t e d a t t h e most common pore s i z e and t h e D u b i n i n m i c r o pore volume ( f r o m S e c t i o n VI-E) .  Table. 23 shows t h a t t h e change  w i t h b e a t i n g o f t h e volume o f t h e most common pore s i z e i s g r e a t e r t h a n t h e change o f t h e B. E. T. monolayer volume.  The  -156-  Table  22:  P o r e Volume o f D i f f e r e n t  Sized  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 P o r e Volume i n Pores o f W a l l S e p a r a t i o n  Minutes Beaten  Less than 39.1 a  Moisture Content Percent  Parameter:  Level of Beating  (expressed  39.196.5 a  Detected  Greater than 96.5 ft  as m i n u t e s )  0  Saturated  43.6  40.9  15-5  1  Saturated  43-3  34.4  22.3  3  Saturated  34.2  40.6  25.2  5  Saturated  36.1  37 - 8  10  Saturated  35.7  39.3  Parameter:  Percent Moisture Exchange D r y i n g  0  Content P r i o r t o Solvent  18.2  10.6  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  Saturated  43.6  40.9  15.5  .  dried  25.0  71.2  0  Vacuum  26.1  -157-  change w i t h b e a t i n g o f t h e 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 is  s i m i l a r t o t h e change i n t h e B. E. T. monolayer  volume.  The e f f e c t o f c h a n g i n g t h e m o i s t u r e c o n t e n t o f p u l p s h e e t s p r i o r t o s o l v e n t exchange  d r y i n g on t h e c u m u l a t i v e 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. pore volumes the  The c u m u l a t i v e  o f t h e samples have been "reduced" by d i v i d i n g by  t o t a l pore volume t o enable d i r e c t comparisons t o be made.  These "reduced" v a l u e s a r e l i s t e d i n T a b l e 6 o f 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 t h a t t h e pore volume d i s t r i b u t i o n i s s h i f t e d toward t h e s m a l l e r p o r e s as t h e m o i s t u r e c o n t e n t i s l o w e r e d from s a t u r a t i o n .  However, below some  " c r i t i c a l " moisture content, further reductions i n moisture content 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 back toward  l a r g e r pore s i z e s .  T h i s would i m p l y t h a t as d r y i n g p r o g r e s s e s  from t h e wet s t a t e , a l a r g e r p r o p o r t i o n o f t h e pores o f w a l l s e p a r a t i o n e x c e e d i n g 30 A c l o s e t h a n do pores o f l e s s t h a n 30 A wall separation. of  Below t h e " c r i t i c a l " m o i s t u r e c o n t e n t when.most  t h e 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 t h e pores o f l e s s t h a n 30 A w a l l s e p a r a t i o n .  There i s t h e  p o s s i b i l i t y t h a t w i t h t h e p a r a l l e l s i d e d f i s s u r e model f o r p u l p f i b r e s , t h e w a l l s o f t h e l a r g e r pores move t o g e t h e r forming  smaller pores.  T h i s r e s u l t d i f f e r s from t h e r e s u l t s o f  Stone and S c a l l a n (16) on a s u l p h i t e spruce p u l p .  These  workers found t h a t t h e pore s i z e d i s t r i b u t i o n d i d n o t s h i f t during drying.  Stone and S c a l l a n (16) c a l c u l a t e d  their  Table 23:  Comparison  o f V a r i o u s C a l c u l a t e d Volumes*  B.E.T. Monolayer Volume  Sample  Corrected Dubinin Micropore Volume  Volume o f M o s t Common P o r e  Size  Nitrogen Argon 23.3-27.1 A 1 9 . 5 - 2 1 . 8 ft  T o t a l P o r e Volume Nitrogen  Argon  Unbeaten  45.38  34  32.5  38.3  150.5  161.2  Beaten 1 minute  41.75  29  30.9  38.7  138.2  132.7  Beaten 3 minutes  38.65  29  23.5  30.5  146.2  126.0  Beaten 5 minutes  36.22  30  20.5  28.1  112.1  93.2  B e a t e n 10 m i n u t e s  36.99  27  19.7  23.3  117.1  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 O  —  N>  CUMMULATIVE CM  J>  CR  0 t  PORE *>J  VOLUME 00  U>  O  m  -651-  TI  -160-  median pore s i z e by e q u a t i o n 1 and found i t t o be c o n s t a n t at about 35  ft.  T h i s e q u a t i o n can be shown t o i n d i c a t e  e i t h e r the r a d i u s of a c y l i n d r i c a l pore or the w a l l 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 u l a t e d by e q u a t i o n 1 i s l i s t e d i n Table 24.  The  separation calresults  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 drying. The r a p i d d i s a p p e a r a n c e of the l a r g e r pore s t r u c t u r e s below 33.6$ m o i s t u r e content corresponds w i t h the r a p i d development o f wet t e n s i l e s t r e n g t h as r e p o r t e d by Lyne and G a l l a y (33).  Both of these r e s u l t s are p r o b a b l y due t o the  i n c r e a s e d hydrogen bonding between c e l l u l o s e m o l e c u l e s .  This  hydrogen bonding p r o b a b l y r e s u l t s when the c e l l u l o s e mole-, c u l e s o f d i f f e r e n t s t r u c t u r a l elements o f the f i b r e s (pore w a l l s , f i b r i l s e t c . ) are f o r c e d t o g e t h e r by the h i g h p r e s s u r e s r e s u l t i n g from the s u r f a c e t e n s i o n o f the water meniscus. • T h i s mechanism was p o s t u l a t e d by Campbell (26,27,28) and e l a b o r a t e d by Barkas (32) as a means of e x p l a i n i n g how 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.  the  With the .  p r e s s u r e s 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 o c c u r , 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 c o n t a c t w i t h the water meniscus. The c u m u l a t i v e pore areas of 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 des o r p t i o n i s o t h e r m pore a n a l y s i s are shown i n F i g u r e 44. 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 was assumed t o be 13-9  The  and  p  16.2 ft / m o l e c u l e 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 q u i t e good f o r pores of  -161Table 24:  Median Pore S i z e s as Determined by E q u a t i o n 1.  S o l v e n t Exchange D r i e d from Water S u s p e n s i o n P u l p s unbeaten  36  beaten  1 minute  38*  beaten  3 minutes  48  beaten  5 minutes  42*  beaten 10 minutes  38*  S o l v e n t Exchange D r i e d Prom: water s u s p e n s i o n  36  33.6  % water  32  14.4%  water  21  % water  21  5.3  vacuum d r i e d  The  i s o t h e r m was e x t r a p o l a t e d t o p/p  21  = O.965  -162-  w a l l s e p a r a t i o n o f g r e a t e r t h a n 30 ft, w i t h t h e pore a r e a d e t e r m i n e d by argon a n a l y s i s b e i n g l e s s t h a n t h a t d e t e r m i n e d by n i t r o g e n a n a l y s i s .  The t o t a l pore a r e a f o r t h e argon  a n a l y s i s i s l a r g e r than, t h a t found f o r t h e n i t r o g e n  analysis,  whereas t h e argon B.E.T. s u r f a c e a r e a i s l e s s t h a n t h a t found for nitrogen.  The l a r g e r s u r f a c e a r e a f o r argon i s due i n p a r t  t o t h e most common pore s i z e as d e t e r m i n e d by t h e argon analysis being s i g n i f i c a n t l y  l e s s t h a n t h a t found f o r t h e  n i t r o g e n a n a l y s i s w i t h t h e r e s u l t i n g i n c r e a s e i n apparent s u r f a c e area, f o r each u n i t o f pore volume.  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 B.E.T. a n a l y s i s a r e compared t o t h e t o t a l pore a r e a s i n t a b l e 25.  '  .  '  The d a t a o f t a b l e 25 show t h a t t h e B.E.T. s u r f a c e a r e a s f o r argon i s o t h e r m s a r e c o n s i s t e n t l y l e s s thanthose  f o r nitrogen  i s o t h e r m s , w h i l e t h e pore areas d e t e r m i n e d from argon d e s o r p t i o n isotherms are c o n s i s t e n t l y g r e a t e r than those determined nitrogen desorption isotherms.  from  The pore a r e a i s always  c o n s i d e r a b l y l e s s t h a n t h a t d e t e r m i n e d by a B.E.T. a n a l y s i s , w i t h t h e l a r g e s t p e r c e n t d i f f e r e n c e s o c c u r r i n g on s h e e t s t h a t were p a r t i a l l y d r i e d p r i o r t o s o l v e n t exchange d r y i n g . A c c o r d i n g t o P i e r c e (48) t h e B.E.T. and pore areas s h o u l d agree t o w i t h i n a few p e r c e n t . significant."external"  However, i f t h e r e were a  ( i . e . non-porous o r l a r g e pored)  surface  a r e a , t h e agreement between t h e two s u r f a c e a r e a s would be poor.  Assuming t h e r e i s a s i g n i f i c a n t " e x t e r n a l " s u r f a c e a r e a ,  the d i f f e r e n c e between t h e pore a r e a and t h e B.E.T. a r e a s h o u l d 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 t h e d i s t r i b u t i o n o f s u r f a c e a r e a below 33-6 p e r c e n t  T a b l e 25:  Comparison Between B.E.T. S u r f a c e Areas and Pore Areas Nitrogen  Sample D e s c r i p t i o n  B.E.T. Area sq.m,/g.  Pore Area 9 6 . 7 ft sq.m./g.  Argon A B  E T — ' ' *  A  B.E.T. r e a sq.m./g.  Pore A r e a 113-5 ft sq.m./g.  p B  E  Q T  r  e  '  A r e a  S o l v e n t Exchange d r i e d (S.E. D. ) :. Parameter:  Minutes Beaten i n P.F.I. M i l l  Unbeaten p u l p  193.4  113.7  0.588  177.4  145. 6  0 .821  Beaten 1 minute  182.0  113.2  0.622  163.5  125. 5  0 .768  Beaten 3 minutes  168.5  104. 8  0.622  153.5  114. 6  0 .747  Beaten 5 minutes  157-8  88.6  0.561  143.2  92. 3  0 .645  Beaten 1 0 minutes  161. 3  83.0 -  0.515  143. 2  92. 7  0 .647  Parameter:  P e r c e n t M o i s t u r e P r i o r t o S o l v e n t Exchange D r y i n g  Vacuum d r i e d sheets  5.17  1.  Sheets w i t h : 5 . 3 % moisture  7.31  14.4  0.327  4.90 •  2.  60  0 .531  2.98  0.408  7.20  3. 95  0 ,. 5 4 9  0.386  69  % moisture  22.3  8.6  3 3 . 6 % moisture  122.7  82.9  O.676  193.4  113.7  0.588  Saturated  177.4  "  145. 6  0 .821  1  M C7\  LAJ 1  -164moisture indicates  t h e pore area l o s s  drying occurs at a p r o p o r t i o n a l l y in  the "external"  surfaces.  due t o p o r e  higher rate than loss  Emerton  (168) s t a t e d t h a t  increased the external surface area. t h e r e i s no s i g n i f i c a n t indicate  a change,  significant  change w i t h b e a t i n g .  i t I s not possible  The  to  The a r g o n i s o t h e r m s  accessibility  spruce k r a f t  as C a l c u l a t e d f r o m  Accessibility  d a t a o f S t o n e a n d S c a l l a n (69)  p u l p o f 44.6 p e r c e n t y i e l d  i s compared  solvent ex53-  c u r v e s a r e r e d u c e d t o a t o t a l p o r e v o l u m e o f 1.0 r e d u c t i o n i s r e q u i r e d because  This  times the  t o t a l p o r e volume o f t h e n i t r o g e n a d s o r p t i o n d a t a .  54.  T h e s e two f i g u r e s  v o l u m e o f p o r e s a t t h e most common p o r e ( c y l i n d r i c a l p o r e s assumed) o r 25 A w a l l f i s s u r e model assumed), data.  significant  Also, the a c c e s s i b i l i t y  Einstein-Stokes  which i s a b a s i c part  size  show t h a t t h e l a r g e  size,  35 A d i a m e t e r  separation  (parallel  i s not observed i n the access-  volume of' p o r e s below  The 2),  A com-  o f t h e r e d u c e d d i f f e r e n t i a l pore volume w i t h pore  shown i n f i g u r e  ibility  Both  t h e t o t a l pore volume o b t a i n e d  from t h e 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  sided  ofthe  t o say t h e r e i s a  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  is  beating  the r e l i a b i l i t y  t h e c u m u l a t i v e p o r e volume o f t h e unbeaten  parison  of area  change.  D. P o r e Volume D i s t r i b u t i o n s and Gas A d s o r p t i o n D a t a .  on b l a c k  v/ith  With the n i t r o g e n isotherms,  b u t when one c o n s i d e r s  argon pore a n a l y s i s ,  collapse  d a t a do i n d i c a t e a  t h e most common pore' s i z e .  ( o r Stokes) equation (equation  of the a c c e s s i b i l i t y  method,  relates  PORE SIZE  11)  T  FIGURE 54 DIFFERENTIAL  PORE  BY ACCESSIBILITY  9 10  •30 PORE  40 SIZE  AS  DETERMINED  AND GAS ADSORPTION  ACCESSIBILITY KRAFT  VOLUME  DATA  ON  BLACK  SPRUCE  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)  50 (*)  60  80  100  150  200  300  -167the diameter, o f t h e s o l u t e , molecules, t o t h e d i f f u s i o n c o e f f i c i e n t o f t h e s o l u t e , i n the. s o l v e n t and the. v i s c o s i t y of t h e s o l v e n t .  I t i s v a l i d only f o r l a r g e 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 o f d i l u t e  solution  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 entanglement) between s o l u t e m o l e c u l e s .  The d e x t r a n and o t h e r mole-  c u l e s used by Stone and S c a l l a n (69) as m o l e c u l a r probes a r e p o l y s a c c h a r i d e s as i s c e l l u l o s e s a c c h a r i d e ) (see Table 12).  ( t h e g l u c o s e i s a mono-  The s i t u a t i o n where t h e  s a c c h a r i d e m o l e c u l a r probe molecules another  d i f f u s e i n t o pores o f  s a c c h a r i d e ( c e l l u l o s e ) p r o b a b l y negates t h e  assumption o f d i l u t e s o l u t i o n as t h e r e 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 t h e s o l u t e molecules c e l l u l o s e molecules.  and t h e s o l i d phase  Thus, i t i s d o u b t f u l i f t h e E i n s t e i n -  Stokes e q u a t i o n i s a p p l i c a b l e f o r s a c c h a r i d e s d i f f u s i n g  into  pores o f m o l e c u l a r p r o p o r t i o n s i n t h e 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 , t h e r e i s evidence  t h a t t h e v i s c o s i t y o f water  i s i n c r e a s e d when i n near c o n t a c t w i t h a s o l i d s u r f a c e thus changing equation.  (170),  one o f t h e parameters o f t h e E i n s t e i n - S t o k e s  With t h e 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 a l l o w a n c e  has been made f o r t h e water t h a t i s adsorbed and p o s s i b l y hydrogen bonded t o t h e w a l l s o f t h e c e l l u l o s e The  pores.  s u r f a c e a r e a o f t h e pores 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 method on t h e 44.6$ y i e l d k r a f t b l a c k spruce i s about 900-1000 sq.m./g. i f one assumes a p a r a l l e l s i d e d f i s s u r e pore shape.  T h i s i s v e r y l a r g e as t h e t o t a l s u r f a c e a r e a o f a  gram o f i n d i v i d u a l c e l l u l o s e m o l e c u l e s 1400  sq.m./g.  (15).  i s e s t i m a t e d t o be  -168A K e l v i n pore used  i n this  possible  analysis  w o r k h a s many  sources  close  agreement  from a P i e r c e (assuming than be  used  for  a parallel  fissure  The  error,  and t h e  data  isotherm  shape) f o rpores  sided  larger  fissure  53 a n d 54 i n d i c a t e t h e v e r y  found  by n i t r o g e n  (parallel  sided  fissure  the  accessibility  method  (149) ( S e c t i o n  pores  appeared  as.if  were p o r e s  pore  o f 18 ft r a d i u s  pore  o f 25 ft w a l l  with  a wall  exist  perimental  with  model  separation  but are a r t i f a c t s technique  that  techniques  pore with  volume  of less than  to a parallel  Thus,  of pores  A  25 ft a p p e a r a t 25 ft w a l l  18  A  cylindrical  sided  fissure that  pores  a s 25 ft s i z e d separation  adsorption  pore volume  by  de-  i t i s probable  of the nitrogen  of determining  at  distribution.  nitrogen  o f 18 A r a d i u s .  of less than  volume  large  shape) a r e not detected  radius  i s equivalent  separation.  and t h e l a r g e  pore  IV-H) found  isotherms, they  adsorption  of determining  sorption  not  data  the parallel  of pores  A  pores  of probable  desorption  pore  i t .  may w e l l b e f o r t u i t o u s a n d c a n n o t  supporting  figures  25.  Harris  sided  with  i n s e c t i o n IV-C.  sources  of a nitrogen  analysis  shape. Both  volume  o f t h e many  separation,  as e v i d e n c e  pore  associated  f o rthe accessibility  analysis  30 A w a l l  assumptions  of error are discussed  Thus, because the  as t h e Pierce  such  do  ex-  distributions.  - 168 a E.  Dubinin As  and  Pore  Analysis  t h e P i e r c e pore  the accessibility  exchange the  dried  decision  data  cellulose  The D u b i n i n  of measuring  t h e volume  The  Dubinin  the  literature  theory  Dubinin  to  pores  that  (133)  i s above  from  the v/v of the "standard" m  of  the experimental  appendix is  P.  The l o w e r  t o break  common p o r e  limit  sq.m./g.  15.  i ti s necessary  This  type  o f a was  at the relative i s listed  f o rthe size  the Kelvin  25 ft w a l l  sample  of intermediate  The v a l u e  pore  i n table  analysis limit  taken  pressure ^  of intermediate  down, t h a t i s , a t t h e u p p e r  size,  of a  The c o r r e c t e d a d s o r p t i o n  isotherm  datum p o i n t .  assumed t o be where  begins  50  equation  as  sample.  A search of  analysis  i f the area  surface area.  are calculated  as a method  attempted.  stated that  o f a sample  these  i n a microporous IV-P.  solvent  definition)  about  has been proposed  a Dubinin  had n o t been  indicated  (Dubinin  more  i s discussed i n section  c o r r e c t f o rt h i s  values  contains micropores  analysis  of Harris et a l  and S c a l l a n  o f micropores  indicated  as c e l l u l o s e  sized  o f Stone  t h e work  w a s made t o t r y t o d e t e r m i n e  micropores.  such  analysis,  2, pores  apparently  o f t h e most  s e p a r a t i o n o r 19 ft r a d i u s .  -169The indicates  P i e r c e pore  analysis of the preceeding section  t h e s u r f a c e area 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 s a m p l e s o f t h e s o l v e n t e x c h a n g e  dried  wood p u l p .  Estimates  s i z e d pores  f o r t h e samples u s e d i n t h i s work a r e t a k e n  the P i e r c e pore The  o f the surface area o f the intermediate  a n a l y s i s and a r e l i s t e d  from  i n t a b l e 26.  "standard" i s o t h e r m used f o r t h e Dubinin  plot  c o r r e c t i o n s was t h a t o f Payne a n d 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 .  This "standard"  isotherm  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 ] p 11 2  t  = 5.3)  A q u a d r a t i c e x t r a p o l a t i o n was u s e d 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 b e l o w 0.005. "standard" isotherm i s l i s t e d Satisfactory on  cellulosic  Attempts  i n Table  "standard" isotherms  t o determine  such  2 o f A p p e n d i x F.  f o r n i t r o g e n , argon  m a t e r i a l s were n o t f o u n d isotherms  The  and oxygen  i n the l i t e r a t u r e .  by e x p e r i m e n t  on r a 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 . Table pores pore The  26 i n d i c a t e s t h e a r e a o f t h e i n t e r m e d i a t e  i s q u i t e s e n s i t i v e t o t h e shape assumed. m o d e l on t h e c o r r e c t e d D u b i n i n p l o t  size  The e f f e c t o f  i s shown i n F i g u r e 55-  data points f o r the corrected Dubinin p l o t s t o the r i g h t  o f t h e v e r t i c a l dashed l i n e  indicating the limit  of "standard"  i s o t h e r m v a l u e s a r e 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 a r e 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 . d e e s 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  F i g u r e 55  to the  -170-  Table 26: Area o f Pores Above 25.2 ft W a l l S e p a r a t i o n o r 21.2 ft Diameter ( N i t r o g e n I s o t h e r m s ) .  Sample D e s c r i p t i o n Water Content  Minutes Beaten  Area Assuming Parallel Sided F i s s u r e Model sq.m./g.  Area Assuming Cylindrical Pores sq.m./g.  Suspension  0  68,.1 65..1  116..2 110,,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  i  UNCORRECTED  i—  1  PARALLEL SIDED FISSURE MODEL \ I CYLINDRICAL MODEL  10  8  (L06 (p*/p)) l0  2  12  14  16  -172-  model assumed f o r the shape of the p o r e s . of  The  sensitivity  the D u b i n i n a n a l y s i s t o e r r o r s i n the a r e a o f t h e  mediate s i z e d pores i s shown i n F i g u r e 56. 56 t o F i g u r e 55 i t I s apparent  inter-  Comparing F i g u r e  t h a t the e r r o r s i n t r o d u c e d by  e r r o r s i n the measurement o f the s u r f a c e a r e a are s m a l l compared t o those i n t r o d u c e d by assuming an improper  model.  The 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 p u l p s o f v a r y i n g m o i s t u r e c o n t e n t p r i o r t o s o l v e n t exchange d r y i n g were used i n c a l c u l a t i n g corrected Dubinin p l o t s . f i s s u r e model was  assumed.  are shown i n F i g u r e 57.  The The  The p a r a l l e l s i d e d  r e s u l t s of these  calculations  data p o i n t s using 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 d a t a have been o m i t t e d i n F i g u r e 57.  The  c a l c u l a t e d d a t a p o i n t s are l i s t e d i n Table 1 o f Appendix G. The u n c o r r e c t e d D u b i n i n P l o t s o f the same d a t a are shown i n F i g u r e 58.  The  i n t e r c e p t s determined  from the d a t a i n  F i g u r e s 57 and 58 are g i v e n i n Table 27-  The  uncorrected  D u b i n i n d a t a p o i n t s are l i s t e d i n Table 2 o f Appendix G. The  d a t a i n Table 27 i n d i c a t e t h a t even f o r a  sample w i t h a s m a l l s u r f a c e a r e a due  to intermediate size  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 c o r r e c t e d D u b i n i n p l o t s i s a s i g n i f i c a n t percentage v a l u e o f the i n t e r c e p t .  Thus f o r samples such as  pores,  un-  o f the cellulose,  the c o r r e c t i o n f o r the a r e a o f the i n t e r m e d i a t e 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 i n t e r m e d i a t e pore size area.  T h i s f i n d i n g i s c o n t r a r y t o . t h e c o n c l u s i o n of  D u b i n i n ( 133)  who  s t a t e d a c o r r e c t i o n was  a r e a of I n t e r m e d i a t e s i z e d pores was The  not r e q u i r e d i f the  l e s s than 50 sq.m./g.  s e n s i t i v i t y of the D u b i n i n p l o t i n t e r c e p t t o the  FIGURE 56 SENSITIVITY TO AREA OF PORES> 26  A SEPARATION  UNBEATEN SAMPLE  O O  ESTIMATED INTERMEDIATE PORE AREA - 10  PERCENT  + 10 PERCENT i  M -J I  6  8 (UOG  |0  10 (po/p)?  12  (LOG ( / p ) ) IO  P o  2  FIGURE 58 DUBININ PLOTS OF NITROGEN ADSORPTION ISOTHERMS (UNCORRECTED) PERCENT MOISTURE PRIOR TO S.E. DRYING AS PARAMETER  SATURATED  14.4% (LOG (po/p)r ro  VACUUM DRIED  Table 27:  I n t e r c e p t Values f o r Corrected  and U n c o r r e c t e d  Nitrogen  Dubinin  Plots with  Moisture  Content as V a r i a b l e Moisture content of sample (%)  Intercept uncorrected  log^x  Intercept mis. N (S.T.P.) uncorrected corrected 2  corrected  Intercept % Change mis. l i q u i d N for uncorCorrection rected corrected 2  Area o f Intermediate s i z e pores  Saturated  1. 69  1.52  49  33  0.076  0.051  49  66.6  33.6  1. 45  1.33  28  21. 4  0.044  0.033  32  36.0  14.4  0.75  0.72  0.0087  0.0081  5.6  5.2  7.7  1.02  i i— —j 1  5.3 Vacuum dried  0. 27  0.24  1.86  1.8  0.0029  0.0028  0.10  0.06  1.26  1.15  0.0020  0.0018  4.5 10  0. 56 0.42  I  -177-  c o r r e c t i o n f o r the a r e a of the I n t e r m e d i a t e  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 t o s o l v e n t exchange drying.  T h i s r e f l e c t s the f i n d i n g o f the pore a n a l y s i s o f  the p r e c e e d i n g  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 t o s m a l l e r pore s i z e s w i t h d r y i n g . volume i s e s t i m a t e d  The  microporous  assuming the b u l k l i q u i d d e n s i t y a p p l i e s  f o r the a d s o r b a t e m o l e c u l e s i n m i c r o p o r e s .  The e f f e c t s  o f b e a t i n g on the i n t e r c e p t o f the c o r r e c t e d D u b i n i n are shown i n T a b l e T a b l e 28:  The  28.  E f f e c t of B e a t i n g on C o r r e c t e d D u b i n i n  Minutes beaten  Intercept  Micropore mis.  liquid N  2  Analysis  Volume 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 d a t a o f T a b l e 28 and liability  plot  o f the measurement, and  c o n s i d e r i n g the r e -  a s s u m p t i o n s i n v o l v e d , the  c l u s i o n i s t h a t the m i c r o p o r e volumes of the samples are s i m i l a r , w i t h a s l i g h t t r e n d t o lower volumes w i t h h i g h e r of b e a t i n g . apparently  The  s i g n i f i c a n t conclusion i s that there  micropores  present.  are  con-  very levels  Table  29: U n c o r r e c t e d  Dubinin P l o t  Sample Moisture —eontent  Intercepts  Nitrogen  Minutes Beaten  log 1 0 :  (%)  x  Volume gas*  Argon Volume  log ;  liquid**  io  x  Volume  Oxygen Volume  gas*  liquid**  log  1 Q  x  Volume gas*  Volume liquid**  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  Saturated  5  1. 62  42  0.065  1. 72  52.  0.064  Saturated  10  1. 62  42.  0.065  1. 69  49-  0.060  Vacuum dried  Unbeaten  0. 10  1.26  0.0020  0. 18  1.5  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  Volume o f gas g i v e n as mis.(S.T.P.)/g.  *  Volume o f l i q u i d adsorbate  —q CO 1  0.21  1.62  0.044  *  ji  g i v e n as mi's./g. ( b u l k ' l i q u i d d e n s i t i e s  assumed)  0.0019  -179-  U n c o r r e c t e d 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 unbeaten p u l p s o l v e n t exchange d r i e d from a water s u s p e n s i o n a r e shown i n F i g u r e 59.  As t h e  n i t r o g e n D u b i n i n p l o t has a s m a l l e r s l o p e i n t h e l i n e a r p o r t i o n than  do argon o r oxygen, t h e e x t r a p o l a t i o n t o determine the  i n t e r c e p t s h o u l d be more r e l i a b l e .  The lower s l o p e o f t h e  D u b i n i n 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 a t low coverages i s more e n e r g e t i c than argon o r oxygen a d s o r p t i o n .  The h i g h e r  a d s o r p t i o n v a l u e s a t low r e l a t i v e p r e s s u r e s i s d i r e c t  evidence  of t h i s . The  e f f e c t o f b e a t i n g o f t h e p u l p s on t h e u n c o r r e c t e d  argon and oxygen a d s o r p t i o n D u b i n i n p l o t s i s s i m i l a r t o t h a t shown i n F i g u r e 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 o f  the u n c o r r e c t e d D u b i n i n p l o t s a r e g i v e n i n T a b l e 29.  Also  g i v e n i n Table 29 a r e t h e e f f e c t s o f s o l v e n t exchange d r y i n g o f p u l p s from v a r i o u s m o i s t u r e c o n t e n t s on t h e u n c o r r e c t e d Dubinin plot  intercepts.  The volumes t a b u l a t e d i n T a b l e s 27, 28 and 29 r e p r e s e n t t h e number o f m o l e c u l e s r e q u i r e d t o f i l l To c o n v e r t t h i s number o f m o l e c u l e s  the micropores.  t o an e s t i m a t e o f t h e m i c r o -  porous volume r e q u i r e s the i n t r o d u c t i o n o f a v a l u e f o r t h e volume o c c u p i e d p e r m o l e c u l e . micropores  E s t i m a t e s o f t h e volume o f  assuming b u l k l i q u i d d e n s i t y a r e g i v e n i n t a b l e 29-  T a b l e 21 g i v e s an i n d i c a t i o n o f t h e p o s s i b l e range o f v a l u e s t h a t may be assumed. The  d a t a o f Table 29 f o r m i c r o p o r o u s  volumes, assuming  b u l k 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 t h e m i c r o p o r e s , show v e r y good agreement on a l l samples r e g a r d l e s s o f t h e gas adsorbed.  FIGURE 59 DUBININ  PLOTS ON  OF  NITROGEN,  SOLVENT  ARGON  AND  EXCHANGE DRIED  OXYGEN  UNBEATEN  o  NITROGEN  V  ARGON  •  ADSORBTION  ISOTHERMS  PULP  OXYGEN i  i—  1  oo o I  t  1.2-  o o  <L06 (p /p»' ( f t  o  2.4  FIGURE 6 0 DUBININ PLOTS OF NITROGEN ADSORPTION WITH  ISOTHERMS  MINUTES PEL MILL BEATING AS PARAMETER  20  o A  1.6  UNBEATEN I MIN.  o  3 MIN.  9  5 MIN.  V  10 MIN. 1  1— 0 0 1— 1  1  1  >  1.21  o o  oA V  ©  v  A  o  0.8  o 0.4J  8 (L0G ( ,/p))2 |O  P<  10  12  14  16  -182Whether t h i s agreement i s f o r t h e microporous volume o r t h e s u r f a c e a r e a as proposed by t h e Kaganer t h e o r y ( S e c t i o n IV-G) i s unknown.  At t h e p r e s e n t , t h e means a r e not a v a i l a b l e  t o determine w h i c h , i f e i t h e r , o f t h e two o p t i o n s i s c o r r e c t . F. Kaganer S u r f a c e Area D e t e r m i n a t i o n A c c o r d i n g t o Kaganer's t h e o r y ( S e c t i o n I V - G ) , t h e 2 i n t e r c e p t o f the p l o t of l o g x versus ( l o g ( p / p ) ) 1 Q  1 Q  Q  (from  e q u a t i o n 16) r e p r e s e n t s t h e a d s o r b a t e r e q u i r e d f o r a monol a y e r coverage o f t h e a d s o r b e n t .  Table 31 has a comparison  between t h e s u r f a c e a r e a d e t e r m i n e d by t h e B.E.T. method and the Kaganer method. The s u r f a c e areas o b t a i n e d form t h e Kaganer  analysis  are s i g n i f i c a n t l y above those o b t a i n e d from a B.E.T. a n a l y s i s . The agreement between t h e s u r f a c e areas determined by t h e d i f f e r e n t a d s o r b a t e s on t h e v a r i o u s 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 t h e Kaganer a n a l y s i s than f o r t h e B.E.T. a n a l y s 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 a r e a was determined from equation 4 using the bulk l i q u i d density.  The Kaganer  surface  areas r e f l e c t t h e same t r e n d s as t h e B.E.T. s u r f a c e a r e a s , 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 t h e volume adsorbed onto t h e t e s t adsorbent  t o t h e volume adsorbed onto a non-porous r e l a t i v e pressure. on a non-porous  Thus i t i s n e c e s s a r y t o have an i s o t h e r m  adsorbent as a " s t a n d a r d " .  have t h e non-porous test material.  " s t a n d a r d " a t t h e same  I t i s desirable to  adsorbent c h e m i c a l l y i d e n t i c a l t o t h e porous  S e v e r a l attempts were made t o determine an  - 1 8 3 -  adsorptlon Isotherm cellulose  on a n o n - p o r o u s m a t e r i a l s i m i l a r  ( r a y o n , c e l l o b i o s e ) , but  an i s o t h e r m o f s u f f i c i e n t to  the  inability  small areas  these  reliability.  failed  to  produce  T h i s f a i l u r e was  o f the a d s o r p t i o n equipment t o measure  involved.  Thus t h e d e c i s i o n was  isotherm.  porous alumina and  de B o e r  Two  and  ( 1 1 0 ) ;  literature:  P a y n e and  of the  "t"-plot  to the  figure  6l.  standard  The  Sing  "standard"  comparison are  standard  isotherms The  for to  two those  reasons:  metals,  of t h i s  ionic  w e r e aware t h a t t h e i r  crystals,  The  "standard"  F.  S i n g was  de B o e r , and  the r e l i a b i l i t y  isotherm  of the  of these  isotherm  chosen similar  been used  thus  probably  due  checked  isotherms  result  on  in a cellulose  f o r the non-porous adsorbent.  t o one  workers  agree w i t h t h a t  w h i c h 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 p o r o u s  phenomenon c o u l d be  includes  presented.  "standard"  of l e s s than that observed  carbon,  In a d d i t i o n , these  i s o t h e r m d i d not  for  The  isotherm are very  the  as  tabulated values  2 of Appendix  and,  o f L i p p e n s , L i n s e n and  "t"-plot  sensitivity  i s o t h e r m w h i c h has  a wide range of r e l a t i v e p r e s s u r e s .  All  Linsen  f o r a wide range of m a t e r i a l s i n c l u d i n g  o x i d e s and  non-  P i e r c e (48)  i s o t h e r m o f P a y n e and  of the P i e r c e "standard"  as a " s t a n d a r d "  on  2 o f A p p e n d i x H.  i n Table  the values  a  i s o t h e r m u s e d i s shown i n  are g i v e n i n Table  "standard"  The  i s o t h e r m p r o p o s e d by  listed  the  a  Lippens,  ( 1 7 1 ) .  a general isotherm i s also included. this  as  nitrogen adsorption isotherms  are g i v e n i n the  due  made t o use  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 n o n - p o r o u s a l u m i n a standard  to  of the  following:  This  -184-  FIGURE 61  Vv  m  FOR  "STANDARD" ISOTHERM  - 1 8 5 -  (a)  The " s t a n d a r d " i s o t h e r m s g i v e n a r e not a p p l i c a b l e to c e l l u l o s i c  (b)  materials.  The monolayer c a p a c i t y as d e t e r m i n e d equation i s i n error.  by t h e B.E.T.  A l o w e r v a l u e o f t h e monolayer  c a p a c i t y would i n c r e a s e t h e v/v f o r t h e t e s t i s o t h e r m m perhaps by an amount s u f f i c i e n t t o ensure t h a t v / v ^ f o r t h e t e s t i s o t h e r m was never l e s s t h a n t h e corresponding value f o r the standard isotherm. value of v  m  The  would have t o be lowered by about 30 p e r -  cent t o a c c o m p l i s h t h e 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 t h e e f f e c t s  o f b e a t i n g and v a r y i n g m o i s t u r e c o n t e n t on t h e s o l v e n t exchange d r i e d p u l p s .  The " t " - p l o t t h e o r y e n a b l e s one t o d e t e r -  mine a s u r f a c e a r e a from t h e s l o p e o f t h e l i n e a r p o r t i o n o f t h e plot.  T a b l e 30 r e s u l t s from such a d e t e r m i n a t i o n .  The s u r -  f a c e areas as measured by t h e " t " - p l o t method a r e 30-40 p e r c e n t l a r g e r than those measured by t h e B.E.T. t e c h n i q u e .  This  f i n d i n g i s t h e r e v e r s e o f what would be e x p e c t e d from t h e 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 s m a l l e r a r e a t o f o r c e ads o r p t i o n o f t h e porous s o l i d t o remain g r e a t e r than t h a t o f t h e non-porous s o l i d . a d s o r p t i o n space  S t e r i c hindrance  because o f t h e r e s t r i c t e d  i n m i c r o p o r e s would not account  B.E.T. s u f a c e a r e a as these  f o r t h e low  m i c r o p o r e s would be f i l l e d  before  r e a c h i n g t h e r e l a t i v e p r e s s u r e a t which t h e " t " - p l o t becomes linear  (0.02< p/p < 0.45). Q  In a d d i t i o n , the l i n e a r region of  the " t " - p l o t c o n t a i n s t h e range o f a p p l i c a b i l i t y o f t h e B.E.T. equation. One e x p l a n a t i o n f o r t h e h i g h s u r f a c e a r e a measured by  -186-  -.187-  T a b l e 30: S u r f a c e A r e a a s D e t e r m i n e d  by " t " P l o t  Technique  Sample D e s c r i p t i o n Moisture Content prior to S.E.D.  Minutes Beaten  Saturated  Unbeaten  Slope  Intercept  v  m  from  "t*  Plot  . Area "t" Plot Am= 16.2 A  B.E.T. .B.E.T. V Area m 0  60.2 59.8  -20.2  -19.5  60.2 .59.8  262 261  44.28 44.37  193.0 193.4  Saturated  1  55.8  -17.4  55.8  243  41.75  182.0  Saturated  3  51.9  -16.3  51.9  226  38.65  168.5  Saturated  5  44.0  -8.9  44.0  198  36.22  157.9  Saturated  10  51.2  -17.8  51.2  223  37.0  161.3  Vacuum dried  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  5.109  5.11  33.6  Unbeaten  , 28.147  28.15  39.7  . -14.7  39.7  30.6 .  173  the " t " - p l o t i s t h e a p p l i c a t i o n o f t h e Payne and S i n g (171) " s t a n d a r d " i s o t h e r m r e s u l t s i n s e r i o u s e r r o r and i s not a p p l i c a b l e for•cellulosic materials.  P i e r c e noted t h a t i t i s p o s s i b l e  t h a t t h e v/vm v a l u e c a l c u l a t e d f o r h i s s t a n d a r d i s o t h e r m , which 5  i s very s i m i l a r t o t h a t o f Payne and S i n g , may not be t r u e on an a b s o l u t e b a s i s , s i n c e they a r e r e l a t i v e t o t h e volume assumed t o f i l l  the f i r s t  l a y e r o f each sample.  Thus i f t h e  v m c a l c u l a t e d i s i n e r r o r ,' t h e whole s t a n d a r d i s o t h e r m i s I n error. 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 s u r f a c e areas as measured by t h e " t " - p l o t method i s t h a t t h i s method i s not a p p l i c a b l e .  One o f t h e r e q u i r e m e n t  o f 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 condensation  ( i . e . l o s s o f pore a r e a ) throughout  p o r t i o n of the p l o t .  capillary the l i n e a r  Because o f t h e wide d i s t r i b u t i o n o f  pore s i z e s a p p a r e n t l y p r e s e n t i n c e l l u l o s e , i t i s p o s s i b l e t h a t c a p i l l a r y condensation  i s occurring i n some o f t h e m i c r o p o r e s  or s m a l l e r t r a n s i t i o n a l pores throughout the p l o t .  the l i n e a r p o r t i o n of  With some pore s i z e d i s t r i b u t i o n s t h i s  c o u l d i n d i c a t e an a p p a r e n t l y h i g h s u r f a c e a r e a .  effect The range  o f l i n e a r " t " - p l o t s i s between r e l a t i v e p r e s s u r e s o f 0.02 and 0.45.  Reduced " t " - p l o t s ( i . e . a d s o r p t i o n v a l u e s d i v i d e d by the B.E.T. monolayer v a l u e ) 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 are shown i n f i g u r e 6 4 .  I t i s apparent,  t h a t over t h e p r e s s u r e  range o f 0.02 t o 0 . 4 5 these p l o t s may be d e s c r i b e d by a common equation.  Thus, e i t h e r t h e p o r o s i t y o f t h i s wide range o f  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!  0  i  I  0.5  I  1.0  1,5 v/v  0  0.01  OJ  i  0.25 P/Po  2.0  i  2.5  "STANDARD"  0.50  0.75  i  3.0  Table  31:  Comparison o f Surface Areas C a l c u l a t e d by the V a r i o u s Techniques ( a l l s u r f a c e areas a r e expressed as sq.m./g.)  Sample D e s c r i p t i o n  Nitrogen Am = 16.2  Moisture Content  Minutes Beaten  Saturated  Unbeaten  193. 4  236.  Saturated  Unbeaten  193. 0  214.  1  182. 0  214  Saturated  3  168. 5  Saturated  5  Saturated  10  Saturated  Vacuum dried  B.E. T. Kaganer  Argon  Oxy gen A = 12.5 m = - 9 m B.E. T. Kaganer Pore* Kaganer A n a l y s i s B.E.T. A  Pore* A n a l y s i s. P l o t  1 3  261.  177. 4  221.  122.3  262.  170. 1  206.  151.  170.0  202.  110.2  243.  163. 5  221.  132.2  164.5  202.  183.  106.3  226.  153. 5  188.  116.7  153.5  185.  157. 8  183.  84.0  198.  143. 2  199.  93.3  161. 3  183.  86.5  223.  143. 2  184.  98.9  Unbeaten  5. 17  5.5  1.79  7.2  4. 90  5.6  2.81  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.  *  C a l c u l a t e d from n o r m a l i z e d  83.8  isotherms.  173.  I VO  I  5.06  5.5  -192-  T h i s a l s o i m p l i e s t h a t over t h e p r e s s u r e range o f 0.02 t o 0.45 the 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 t h i s wide range o f 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 o n l y as t h e B.E.T. monolayer v a l u e . H. Comparison o f S u r f a c e Areas C a l c u l a t e d by t h e V a r i o u s Techniques While t h e pore a n a l y s i s v a l u e o f t h e pore a r e a i s r e s t r i c t e d t o t h e a r e a o f t h e pores a c t u a l l y d e t e c t e d , t h e B.E.T., Kaganer and " t " - p l o t areas r e p r e s e n t t h e t o t a l a r e a o f the sample a v a i l a b l e t o t h e a d s o r b a t e m o l e c u l e s .  The v a l u e s  r e p o r t e d by t h e v a r i o u s c a l c u l a t i o n a l methods f o r t h e t o t a l a r e a o f any g i v e n sample do n o t agree.  While t h e s e methods  (the B.E.T., Kaganer and " t " - p l o t ) a l l use t h e l o w e r  relative  p r e s s u r e end o f t h e i s o t h e r m f o r t h e i r c a l c u l a t i o n s , t h e 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  o v e r t h e r e l a t i v e p r e s s u r e range o f 0.05 - 0.30; t h e Kaganer a n a l y s i s , 0.0 - 0.05; t h e " 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 t h e B.E.T. and Kaganer s u r f a c e areas  may be due t o micropore The  f i l l i n g a t v e r y low r e l a t i v e p r e s s u r e s .  " t " - p l o t s u r f a c e areas 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  determined  those  by t h e B.E.T. a n a l y s i s , i m p l y i n g t h a t one o f t h e  c a l c u l a t i o n a l t e c h n i q u e s i s i n e r r o r as t h e s e methods u t i l i z e the same r e l a t i v e p r e s s u r e s .  Because o f t h e d i f f i c u l t i e s  a p p l i c a t i o n of the " t " - p l o t technique  i n the  ( d e s c r i b e d above i n  s e c t i o n VI-G) one must assume t h e B.E.T. v a l u e s are more c o r r e c t . A l l o f t h e t e c h n i q u e s f o r e s t i m a t i n g t h e s u r f a c e areas o f t h e p u l p samples r e f l e c t t h e same t r e n d s w i t h changes i n t h e p r e p a r a t i o n o f t h e sample a l t h o u g h t h e r e i s a wide v a r i a t i o n i n the v a l u e s a s s i g n e d f o r any i n d i v i d u a l sample.  The s u r f a c e a r e a  - 192 a -  as d e t e r m i n e d by t h e 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 t h e l o s s o f pore volume w i t h d r y i n g as t h e a r e a o f t h e pore w a l l s d e c r e a s e s f a s t e r t h a n t h e t o t a l a r e a o f t h e samples.  surface  Thus, w h i l e t h e a c t u a l v a l u e o f t h e  a r e a a v a i l a b l e t o an a d s o r b a t e m o l e c u l e i s n o t known, t h e v a r i o u s methods o f p r e d i c t i n g t h e s u r f a c e areas do g i v e reasonable I.  parameters f o r c o r r e l a t i o n s .  P h y s i c a l T e s t i n g o f t h e Handsheets o f t h e E x p e r i m e n t a l  Pulps  Some o f t h e p h y s i c a l t e s t r e s u l t s on t h e handsheets o f the t e s t p u l p s as a f u n c t i o n o f b e a t i n g time a r e l i s t e d i n T a b l e 32 and shown i n F i g u r e 65. F r e e n e s s of- t h e p u l p s .  A l s o l i s t e d i s t h e Canadian S t a n d a r d  The B.E.T. s u r f a c e a r e a o f t h e hand-  s h e e t s was d e t e r m i n e d by n i t r o g e n a d s o r p t i o n on t h e c o n t i n u o u s flow adsorption The  apparatus.  dependance o f some o f t h e p h y s i c a l t e s t  results  of t h e handsheets and p u l p on t h e B. E. T. s u r f a c e a r e a o f t h e handsheets i s shown i n f i g u r e 66. i s apparently  The d e n s i t y o f t h e handsheets  a l i n e a r f u n c t i o n o f t h e B. E. T. s u r f a c e  Table 3 2 :  P h y s i c a l Test R e s u l t s on E x p e r i m e n t a l P u l p s  Sample  Unbeaten  Canadian Standard Preeness (mis.) B.E.T. S u r f a c e Area o f Sheets (sq.m./g.)  728 0.4936 0.4920  Seaten . min.  Beaten 3 min.  Beaten 5 min.  Beaten 10 min.  661  486  308  0.4795  0.4562  0. 4081  0.2994  14  B a s i s weight o f Sheets (g./sq.m.)  60.3  68.8  59.3  63.3  67.8  M o i s t u r e Content (%)  6.26  6.73  6.65  6,68  6.83  0.616  0.630  0 . 674  0.741  41.1  58.0  66.1  70.3  12  12  12  12  2.30  2.63  1.91  5.35  4530  6200  6650  7100  3-32  3.75  3-80  3-9  4.1  4.2  2.9  3.3  3.5  32.0  18.8  16.0  13-0  20  25  25  20  Density  (g./cc)  0.516  B u r s t ( c o r r e c t e d t o b a s i s wt. = 60 g./sq.m.) ( l b . / s q . i n . )  28.4  Number o f T e s t s  13  95 % c o n f i d e n c e l i m i t s  O.98  B r e a k i n g Length (meters) Stretch  (%) Average  2960  3.26  Maximum  3•8  Minimum  3•0  Tear F a c t o r  59-0  *  Number o f Sheets 20 * Some samples s l i p p e d i n t h e 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  -194-  8i  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 MINUTES  6 BEATEN  8  10  -195-  8  028  pIGURE 6 6 PHYSICAL PROPERTIES OF HANDSHEETS AS FUNCTION OF THE B.E.T. SURFACE AREA.  032  0.32  0.40  B.E.T. SURFACE  AREA  0.44  (sq. m./g.)  0.48  0.52  area a f t e r the i n i t i a l density  one m i n u t e o f b e a t i n g , w i t h t h e s h e e t  i n c r e a s i n g w i t h the d e c r e a s i n g s u r f a c e area. An e s t i m a t e o f t h e a r e a o f t h e u n b o n d e d 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 h a n d sheets back t o zero b r e a k i n g l e n g t h . shown i n F i g u r e 66. .52 sq.m./g.  This e x t r a p o l a t i o n i s  The e s t i m a t e d u n b o n d e d s u r f a c e a r e a i s  Using this value i t i s p o s s i b l e t o estimate the  b o n d e d a r e a o f t h e h a n d s h e e t s i f one a s s u m e s t h e u n b o n d e d of thepulps  i sa constant value.  of t h e v a r i o u s handsheets a r e l i s t e d  The e s t i m a t e d b o n d e d  area area  i n T a b l e 33-  T a b l e 33: E s t i m a t e d B o n d e d A r e a s o f H a n d s h e e t s Sample  E s t i m a t e d bonded a r e a s q .m./g.  Inverse of estimated bonded a r e a  Unbeaten  0.025  40  Beaten . f o r 1 minute  0.038  26  Beaten f o r 3 minutes  0.063  16  Beaten f o r 5 minutes  0.110  9.1  B e a t e n f o r 10 m i n u t e s  0.219  4.6  If theresults were l i n e a r l y  of physical tests  o f the handsheets  dependent on t h e e s t i m a t e d bonded a r e a , t h i s d e -  pendence would r e s u l t  i na linear plot  i n F i g u r e 67.  d e n s i t y o f t h e p u l p handsheets has an apparent l i n e a r on t h e b o n d e d a r e a a t h i g h e r b o n d e d The  results  of the beaking  Thus t h e dependence.  areas. l e n g t h , b u r s t and t e a r  factor tests areplotted against the inverse of the estimated b o n d e d a r e a i n F i g u r e 68. these p h y s i c a l t e s t  The r e s u l t s  results arelinearly  v e r s e o f t h e bonded a r e a .  o f F i g u r e 68 i m p l y , t h a t d e p e n d e n t on t h e i n -  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  -197-  FIGURE 67 80  DEPENDENCE  OF PHYSICAL  PROPERTIES  OF  HANDSHEETS ON ESTIMATED BONDED AREA. DENSITY HIO  (cj./c.c.)  70 BREAKING LENGH R i c T  a  (m.)  BURST (Ib./sq.ln.)  60  50  30-  zo  10  6  .05 ESTIMATED  .1  _L  .15  BONDED AREA  .2 (sq.m/g).  .25  -198-  FIGURE 68 SOME PHYSICAL PROPERTIES AS FUNCTION OF THE INVERSE OF THE APPARENT BONDED AREA  ~  0  1  10  _l  20 I  APPARENT BONDED AREA  I  30  J L .  40  -199and  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 w h e r e a s t h e  tear f a c t o r decreases. cremental  In a l l cases, the effect  i n c r e a s e i n bonded a r e a i s l e s s where t h e  b o n d e d a r e a i s l a r g e t h a n where t h e t o t a l small.  The d e c r e a s e  b e c o m i n g more r i g i d  bonded a r e a i s  and t h u s  of the s t r u c t u r e of the sheet  less able to disperse the high  s t r e s s e s c a u s e d by t h e s h e a r i n g a c t i o n o f t h e t e a r  tester. ing  total  i n the value of t e a r f a c t o r with i n -  c r e a s i n g bonded a r e a i s a r e s u l t  local  o f an i n -  The i n c r e a s e i n t h e v a l u e s o f t h e b u r s t a n d  break-  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 t h e a b i l i t y  of the highly  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 sult  i n a failure  of the test  Ingmanson  s t r e s s e s , which would r e -  specimen.  and Thode ( 8 5 )  dependence o f d e n s i t y , t e n s i l e  reported results  %  technique.  i n F i g u r e 67.  s t r e n g t h and  Nordman and G u s t a f s s o n  s c a t t e r i n g technique  found  (82)  that except f o r  s a m p l e s s u b j e c t e d t o l o w wet p r e s s i n g p r e s s u r e s , l i t t l e heavy b e a t i n g ,  a linear relationship  Foreman  (8l),  s t r e n g t h and b o n d e d a r e a .  a light  scattering technique, obtained a l i n e a r  of  s t r e n g t h and l o g ( b o n d e d  also using relationship  area) over a range  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 l o w and v e r y  beaten pulps.  or very  e x i s t s between the  tensile  between the t e n s i l e  bonded  A number o f w o r k e r s  r e l a t i o n s h i p s between t h e t e n s i l e  t h e e s t i m a t e d bonded a r e a . using a light  scattering  on  show a s i m i l a r d e p e n d e n c e on t h e e s t i m a t e d  a r e a as t h e d a t a p r e s e n t e d have p r e s e n t e d  showing the  s t r e n g t h and t e a r f a c t o r  t h e b o n d e d a r e a e s t i m a t e d by a l i g h t Their results  bonded s t r u c t u r e t o  Thus t h e r e i s a p p a r e n t l y l i t t l e  heavily  agreement be-  -200-  tween the v a r i o u s workers s h i p s between apparent  on t h e e x a c t n a t u r e o f t h e  b o n d e d a r e a and p h y s i c a l t e s t  T h i s l a c k o f a g r e e m e n t i s p r o b a b l y due b o n d e d a r e a o f t h e s a m p l e s and f u r n i s h the  samples.  t o t h e assumed  the range  relationresults. un-  o f m a t e r i a l s used  to  -201VII  - CONCLUSIONS  That m i c r o p o r e s might be p r e s e n t  i n s o l v e n t exchange d r i e d  wood p u l p was s u g g e s t e d by the work o f H a r r i s (149) who n o t e d t h a t a d s o r b e n t s h a v i n g an average pore r a d i u s o f l e s s t h a n 18 ft always i n d i c a t e d an average K e l v i n pore r a d i u s o f 18 ft. The c o n c l u s i o n o f t h i s work i s t h a t s o l v e n t exchange d r i e d c e l l u l o s e contains micropores (Dubinin  definition).  T h i s 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 D u b i n i n p l o t t e c h n i q u e m i c r o p o r e volumes. up t o 70 p e r c e n t  f o r the measurement o f  The l a t t e r t e c h n i q u e  i n d i c a t e d that  o f the t o t a l pore volume measured by gas  a d s o r p t i o n would be i n the form o f m i c r o p o r e s .  These a r e  p o r e s , whose r a d i u s i s l e s s t h a n 18ft,i n which enhanced a d s o r p t i o n i s assumed t o o c c u r as opposed t o the 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 .  uniform  Thus the  surface  a r e a 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 . W h i l e gas a d s o 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  a r e a and pore volume d i s t r i b u t i o n o f s o l i d s w h i c h c o n t a i n o n l y macropores and l a r g e r i n t e r m e d i a t e p o r e s , i t i s n o t 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 a d s o r b e n t s which c o n t a i n m i c r o p o r e s such as s o l v e n t exchange d r i e d c e l l u l o s e .  The  f i g u r e s o b t a i n e d i n such cases may be used t o i n d i c a t e t r e n d s o r as parameters t o c o r r e l a t e some p u l p o r paper p r o p e r t y a g a i n s t , but s h o u l d not be used t o measure the a b s o l u t e  size  o f pores which are i n t u r n used t o p o s t u l a t e models o f t h e p h y s i c a l s t r u c t u r e o f c e l l u l o s e o f c e r t a i n dimensions.  This  -202c o n c l u s i o n i s made because t h e c a l c u l a t i o n a l used t o e v a l u a t e the i s o t h e r m s  techniques  are of q u e s t i o n a b l e  and t h e s o l v e n t exchange d r y i n g t e c h n i q u e  validity  a p p a r e n t l y does  not r e t a i n t h e s t r u c t u r e o f t h e w a t e r s w o l l e n p u l p . The c a l c u l a t i o n a l t e c h n i q u e s  f o r the determination of  pore volume a r e i n doubt because a number 120-123, 127-129) have suggested  o f workers  (38-40,  that the p h y s i c a l p r o p e r t i e s  o f t h e l i q u i d a d s o r b a t e , which e n t e r i n t o t h e K e l v i n e q u a t i o n , have d i f f e r e n t v a l u e s i n b u l k l i q u i d s t h a n they do i n pores w h i c h a r e o f a s i m i l a r o r d e r o f magnitude i n s i z e t o t h e . adsorbate  molecules.  w i t h adsorbate of adsorbate  A l s o t h e volume f i l l i n g o f the pores  and the p o s s i b l e s t e r i c h i n d e r a n c e  molecules  i n t o the micropores  to entry  p r e s e n t a r e not  a l l o w e d f o r i n the K e l v i n type pore a n a l y s i s .  The D u b i n i n  method o f 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 for  c e l l u l o s e p r i o r t o t h i s work, does c o n s i d e r t h e volume  f i l l i n g of pores. .Gas a d s o r p t i o n t e c h n i q u e s  f o r determining the surface  a r e a o f a i r d r i e d handsheets a r e a p p a r e n t l y v a l i d as t h e volume o f pores i n t h e s e samples i s so s m a l l t h a t t h e r e i s almost  no pore a r e a t o i n t e r f e r e w i t h t h e a p p l i c a t i o n o f t h e  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 l a r g e volume o f pores a t a p p r o x i m a t e l y  18 ft r a d i u s  o r '25 ft w a l l s e p a r a t i o n d e t e c t e d by s e v e r a l workers u s i n g 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 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 o f H a r r i s (149) ( d e s c r i b e d in  c o n c l u s i o n 2) and t h e a c c e s s i b i l i t y r e s u l t s o f 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 o f pores a t o r n e a r 18 - 25 ft w a l l s e p a r a t i o n . size  Thus t h e most common pore  (18 ft r a d i u s o r 25 ft w a l l s e p a r a t i o n ) i s p o s s i b l y below  the lower 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 and may not e x i s t . P. F. I . m i l l b e a t i n g o f wood p u l p a l t e r s t h e f i b r e s t r u c t u r a l components down t o a t l e a s t t h e l i m i t o f 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 e v i d e n c e d  by t h e de-  c r e a s e i n d e t e c t e d volume o f p o r e s a t and below t h e most common, pore s i z e .  Even w i t h pores o f s i z e s l a r g e r t h a n  the most common pore s i z e , t h e 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 p o r e s , a f i n d i n g c o n t r a r y t o the r e s u l t s o f 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 was  s u r f a c e a r e a o f t h e s o l v e n t exchange d r i e d p u l p s  found t o 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  contra-  d i c t o r y t o t h e r e s u l t s r e p o r t e d by Stone and S c a l l a n (16) and Thode e t a l (54). with beating.  Grotjahn  and Hess (49) r e p o r t e d no change  The magnitude o f t h e s u r f a c e areas  by t h e p r e s e n t work a r e s i m i l a r t o those  reported  r e p o r t e d by G r o t j a h n  and Hess and a r e s l i g h t l y l a r g e r t h a n those r e p o r t e d by Stone and S c a l l a n and a r e c o n s i d e r a b l y l a r g e r t h a n r e p o r t e d by Thode e t a l .  those  The d i f f e r e n c e s a r e p r o b a b l y due  t o two f a c t o r s ; t h e s o l v e n t exchange d r y i n g t e c h n i q u e , and the d i f f e r e n c e s i n t h e p u l p samples used.  -  202  b -  Severe s t r u c t u r a l changes o c c u r when wood p u l p i s a i r d r i e d from a water s w o l l e n s t a t e as i s e v i d e n c e d  by t h e  d e c r e a s e i n pore volume and t h e 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 s m a l l e r p o r e s .  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  c o n t e n t p r i o r t o s o l v e n t 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 c o n t r a r y t o t h e r e s u l t s o f Stone and S c a l l a n (16), who r e p o r t e d t h e r e 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 d e c r e a s i n g m o i s t u r e p r i o r t o s o l v e n t exchange d r y i n g . for t h i s discrepancy  content  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  has been found o t h e r t h a n t h e samples  o f wood p u l p were q u i t e d i f f e r e n t . The content  B. E. T. s u r f a c e a r e a change w i t h d e c r e a s i n g  moisture  p r i o r t o s o l v e n t 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 r e p o r t e d by Stone and S c a l l a n (16) when t h e s u r f a c e areas a r e r e d u c e d t o a common basis.  (The B. E. T. s u r f a c e areas f o r t h e p a r t i a l l y d r i e d  samples were d i v i d e d by t h e B. E. T. s u r f a c e a r e a o f t h e sample s o l v e n t exchange d r i e d from t h e wet s t a t e . ) W h i l e c e l l u l o s e pore s t r u c t u r e s a r e p r o b a b l y  o f complex  shape, t h e p a r a l l e l s i d e d f i s s u r e model p r o p o s e d by Stone and  S c a l l a n d e s c r i b e s t h e r e s u l t s o f t h i s work more  t h a n t h e more commonly used c y l i n d r i c a l pore shape.  adequately  - 202  c -  " t " - 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 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  c o u l d be d e s c r i b e d as a f u n c t i o n o f the B. E. T.  monolayer  c a p a c i t y and the s t a n d a r d i s o t h e r m over the r e l a t i v e range o f 0.02 condensation  t o 0.45.  T h i s i m p l i e s t h e r e i s no  over t h i s p r e s s u r e range.  pressure  capillary  F u t u r e " t " - p l o t work  s h o u l d be based on a nonporous c e l l u l o s i c " s t a n d a r d "  isotherm  i n o r d e r t o e x t r a c t the maximum amount o f i n f o r m a t i o n from t h i s p r o m i s i n g method.  -203-  NOMENCLATURE  A  B. E. T. S u r f a c e Area  A  Cross S e c t i o n a l Area o f an Adsorbed M o l e c u l e ( s q . ft)  m  D K, K  Diffusivity 2  M N  Constants M o l e c u l a r Weight o f Adsorbate  o  Avagadro's b  Number  R  Gas Constant  S  S u r f a c e Area  S„ Qg  S u r f a c e Area Covered by a Monolayer o f t h e Amount o f Vapour Adsorbed a t p / p = 0.08 Q  T  Temperature  V  M o l a r Volume  V  mic  (°K)  Volume o f M i c r o p o r e s i n Sample  (mis.(S.T.P.)/g.)  W  Volume o c c u p i e d by t h e Adsorbed Vapour  c  B. E. T. Constant  k  Constant C h a r a c t e r i z i n g t h e G a u s s i a n D i s t r i b u t i o n o f Surface P o t e n t i a l s Constant  p  P r e s s u r e o f Adsorbate  p  S a t u r a t i o n P r e s s u r e o f Adsorbate a t Temperature o f Adsorption  p/p  R e l a t i v e P r e s s u r e o f Adsorbate  r  Radius o f Pores (ft) K e l v i n Pore Radius (Radius o f V o i d Space i n C y l i n d r i c a l Pore)  r med,  Median Pore Radius  v  Volume Adsorbed  (mis.(S.T.P.)/g.)  -204-  v  Liquid  Q  x x  Amount o f V a p o u r A d s o r b e d  0  x e  x  Volume o f V a p o u r A d s o r b e d  m  965  L  i  c  l i u  d  at p/p  p e r Gram o f  Volume o f V a p o u r A d s o r b e d  at p/p  = 0.90  Q  Adsorbent = O.965  Q  E x p e r i m e n t a l V a l u e 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 Pores Require C o r r e c t i o n f o r Dubinin A n a l y s i s Amount o f A d s o r b a t e  R e q u i r e d t o Form a  Monolayer  a  Value of 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 t h e Nonporous Adsorbent  3  Affinity  Y  Surface  e  Adsorption Potential  n  Viscosity  p  Density  T  Kelvin  (j)  Contact  /  Packing Factor  of  Coefficient Tension at the Liquid-Vapour  Interface  W a l l S e p a r a t i o n ( D i s t a n c e Between Adsorbed Angle  Films)  -205-  LITERATURE CITED 1. 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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 S i n g , K. S. W., Chem. and I n d . , 918-919, (1969) 172. S c a l l a n , A. M., P e r s o n a l Communication.  -214-  APPENDIX A  ISOTHERMS ON UNBEATEN PULP—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  ARGON  NITROGEN JL  p«  P.  0.00014 0.00082 0.00417 0.0125 0.0356 0.0533 0.0842 0.1315 0.1749 0.2130 0.2523 0.2953 0.3390 0.40B2 0.4723 0.5387 0.6004 0.6698 0.7386 0.7094 0.8338 0.8812 0.9356 0.9701 0.9BB1 0.9602 0.9285 0.8823 0.8137 . 0.7597 0.68BO 0.6092 0.5584 0.5152 0.4957 0.4B39 0.4606 0.4237 0.3862 0.3544 0.4583 0.5580 6.6662 0.7597 0.8324 0.6898 0.75B9 0.62B6  0.00440 0.0123 0.0253 0.0482 0.0742 0 . 1245 0.1535 0.1976 0.2314 0.3043 0.3490 0.3935 0.4513 0.5080 0.5606 0.6412 0.70S2 0.7520 6.8137 0.8697 0.9127 0.9395 0.9852 1.0000 0.9*6? 0.8986 0.8785 0.8318 0.7821 0.7185 6.6444 0.5807 0.5148 0.4615 0.4071 0.3762 0.36*6 0.3512 0.3045 0.2356 0.2984 0.3828 0.4764 0.5687 0.6631 0.7597 0.8644 0.9324 0.8710 0.8018 0.7307 0.6520  3.306 8.566 17.33 25.70 33.52 . 37.14 40.98 4 5 . B4 49.63 53.24 56.58 60.62 64.62 71.77 79.40 88.12 97.72 110.84 1*7.30 141.19 155.34 176.09 202.82 228.82 248.76 231.34 214.07 193.76 168.18 151.68  135.01 122.08 115.33 109.62 102.83 93.14  81.71  74.75 70.23 66.60 78.03 91.81  110.20  133.19 155.52 179.86 148.01 123.91  6.00423 0.0267 0.0356 0.0709 0.0933 0.1187 0.1621 0.2155 0.2777 0.3275 0.3878 0.4736 0.5322 0.6257 0.7018 0.7733 0.8171 0.8979 6.9522 0.9716 0.9400 0.B753 0.7B2B 0.7107 0.6763 0.6306 0.5891 0.5392 0.4968 0.4872 0.4743 0.455C 0.4266 0.3880 0.3553  OXYGEN  ARGON  NITROGEN  p.  7.577 13.40 21.32 2B.79 34.90 42.85 46.80 51.39 55.42 62.41 67.59 73.23 86.84 88.95 97.45 113.31 1Z7.37 13B.65 156.76 174.09 190.50 202.13 223.33 236.60 225.37 206.21 198.65 183.57 171.22 157.70 144.20 134.01 123.74 115.98 107.93 101.23 91.64 75.54 63.04 54.71 61.53 70.93 82.5 r 98.02 116.82 140.25 170.67 196.72 113.36 166.22 152.72 139.60  w 14.25 30.71 33.51 39.05 41.66 44.41 4B.33 53.33 58.58 63.63 69.69 79.57 86.84 101.73 118.50 136.71 150.64 187.59  225.26  246.49 228.86 195.65 160.22 139.46 130.99 123.62 117.36 110.54 104.79 99.30 84.15 81.02 75.57 70.72 67.02  p 0.0165 0.0352 0.0374 0.0788 0.0920 0.1279 0.1600 0.2374 0.3075 0.4300 0.4520 0.4947 0.5466 0.6256 0.6753 0.7155 0.7477 0.7967 0.8666 0.90B8 0.B6O6 0.B151 0.7530 0.7256 0.6557 0.5887 0.5598 0.5139 0.4442 • 0.4222 0.3756 0.3618  14.44 22.87 24.39 34.57 37.55 41.64 45.91 53.38 60.73 74.30 77.33 83.39 91.30 104.82 115.45 123.85 131.84 145.64 166.63 182.18 173.05 162.69 150.21 145.82 133.93 123.73 119.61 114.27 105.06 102.23 95.85 88.52  0.0070 0.0123 0.0376 0.0386 0.0877 0.09B9 0.2041 0.2449 0.2999 0.3584 0.4048 0.4702 0.5457 0.6112 0.7010 0.7596 0.8197 0.8696 0.9434 0.9814 0.9125 0.8867 0.0513 0.8235 0.7906 0.7248 0.6500 0.5689 0.4815 0.3995 0.3298 0.2863 0.2742 0.2459 0.1990 0.1614  8.S79 13.97 26.21 27.49 38.71 41.35 53.93 59.40 66.03 74.21 81.75 93.21  169.16  125.35 151.10 172.92 198.63 224.83 274.41 305.35 276.87 261.93 244.06 230.41 213.79 188.30 164.34 144.36 128.28 115.15 164.68 85.09 72.70 59.82 53.3S 49.28  -215ISOTHERMS ON PULP BEATEN I MINUTE—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION NITROGEN "~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 0.492T 0.4616 0.4361 0.3821 0.3149  ARGON  8.966 13.69 27.72 34.62 36.43 43.23 47.06 51.11 55.97 61.5) 67.22 74.19 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  125.74 118.74 111.63 104.29 99.17 93.5* 66.05 60.36 72.30 63.46 36.08 33.IT  0.5426 0.4865  0.4229 0.3849  G.34ed 0.3622  0.3547 0.3480 0.3259 0.2910 0.247V  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  p. 0.00046 0.00164 0.0158 0.0210 0.0484 0.0771 0.1377 0.1883 0.2491 0.3163 0.3909 0.4622 6.3261 0.3855 0.6406 0.7020 0.7543 0.6043 6.843* 0.8664 0.9173 0.9586 0.9154 0.8492 6.7783 0.6771 0.5884 0.5447" 0.4946 0.4719 6.4660 0.4269 0.3940 0.3394  W AI4SXR14 6.36V 11.12 24.34 26.23 32.00 35.92 41.04 45. 10 49.91 54.60 61.31 68.27 76.64 63.02 92.21 104.00 115.67 128.95 142.42 153.18 200.84 241.31 201.65 158.93 134.21 113.13 99.93 94.77 88.73 76.86 72.53 66.61 62.75 39.57  P 0.00420 -U.0137 0.03B6 0.0933 0.1167 0.1845 0.2437 0.2891 0.3442 0.3891 0.4451 0.4968 0.5369 0.5733 0.6190 0.6903 0.7496 0.7952 6.8456 0.9196 0.9822 0.9228 0.8672 0.8383 0.7731 0.7098 0.6519 0.6084 0.5479 0.4950 0.4391 0.4071 0.3697 0.3612 0.3544 0.3450 0.3222 0.2839 0.2389  P.  5.194 13.56 23.00 33.49 36.68 43.38 49.13 52.89 58.21 63.17 68.65 74.81 80.26 85.50 92.39 104.77 117.65 128.73 U2.il 163.00 192.14 174.61 159.73 152.38 lid.32  127.28 118.57 111.83 104.22 98.34 93.32 87.93 83.44 78.42 71.17 66.17 38.94 51.94 49.69  ISOTHERMS ON PULP BEATEN 5 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION p P* 0.00032 0.00285 0.0119 0.0140 0.0310 0.0668 0.1029 0.1519 0.2037 0.2625 0.3510 0.4292 0.4963 0.5692 0.6762 0.7566 0.8569 0.9177 6.9413 0.9028 0.8378 0.7286 0.6221 0.9333 6.4926 0.4669 .0.4389 0.4066 0.3724 0.2611  "odi. 6.493 19.38 23.49 25.03 29.B7 34.38 38.04 41.08 44.36 47.89 93.06 98.54 64.29 71.56 85.13 98.12 122.19 152.20 177.61 154.30 125.34 102.93 90.50 83.60 80.60 69.86 62.16 36.34 55.60 48.94  0.00400 0.0090 0.0236 0.048B 0.0898 0.1102 0.1456 0.1877 0.2451  32.64 35.23 38.70 42.38 46.78  0.3626 0.3639 0.4268 0.4774 0.5647  56.46 56.51 62.09 67.35 76.57  9.808 10.01 17.98  25.60  0.7023 0.7833 0.8670 . 0.9212 0.8730  95.20 108.53 124.33 137.65 129.92  0.7465 0.6804 • 0.5554 0.4719 0.3979  112.36 105.09 94.23 88.32 82.68  0.3493 0.33 86 0.3079 0.2716 0.2284  67.52 60.63 54.09 50.20 46.97  "S  0.0151 ,0.0561 0.1049 0.1408 0.1699 0.2333 0.2860 0.3560 0.4273 0.9133 0.5850 0.6481 6.7217 0.7784 0.B351 0.8949 0.9244 0.96T4 0.9136 0.8776 0.8373 0.7761 0.6920 0.5968 6.4967 0.4037 0.3255 0.2806 0.2689 0.2510 0.2123 0.1680  mlttSXIA* 12.94 28.20 36.01 40.79 44.63 51.26 57.45 65.01 74.71 88.43 103.45 119.64 139.12 159.64 184.07 221.21 250.51 310.59 27b.ii  240.62 207.94 178.42 152.44 130.73 113.31 99.52 88.54 78.53 68.11 58.56 51.11 45.65  -216-  ; ISOTHERMS ON P U L P K A T E N K> M I N U T E S — S O L V E N T EXCHANGE DRIED FROM WATER SUSPENSION ARGON  [NJTROGEN  : *i 0.2*40 0.1270 0.3951 0.4692 0.5449 1>.ftll2 0.67»2 0.7*8* 0.8025 0.6547 0.8975 " 0.9443 6.9845 0.9327 0,8339 0.7140 0.6649 0.6116 0.5624 0.5073 0.4714 0.4383 0.3961 0.3594 l  1  "oft.  i  41.54 50.81 54.92 ,,61.83 69.09 76.81 44.56 97.81 109.21 124.19 142.72 176.42 242.82 182.39 127.45 100.32 92.S3 06.46 81.38 75.63 64.78 59.52 55.96 53.11  1  '  . f  1 ! ! 1 |  t 1 i.  1 1  •  •  8.411 —^—izxtr 14.16  0.00117 0.00388 0,0084 0.0232 0.0307 0.0478 0.0715 0.0982 . 0.1533 0.1913 0.2329 0.2978 0.3431 0.4090 0.4757 0.3417 0.6352 0^7335 6.8099 0.8762 Q.9046 0.9585 0.9866 0.9481 0.8883 0.8239 0.6914 0.6098 0.5605 0.5173 0.4735 0.4487 0.4207 0.3923 0.3576  19.33 25.06 27.26 29.97 32.94 35.35 39.99 42.64 45.80 50.85 54.11 59.98 65.44 72.25 81.97 97.72 114.72 134.13 144.80 187.97 228.67 191.31 151.05 127.25 100.96 91.08 85.75 81.67 69.44 64.37 60.92 58.09 55.19  Pi  OXYGEN  W  0.0134 0.0298 0.0629 0.1104 0.1381 0.1856 0.2177 0.2476 0.2947 0.3310 0.3619 0.3917 0.4*57 0,5248 0.5861 6.6423 0.7145 0.7770 0,8506 0.9460 . 0.8731 0.8314 0.7737. 0.7285 6.6661 0.6087 0.5617 0.5051 0.4546 0.4180 0.3744 0.3607 0.3515 0.3398 0.3111 0.2700  ~!  1 j 1 | 1  j 1  10.99 18.11 25.89 , 33.01 1 36.15 40.19 43.27 45.91 • 1 49.36 ' 52.70 55.61 58.4* 65.65 72.23 [ 80,37 J •8.90 100.52 112.64 128.99 158.90 . 141.24 131.56 121.67 113.89 105.69 98.25 93.08 86.95 | 82.35 • 78.54 74.13 69.32 64.83 58.42 53.04 48.15  i  ISOTHERMS ON UNBEATEN P U L P S H E E T S — V A C U U M DRIED PRIOR TO S O L V E N T EXCHANGE DRYING I NITROGEN  i l  i  0.00233 -P. 0.0136 0.0390 0.0578 0.0971 0.1477 0.1903 0.2475 0.3090 0.4078 6.4868 0.5620 0.6422 0.7645 . 0.8451 0.9197 0.9699 0.8868 0.8243 0.7543 0.6B17 0.6110 0.560* 0.5169 0.4770 0.4447 0.4047 ' 0.3680  ARGON. P 6.367 0.670 0.672 0.974 1.084 1.246 1.339 1.489 1.646 1.890 2.100 2.312  2.524 2.768 2.973 3.247 3.804 3.177 3.613 2.932 2.828 2.804 2.730 2.686 2.413 2.083 1.897 1.809  , |  . .  0.0182 0.0380 0.0741 0.0968 . 0.1427 0.1972 0.2586 0.2967 0.3544 0.4285 0.4923 0.5520 0.6U5 0.7302 0.8162 0.8859 0.9453 0.9012 0.8421 0.7703 0.7095 0.6733 . 0.5992 0.5374 6.4742 0.4352 0.4154 0.3902 0.3*39 0.3551 0.3472 0.3361 0.3105 0.2655  0.421 0.654 0.879 1,000 1.176 1.352 1.531 1.681 1.859 2.085 2.322 2.520 2.731 3.100 3.333 3.515 3.664 3.576 3.476 3.380 3.299 3.263 3.150 3.073 2.477 2.885 2.663 2.787 2.6*6 2.446 2.22* 2.049 1.808 1.565  ISOTHERMS ON U N B E A T E N PULP S H E E T S WITH 5 . 3 % MOISTURE PRIOR T O S O L V E N T EXCHANGE DRYING ARGON  NITROGEN, • P '  P P. 0.00459 0.0181 0.0479 0.0710 0.1089 0.1651 0.2206 0.2789 0.3551 0.4019 0.4775 0.5501 0.62*9 0.6842 0.7731 0.8475 0.9086 0.9627 0.9899 0.9586 0.9022 0.6405 0.7648 0.6715 0.6656 0.5400 0.4952 0.4694 0.4372 0.4041 0.352* 0.2819  0.650 1.061 1.326 1.477 U623 1.830 2.020 2.231 2.508 2.678 2.998 3.270 3.566 3.733 4,070 4.2*3 4.505 5.040 6.422 5.158 4.740 4.546 4.429 4.310 4.204 4.107 3,774 3.356 2.894 2.677 2.470 2.216  0.0159 0.0277 0.0788 0.1004 0.1705 0.2302 0.3248 0.3926 0.4339 0.4833 0.5510 0.6101 0.6**1 0.753* 0.8677 0.9380 0.9850 0.9288 6.8*2* 0.7887 0.7181 0.6456 0.5827 0.5245 6.4827 0.4471 0.4108 0.3868 0.3613 0,3494 0.33*1 0.3207  OXYGEN  w  1  mltCSXfya. 0.534 0.861 1.408 1.576 1.920 2.202 2.620 2.951 3.178 3.450 3.810 4.124 4.445 ' 4,830 5.286 5.54* 5.74* 5.575 5.344 5.274 5.165 5.034 4.929 4.801 4.643 4.594 4.476 4,392 " 4.090 3.557 3.1** 2.645  ' I  1  P . cw ' 0.0314 0.0654 0.1237 0.1576 0.2388 0.2818 0.3231 0.3835 0.4517 0.5142 0.6024 0.6B69 0.7643 0.8422 0.8899 0.9473 0.8919 0.8127  o.tui 0.6683 0.5477 0.4652 0.3982 0.3538 6.3671 0.2866 0.2683 0.2621 0.2386 0.2107 6.1822  .  •W  '  0.577 . 0.847 1.140 1.313 1.611 1.806 1.969 2.222 2.531 2.802 3.151 3.436 3.A71 3.911 4.113 4.626 4.223 3.94B 3.7*83.659 3.470 3.343 3.229 3.124 2.44* 2.824 2.349 2.150 1.759 1.598 1.431  .  ISOTHERMS ON VACUUM DRIED UNBEATEN PULP SHEETS  ISOTHERM ON UNBEATEN PULP SHEETS WITH 14.4% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING NITROGEN P  V  0.00053 0.00280 0.0109 0.O3O3 0.0623 0.0938 0.1386 0.1760 0.2203 0.2691 0.3427 0.4104 0.4?62 0.5586 0.6364 0.7185 0.7733 0.9197 0.973? 0.986? 0.9713 0.9126 0.8328 0.7640 0.6730 0.5960 0.5422 0.5036 0.4769 0.4578 0.4)40 0.3930 0.3439 0.2909  <w  0.786 1.714 2.761 3.702 4.297 4.719 5.245 5.704 6.157 6.642 7.531 B.361 9.186 10.30 11.26 12.23 12.70 13.61 14.61 15.77 14.74 14.06 13.73 13.58 13.27 13.04 12.85 12.23 11.08 9.643 9.661 8.214 7.559 6.891  0.031 0.050 0.071 0.098 0.106 0.132 0.146 0.152 0.149 0.162 0.200 0.192 0.225 0.299 0.452 1.246 0.436 0.279 0.264 0.181 0.20T 0.181 0. 164 0.149 6.176 0.149 0.149  \  9_  w  aUBXeVt  0.0380 0.0882 0.1229 0.1587 0.2091 0.2675 0.3021 0.3672 0.4350 0.3143 0.5897 0.6791 0.7509 0.8193 0.8882 0.9624 0.8671 0.8137 0.7464 0.6702 0.5607 0.9056 0.4645 0.4274 0.3920 0.3537 0.3217 0.2828  0.022 0.052 0.093 0.005 0.116 0.136 6.147 0.179 0.196 0.209 0.224 0.255 6.282 0.298 0.336 0.401 0.331 0.306 6. 27* 0.246 . 0.210 0.206 0.165 0.173 6.168 0.153 0.140 0.133  ISOTHERMS ON VACUUM DRIED UNBEATEN PULP SHEETS ARGON  NITROGEN  2.629 5. 144 8.850 12.91 16.41 19.92 22.40 23.81 25.22 26.46 27.56 30.27 32.38 34.38 37.62 44.01 *9.3l 58.15 68.69 78.14 69.30 99.82 111.04 127.47 122.49 114.33 105.13 98.13 89.65 83.27 78.96 71.26 62.78 55.39 46.33 42.62 37.70  mUBtBUt  0.0119 0.0326 0.0721 0.1144 0.1746 0.2321 0.2970 0.3960 0.4806 0.5620 0.6383 0.TO88 0.V7B2 0.6575 0.9457 0.9693 0.9434 0.8550 0.7744 0.7052 0.6452 0.5366 0.4964 0.4389 6.4214 0.3812 0.3470  ISOTHERM ON UNBEATEN P U L P S H E E T S WITH 33JS>. MOISTURE PRIOR TO S O L V E N T E X C H A N G E DRYING  0.00017 0.00057 0.00200 0.006} 0.0132 .0.0294 0.0485 0.0667 0.0833 0.1002 0.1164 0.1610 0.1971 0.2313 0.2821 0.3752 0.4433 0.5397 0.6263 0.6972 0.7635 0.6208 0.8743 0.9699 0.9153 0.6356 0.7646 0.7119 0.6384 0.5753, 0.5312 0.4925 0.4802 0.4659 0.39T0 0.3474 0.27*1  ARGON  NITROGENt  p p* 0.0326 0.0994 0.1409 0.1659 0.2463 0.3031 0.3598 0.4225 0.4964 0.5577 0.6290 0.6962 6.7388 0.8310 0.8677 1.0000 0.9416 0.8572 6.7712 0.7026 0.6620 0.59J5 0.3396 0.4775 6.4)16 0.3929 0.3715 0.3263 0.2906  OXYGEN _p P 0.0353 0.0878 0.1332 0.2032 0.2316 0.2956 0.3462 0.4248 0.5138 0.5733 0.6472 0.7089 6.779* 0.8460 0.9078 0.9566 0.90T8 0.8423 0.7634 0.6956 0.6599 0.5641 0.4794 0.4344 6.3444 0.3727 0.3276 0.2761 B  0.025 0.059 0.091 0.103 0.121 0.138 0.143 0.168 0.166 0.190 0.213 0.231 6.243 0.269 0.289 0.472 0.331 0.277 6.556 0.223 0.203 0.164 0.166 0.139 6.136 0.126 0.129 0.113 0.102  0.018 0.061 0.092 0.115 0.123 0.145 0.161 0.164 0.215 0.239 0.256 0.279 0.287 0.357 0.455 0.628 0.453 0.363 6.244 0.263 0.245 0.211 0.160 0.195 6.144 0.147 0.132 0.114  -218-  APPENDIX B SURFACE AREA OF HANDSHEETS (DYNAMIC ADSORPTION APPARATUS)  BEATEN I MINUTE  UNBEATEN PULP SHEETS  t  *  *adt.  0.053430 0.053430 0.053430 0.053360 0.053360 0.053360 0.053360 0.053360 0.151600 0.152560 0.152360 0.151980 0.237700 0.237700 0.237410 0.237410 0.236810 0.236810 0.236810  0.067 0.066 0.068 0.063 0.066 0.067 0.066 0.067 0.111 0.106 0.112 0.101 0.124 0.136 0.130 0.123 0.124 0.136 0.131  0.189790 0.186770 0.187520 0.185670 0.1B7890 0.1B530O 0.120080 0.119730 0.119640 0.119610 0.118900 0.118190 0.043440 0.043080 0.042300 0.042340 0.042760 0.041630 0.041380  0.847509 0.853592 0.833600 0.690768 0.852410 0.640348 0.652410 0.846336 1.613393 1.700981 1.609343 1.767324 2.507694 2.299938 2.402802 2.522943 2.495391 2.288655 2.377427  0.053490 0.053490 0.053490 0.152170 0.152170 0.131980 0.151980 0.151960 0.151980 0.236610 0.236510 0.236810 0.236220 0.236810 0.236220  0.049 0.045 0.050 0.047 0-049 0.046 0.043 0.046 0.066 0.081 0.066 0.081 0.085 0.078 0.117 0.104 0.122 0.112 0.111 0.099  1.146685 1.250279 1.135677 1.209163 1.156742 1.231485 1.329677 1.231485 2.033788 2.222233 2.030793 2.218962 2.115412 2.295200 2.654011 2.972732 2.552290 2.762107 2.795828 3.120160  BEATEN 10 MINUTES 0.180340 0.185300 0.182080 0.185670 ft-IROAAn '0.184400 0.179650 0.118660 0.115580 0.117620 0.116590 0.116540 0.116930 0.116080 0.112340 0.044460 0.043580 0.043490 0.Q43080 0.043080 0.042760 0.043000 0.042300  0.066 0.063 0.064 0.069 0.066 0.064 0.068 0.056 0.047 0.047 . 0.044 0.048 0.053 0.045 0.057 0.028 0.032 0.028 0.030 0.027 0.037 0.027 -0.031  3.316299 3.592431 3.476602 3.291343 3.331671 3.522431 3.220992 2.392589 2.758129 2.859826 3.007200 2.775058 2.479914 2.964009 2.212656 1.686039 1.427803 1.6475B1 1.497496 1.659157 1.214612 1.637331 1.411285  0.106 0.120 0.109 0.113 0.108 0.111 0.107 0.091 0.097 0.091 0.091 0.108 0.056 0.057 0.058 0.052 0.054 0.054 0.052  2.199994 1.912154 2.108198 2.010244 2.141B3? 2.048686 1.279601 1.496749 1.409236 1.495044 1.475229 1.245746 0.817467 0.789671 0.757451 0.851009 0.816975 0.808115 0.826767  BEATEN 3 MINUTES  BEATEN J MINUTES 0.053630 0.053630 0.053430 0.053490  P  >  0.053600 0.053600 0.053600 0.053530 0.053530 0.053450 0.053450 0.053450 0.152320 0.152320 0.152080 0.152080 0.151980 0.151980 0.236910 .0.236910 0.236550 0.236400 0.236520 0.236450  0.043 0.044 0.041 0.042 0.04* 0.043 0.042 0.042 0.071 0.071 0.074 0.074 0.075 0.074 0.102 0.097 0.106 0.098 0.098 0.099  1.322493 1.292776 1.365663 1.339922 1 .316R86 1.303601 1.353592 1.341718 2.513229 2.535046 2.421052 2.429124 2.379646 2.435357 3.046921 3.201587 2.924307 3.172429 3.162575 3.137699  APPENDIX C T a b l e 1: ' N i t r o g e n A d s o r p t i o n Isotherm Data o f Hunt, B l a i n e and Rowen (18) A: A l k a l i S w o l l e n S o l v e n t Exchange Dried 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  B: Sample A w i t h 3.3% Water Rej^ a i n Volume* P/P 0  0. 079 0.126 0.190 0.245 0.302 0. 419 0. 616 0.718 0.716 0.826 0.959  6.4 7.1 8.1 8.9 9.8 12.0 18.1 23.0 23.1 28.5 34.0  Desorption 0.842 0.665 0.531 0.478 0. 340  * **  31.2 27.6 25-0 17.6 10.5  Sample A w i t h 11.0% Water Regain Volume* p/p o  0.107 0.146 0.191 0.261 0.355 0.463 0.562 0.678 0.832 0.923  0.48 0.53 0.54 0.62 0.64 0.72 0.79 0.97 1.90 3.83  Desorption 0.819 0.813 0.667 0.555 0.469 0.413 0. 304 0.163  2.59 2.54 1.38 O.96 0.74 0.68 0.65 0.57  D: C o n t r o l , Water Swollen, Solvent Exchange D r i e d Volume* P/P 0  0.055 0.084 0.159 0.207 0.256 0.333 0.525 0.654 0.806 0.786 0.872 0.958  Desorption 0.862 0.613 0.515 0.475 0.455 0.291  Expressed as mis.(S.T .P.)/g. Adsorbed Not p l o t t e d on F i g u r e 5  8.8 9-7 11.5 12.5 13.6 15.4 20.0 22.8 25.4 25.8 27.1 30.0  27.6 25.1 24.3 22.4 20.3 15.1  E: Outgased** Cellulose Fibres P/P  Q  0. 081 0.152 0.194 0.249 0.283 0.360 0.516 0.692 ,0.813 0.928  Volume* 0.14 0.15 0.17 0.19 0.19 0.19 0.17 0.25 0.41 . 0.66  Desorption 0.813 0.709 0.515 0.327 0.266  0.38 0.30 0.21 , 0.18 0.17  -220-  APPENDIX C  s  Table 2:. I s o t h e r m Data o f H a s e l t o n (13) N i t r o g e n a d s o r p t i o n on b e n z e n e - d r i e d specimens , _ Holocellulose r h l o r  Sprucewood  f  KOH-Extracted „ ?^" Holocellulose C  h  l  e  1  Volume Adsorbed*  p/p  0. 014 0.037 0.075 0.126 0.192 0.260  0. 56 0. 71 0.84 0.96 1.07 1.20  0.001 0. 027 0.083 0.140 0.204 0.273  4.64 10.2 13.0 14 .9 16.7 18.6  0.007 0.028 0.078 0.135 0.199 0.270  8.06 11. 0 13.6 15.5 17.3 19.2.  0.328 0.395 0.466 0.540 0.608 0.679  1.31 1. 41 1. 54 1.73 1.93 2.12  0.. 340 0.410 0.484 0.551 • 0.616 0.683  20.6 22.9 25.7 28.5 31.3 34.1  0.339 0.409 0.482 0.551 0.615 0.678  21.2' 23.5. 26.3 29.2 32.4 35-9  0.750 0.817 0.882 0.944 0.966  2.36 2.64 3.11 3.93 4.56  0.751 0. 815 0. 871 0.919 0.961  36.8 39.4 41.6 43.6 45.3 46.9  0.739 0. 801 0.863 0.924 0.950  39-7 43.8 47.5 49.8 50.6 51.7  p/p  0  o  V  s  Desorption  Volume Adsorbed*  .  a t -195.6 °C.  P/P  Q  V  s  Volume Adsorbed*  0.921 0.853 0.759 0. 665 0.568 0.475  3.79 3.20: 2.71 2.45 2.09 1.78  0.910 0.825 0. 746 0.665 0.573 0.484  43.9 41.5 39.1 36.8 34.4 32.0  0.892 0.815 0.737 0.662 0.578 0.488  49.6 48.3 45.8 41.9 37.4 34.4  0.372 0.275  1.36 1.22  0.438 0.428 0.329 0.230 0.137  28.8 24.6 20.8 17.9 15.2  0.457 0.375 0.275 0.181  27.8 22.9 20. 0 17.2  *  E x p r e s s e d as m i s . ( S . T . P . ) / g .  -221-  APPENDIX C Table 3:  I s o t h e r m Data o f Merchant (12)  A d s o r p t i o n o f N i t r o g e n on WAN-Dried F i b r e s * Sample. E-37 WAN-Dried from n-Pentane P/P,  Volume Adsorbed, ml.(S.T.P.)/g.  .005 .061 .122 .188 .285 .403 • 521 .630 .751 .861 .924 . .957  14.83 26.89 31.45 35.71 41.34 49.33 58.73 69-83 86.11 108.05 131.45 154.34  .870 • 715 .596 • 513 .444 .342 .225  • 117.97 90.36 79-14 72.92 53-91 45.51 38.26  :050 .289 • 553 • 759 .833 .912 • 956 • 974  25.75 41.64 61.57 87.63 100.93 126.02 151.39 175.61  901 804 713 558 487 474 449 408 267  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,  . 015 .053 .203 .476 .607 • 776 ' .887 • 947 • 972  14.93 19.70 27. 49 41.13 49.80 64.58 81.22 101.29 121.61  .943 .885 • 793 .656 .551 .503 .484 .478 .468 .437 .384 .245  105.73 86.04 71.60 60.08 54.68 52.48 50.63 47.87 44.45 39.83 36.22 29.48  .114 .188 .255 .302  23.51 26.95 29.87 32.06  * WAN-Dried F i b r e s means f i b r e s d r i e d by s o l v e n t  exchange.  (WAN = W a t e r - A l c o h o l - N o n p o l a r solvent)  -222-  APPENDIX C Table 3 C o n t i n u e d : Sample E-3 WAN-Dried from Benzene P/P,  Volume Adsorbed ml.(S.T.P.)/g.  090  9.92  163  264  Sample E-96, W a t e r - D r i e d over P ^ J - J Water-Soaked 1 4 Days, WAN-Dried from n-Pentane Volume P/P o Adsorbed ml.(S.T.P.)/g. . 0 0 6  6.50  11.49 13.26  .050  1 0 . 7 5  .121  1 3 . 0 5  320  14  .69  .228  15.83  434  17.21  .283  17.26  560  2 0 . 5 2  712  .431  2 1 . 3 9  2 5 . 7 5  .577  882  35-36  .703  26. 71 32. 44  .996  42.65 54.06 66.64  3 0 . 9 1  .964  5 7 . 9 0  2 7 . 5 3  .848  45.86  958  .  47.97  9 8 1  6 1 . 9 5  911 766  4 1 . 5 1  666 601 528  25.89  24.33 22.61  487 462  19.31  416  17.09  305 203  14.53'. 12.48  025  7.25  313  1 4 . 3 9  605  21. 72  .874 • 970  .662 • 532  36.86  .468  32.31 25.10  .343  18.86  .022  9:01  .588  26.94  . 7 6 1  35.00  • 9 3 8  48.19  .988  59.81  .960  55.00  811 929 972  41.25  .918  5 3 . 8 3  .840  49.83 44.39  985  6 7 . 7 1  .754  4 0 . 2 3  .649 .547  36.07 32.62  31.58  30.08  38.68  885 722  29-24  .517  565  25.07  .496  30.09  09  .483  27.46  491  23.  473  2 0 . 5 0  .457  2 3 . 5 7  455  18.62  .434  15.06  22.03  '334  .406  2 0 . 8 6  202  1 2 . 4 1  -223Table  4:  Isotherm Data o f Sommers (5)  n-Pentane D r i e d  C0_ Removed Above C r i t i c a l Poin (Cotton D r i e d )  P/P,  Volume Adsorbed*  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  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  0.1182 0.1410 0.1619 0.1738 0.1815 0.1914 0.2412 0.2768  6.49 6.68 6.83 6.91 6.97 7-03 7-37 7.65  0.9293 0.7966 0.6233 0.5076 0.4644 0.4003 0.3149  34.70 27-97 24.48 23-12 21.38 17.73 15.72  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  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  0.1206 0.1547 0.1911 0.2134 0.2297 0.2522 0.6746 0.9370 0.9862  11. 05 11.77 12.51 13.03 13.36 13.82 22.94 32.94 40.28  0.8743 0.7019 0.6450 0.5594 0.4347 0.3956 0.3106  30.88 25.27 24.44 23-36 18.76 17.25 15.34  0.9449 0.8753 0.6599 0.5964 0.5557 0.4939 0.4566 0.4166 0.3640 0.3061  Volume Adsorbed*  31.11 18.83 13.17 12.68 12.46 12.02 10.82 9.28 8.53 8.00  COp Removed Above C r i t i c a l Point P/P,  Volume Adsorbed*  0.1008 0.1203 0.1479 0.1631 0.2148 0.2553 0.2923  9.67 9.95 10.41 10.63 11.43 11.99 12.51  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  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  0.9673 0.9490 0.9284 0.9060 0.8470 0.7482 0.6305 0.5401 0.4727 0.4488 0.4084 0.3445  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.  1  -224APPENDIX C Table 5:  I s o t h e r m Data on Hollow F i l a m e n t Rayon S u p p l i e d by S c a l l a n (172)  Nitrogen Adsorption Smoothed V a l u e s * *  P/P, 0.185 0. 300 0.405 0. 430 0. 460 0.480 0. 500 0.595 0.660 0. 740 0. 790 0. 850 0. 895 0.950 0.965  Experimental Values D r i e d a t 105°C then S o l v e n t Exchange S o l v e n t Exchange Dried Dried  Volume Adsorbed*  P/P,  Volume Adsorbed*  4.6 5.5 6.4 6.6 6.9 7.1 7.3 8.3 9.1 10. 4 11.5 13.1  0.20  4.77 6.15 7.76 11.38 20.02 .  14.9 18.8 20.6  0.40  0.59-5 0.815 0.97  Desorption 0.97 0.74 0.50 0.455  20.77  14.77 8.97 7.13  0.41  6.46  0.295 0.195  5.55 4.77  p/p 0.18 0.395 0.60 0.80 0.965  Volume Adsorbed* 4.58 6.35 9.27 11.61 21.18  Desorption 0.965 0.745 0.50 0.45  0.40  18.61 13.94 10.03 7.11 6.35  Desorption 20.6 0.965 0.950 19.7 0.895 17.7 0.850 16.5 0.790 15.2 0. 740 14. 3 0. 660 12.9 11.8 0.595 0.500 9.5 0.480 8.5 0. 460 . 7.5 0.430 6.6 6.4 0.405 0.300 5.5 4.6 0.185  * **  Volume adsorbed  e x p r e s s e d as mis.(S.T.P. )/g.  These v a l u e s were p i c k e d o f o f f a smoothed i s o t h e r m curve and used i n a l l c a l c u l a t i o n s .  -225APPENDIX C ?able  6:  Accessibility  Molecular D i a m e t e r , ft  D a t a o f S t o n e and  Molecular,. wt. x 10 ^  560  2000  270  Scallan  (69, 172)  I n a c c e s s i b l e Volume, ml. K r a f t Pulp, Percent Y i e l d 65. 1 %  44.6  %  41.6  -  1. 40  1.41  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  Raffinose  0. 31  0.14  0. 07  Glucose  0. 15  0.03  0. 07  12 8  -226-  APPENDiX D  TABLE |: PORE ANALYSIS USING STANDARDIZED NITROGEN ISOTHERMS  PARALLEL SIDED FISSURE MODEL  CYLINDRICAL PORE MODEL  UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION wall separation 0.900 0.850 0.800 0 . 750 0.700 0.650 C.600 _ 0.550 0.500 0.480 0.460 0.440 0.400 . 0.350  109.4Q0  ini;ooo  164.100 149.?00 138.400 128.700 ]120.BOO 1 4 . 100 10S.500 90.200 flI.4 00 76.900 71.500 66.000  96.4B3 60.781 55.128 45.72 1 39.097 34.135 10.248 77.094 25.164 . 24.1B4 23.263 21.993 20.248  pore Vj-rryg. 7.51 J 9.230 9.981 8 . 294 B.477 7.551 6.916 10.32 7 22.269 12.686 6.050 6. 54? 6. 503  turn of pore area *»rryg. 7.513 16.743 26.724 35.Q1B 43.495 51 . 0 4 5 57.9b2 68.288 90.558 103.244 109.294 115.636 1'2'2.33B'  pore .volume 23.383 20.777 17.750 12.233 10.691 8.314 —6.?48 9.025 18.077 9 . B97 4.540 4.641 4.247  s u m of  port vol  ad •.  A  A port volume  ml(5T.FH  APOre  23.383 6.663000 44.159 I . I45679 61.909 1.58BB32 74.142 1.600437 84.833 1.907590 93.147 1.925174 99.895 1 . 9 5 2 5 6 T 108.921 3.165624 126.997 17.892715 136.895 10.433136 141.435 5.079371 146.075 2.818710 156.323 3.304694"  diam of  turn of pore area  pore ' volume mlSTfJ'g  sum of pore vol A pore volume ml(S.T^.A(«« • »  14.373 12.70B 13.864 12.97B 12.436 20.521 49.190 27.653 12. 132 l l . 163 9.915  9.206 21.518 35^891' 48.599 62.463 75.441 87.877 108.398 157.588 185.241 197.373 266.536 218.451  25.492 24.030 21.687 15.599 14.298 11.497 9.612 13.998 30.840 16.568 6.953 5.498 4 . 844  25.492 0.758829 49.522 1.408004 71.209 2.085208 86.808 2.214420 101.106 2.795108 112.663 2.943976 122.215 3.103B94 136.213 5.530292 167.053 34.608826 183.621 19.874390 190.373 8.884956 196.571 4.184652 201.415 3.045551  12.108 9.B02 Hi.ftns 10.435 9.547 9.547 11.467 19.622 41.762 32.673 10.693 10.607 9.058  12.108 21.910 37.715 43.150 52.697 62.244 73.711 93.333 .135.(195— 167.768 178.460 189.067 198.125  33.527 19.131 12.809 9.846 8.457 8 . 863 13.385 __26.1B3— 19.575 6.128 5.699 4.425  14.510 28.123 40.677 5?-713 64.2BB 75.260 85.918 98.604 114.6*7 _133. 377_ 164.493 178.164 183.062  40.178 26.572 18.941 14-774 11.93 8 9.720 8.238 8.654 10.058 33 7Q* 6.370 7.346 2.393  .pore  A 0.900  0.850 0.800  0.750 0.700 0.650 0.600 0.550 0.500 0 . 480  0.460 0.440 0.400  0.350  19O.400  1B1.000 164. 100 149.200  138.400  128.700 120.BOO 114.100 105.500 90.700  81.400 76.900 71.500 66.000  _ .. 85.836  9.206  60.507 46.774 38.052  12.312  31 . 9 7 2  27.462 23.961 71 . 1 4 7 19.435  18.573 17.765 16.657 15.145  PULP BEATEN I MINUTE —SOLVENT EXCHANGE ORlEO FROM WATER SUSPENSION 0.900 0.850 o.aoo0.750 0.700 0.650 0.600 0.550 0.5000.480 0.460 0.440 0.400 0.350  184.500 160.300 146.500 135.000 126.000 119.000 113.000 107.000  —as.ooo 86.000 76 . 0 0 0 72.000 67.000 62.000  55.128 45.721 39.097 34.135 30.248 . 27.096 25.164 2 4 . 184 23.263 21.993 20.248  7.542 6.824 5.909 5.592 6.273 -Jj-.2i.3_ 18.'  24.SOB 31.631 37.540 43.132 49.405 5 9 . 149.. 78.057 92.776 9 8 . 142 104.27* 110.218  13.413 10.064 7.452 6.158 6 . 121 B. 516— 15.348 11.483 4.026 4.351 3.882  60,788 1 .200617 70 . B 32 1.316756 78.304 I .329630 B4.462 1.425853 90.583 1 .771008 QQ.nwi 7.9H4ft*5 114.447 15.191949 125.930 12.10*979 129.9^6 4.504688 134.3U7 2.642390 138.189 2 . 106696  0.900 0.850 0.800 0 . 750 0.700 0.650 0.600 0.550 0.500 0.460 0.440 0.400 0.350  184.500 160.300 146.500  85.838 60.507  126.000 119.000 113.000 107.000 99.000 86.000 76.000 72.000 67.000 62.000  36.052 31.972 27.462 23.961 21.147 19.635 18.573 17.765 16.657 1 5 . 145  33.527 52.65 9 81.771 91.617 100.074 108.937 122.32 2 168.080 174.208 179.907 184.332  0.998026 1.120967 I .4*.7*7* 1 .816402 1.924802 2.165S70 2.862077 5.287996 2.9. 3 B2 401 23.4B2407 7.83077* 3.976027 2.782394  PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0.900 o.asc141.000 0.600 127.500 0.750 117.000 0.700 108.500 0.650 101.500 0.600 . 0 . 5 5 0 - —95.500 89 . 5 0 0 0.500 ' 84.000 0.480 72.500 0.460 68.500 0.440 63.000 0.400 0.350- -59.000  . 96.483 69.781 5 5 . 128 45.721 39.097 34.135 -30.268 27.094 2 5 . 164 24.184 23.263 21.993 _20.248  11.841 10.238 8.787 7.895 7 . 163 6.457 —5..att8— 6.659 7.513 17.137 5.403 7.06 3 4.16S-  -1-1 . 8 4 1 22.079 30.866 38.761 45.924 52.3B1 SB.369 65.028 72.541 89.678 95.081 102.145 -III  —36.1 _36..aa323.047 59.900 15.626 75.526 11.643 87.169 9.034 96.203 7 . 110 103.314 5-^a43_ .109.15ft 114.977 5.820 6.098 121.075 "13.369 134.444 4.055 138.499 5.011 1*3.510 3. 7?l> |**, J3l1 T  .11**9**. 1 .27086* 1.398714 1 .523370 1.611956 1 .6*6356 1 ,f.Ollt.*q 2.041386 6.03606* 14.093420 4.536509 3.043396 1 *7rSlft9  0.900 0.850 0.800 0.750 r.,7nn 0.650 0.600 0.550 0.500 0.480 O.460 0.440 0.400 0.350  T  189.000 160.000 141.000 127.500 I 17.OOP 108.500 101.500 95.500 89.500 84.000 7? *on 68.500 63.000 59.000  85.838 60.507 46.774 3B.OS7 31.972 27.462 23.961 2 1 . 147 19.435  r  :  17.765 16.657 15.145  14.510 13.613 12.553 11.57 5 10.972 10.658 12.686 16.043 3H.73Q 11.116 13.671 4.898  T  40.17 8 1.195980 66.749 1.556900 85.6*90 1.621162 100-464 2.0973*9 112.402 2.333648 122.121 2.466925 130.359 2.660127 139.013 3.41B760 1 4 9 . 0 7 1 11 . 2 8 7 4 6 9 - 1 7 2 . 2 75. 178.646 140728 185.991 5.124681 188.384 1 .5044B6  PULP BEATEN 5 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0.900_ 0.850 0.800 0.750 0.700 0.650  1 -13.01-111 130.000 116.000 106.000 99.000 93.000 un.*nn  0.550 0.500 0.480 0.460 0.440 0.400— 0.350  84.500 81.000 78.000 67.000 63.000 ST..511053.500  96.483 69.781 55.128 45.721 39.097 34.13* 30.248 27.094 2 5 . 164 24.184 23.263 -2-U 20.248  5 . 166 5.017 *-"73 3.910 3.658 3.980 16.639 5.696 7 ->>** 4.890  9.39 1 16,908 23.396 28.562 33.579 41.511 45.169 49.14B 65.787 71.483 79- n i l 84.018  29.228 16.921 11.538 7.618 6.327 *-*3ij 3.815 3 . 197 3 . 2 30 12.981 4.274 3 . 194  29.22 8 *6.l*9 57.607 65.306 71 . 6 3 3  0.828750 0.933056 1 .032817 0.996761 1 .128978  79.877 1 .103710 83.07* 1 .121226 86.305 3.197532 99.2B5 13.683580 103.559 4.78190* ,HlH.9rt3 3 . 7 9 * 0 9(1 112.177 1.733299  0,900 0.B50 0.800 0.750 0.700 0.600 0.550 0.500 0 . 4 80 0.460 .Q...440—  153.000 130.000 116.000 106.000 99.000  85.838 60.507 46.77* 38.052 93.000 —31.9.72. 88.500 27.462 84.500 23.961 81.000 2 1 . 147 78.000 19.435 67.000 18.573 63.000— -17.765  11.508 9.986 9.263 7.824 • 093 6.738 6.904 6.72* B.3B6 38.019 12.281  11.508 21.494 30.75 7 38.580 _46.6.7-3_ 53.411 60.315 67.039 75.426 113.445 125..-73S  31.865 31 . 8 6 5 0 . 9 4 8 5 3 7 1.9.492 51.357 1.142076 13.976 65.332 1.343782 9.603 74.936 1.363295 8 - 3* t\ H3.7H7 1.6316. I A 5.969 89.251 1.528489 5.336 94.587 1.723177 4.587 99 . 1 74 1.812132 5.25B 104.432 5.900383 22.778 127.210 27.324524 7.063 . -134.256 9 . 0 0 0 B O 6,  PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0.900 0.850 0.800 0.750 0.700 £U.63Q„ 0.600 0.550 .0.500 0.480 0.460  159.000 136.000 122.000 111.000 102.000 9*,»nrt 90.000 85.500 80.500 76.000 66 . 0 0 0 >-3 . nnfi  96.483 69.781 55.128 45.721 * q -flQ7 3 4 . 135 30.248 27.094 25.164 2 4 . 184 _23.263.  .391 .517 .200 5.644 *.422 5.631  9.391 16.908 2*.108 30.956 3*..HQ* 41.538 45.960 5 1 . 591 57.757 72.724 7*-7in  29.228 16.921 12.804 10.100 6.215 4.31* 4.921  5.005  11.676 2,99 1  29.228 0.B2875O 46.149 0.933056 5B.953 1 .146091 69.053 1.321426 75.7H1 • 1 . 1 1 1 ? 9 5 81 . 4 9 6 1.439112 85.810 I .248314 90.732 1.726151 95.73 7 4 .954384 107.413 1 2.308504 -LlO^AU-4- 3.3**,?41  0.900 0.850 0.800 0.750 0.700 0.650 0.550 0.500 0.480 0.460 0.4*0 0.350  159.000 136.000 122.000 1 11.000 102.000 96.000 m nnn 85.500 80.500 76.000 66.000 ' 63.000 -59.00055.000 T  85.838 60.507 46.774 38.052 31.972 37 * A 7 23.961 21.147 19.435 I B . 573 17.765  11.508 9.986 10.306 10.4B6 ?.BB3 —9-*.q* 7.781 10.834 13.187 33.906 6.027  15.145  7.996  T  11.508 21.494 31.800 42.286 50.169 59.A/.* 67.6*5 78.479 91.663 125.572 133.599 i * 3 - W 150.658  31.865 19.492 15.550 12.871 8 . 130 6.01* 7.390 8.267 20.314 4.600 .670 3.907  31.865 0.946537 51.357 1.142076 66.907 1.495132. 79.77 7 1.827189 87.907 1.5B92B7 9ft,497 j . i 00*09! 102.510 1.942039' 109.901 2.919578 118.168 9 . 2 77696 13B.482 24.3689731 143.082 5.B7B546 1*7-9*? 3.3Q7797 151.859 2.456254 1  -227-  TABLE I. CONTINUED CYLINDRICAL PORE MODEL  PARALLEL SIDED FISSURE MODEL ' U N B E A T E N P U L P S H E E T S — V A C U U M DRIED PRIOR TO S O L V E N T EXCHANGE DRYING  .;»•  ' Mparatton,  *  a. ago  o-mo •0.b50 o.boo J1.2U 10.700 10.630  3.0bo 2.980U.SOJL 2.850 2.bis  g;Sgg *'° . S.YJ6 7  0.900 10*480-. 0.440 0.440 0.400 •oTTSo -  2.620 ,.i*.46j>_ 2.210 2.060 1.980 1.759  vdurm'  A  96.489 69.781 _55.J28 45.72i 39.09T 34.135 30.248 27.094 _2A..1M . 24.184 23.263 21.993 20.248  . mLSTfyg 0.6*7 0.054 _0^_053 0.037 0.028 0.032  0.057 Q.Ul 0.164 0.201 0.229 0.261  0.149 ..0.236 0.3B3 0.231 0.104 87571  0.462 0.698 1.081 1.312 1.416  0.055  0.517  1.787  0.178 0.122 0.094 0.055 0.035 0.036 0.054 0.127 0.192 0.299 0.173 0.074 0.242  sum of pore v o l 0.178 0.300 0.394 0.448 0.484 0.519  0.573 0.700 0.891 1.190 1.363 1.438 1.680  Aj*>" £POTt  0.005045 0.006715 . 0.008404 0.007140 0.006331 0.008235 0.015611 0.044449 0.189583 0.315194 0.193557 0.045027 0.131402 1  G.900 0.850 0.800 0 . 750 0.700 0.650 0.600 0.550 0.500 0.4SC 0.460 0.440 0.400 0.350  turn of : par* a m  diarn. of port A  U2t " 3.220 3.080 2.980 2.900 2.650 2.815 2.780 2.750 2.620 2.460 2.210 2.060 1.980  85.838 60.507 46.774 38.052 31.97 2 27.462 23.961 21.147 19.435 16.573 17.765 16.657  1.755  ;  voJumt  sum of pore vol  A P O " volumt  .'im&TJH-* " ** p  tM  !  0.070 0.142 0.21R 0.274 0.318 OTTTI 0.478 0.783 1.307 2.183 2.T05 2.884 3.782  0.194 0 . 141 0 . 114 0.069 0.046 0.049 0.081 0.208 0.329 0.525 0.299  15.145  0.070 0.072 0.076 0.056 0.044 0.055 0.105 0.305 0.524 0.876 0.522 0.179 0.898  85.838 60.507 46.774 38.052 31.972 27.462 23.961 21.147 19.435 18.573 17.765 16.657 15.145  0.080 0.070 0.062 0.075 0.090 0.134 0.168 0.804 1.050 1.023 1.067 0.867 C.569  0.080 0.150 0.212 0.287 0.377  6.511  0.67S 1.482 2.532 3.556 4.623-  0.222 0.136 0.093 0.043 0.093 6.114 0.130 0.548 0.659 0.613 0.612  85.838 60.507 46.774 38.052 31.972 27.462 23.961 21.147 19.435 18.573 17.765 •  0 . 110 0.100 0 . 124 0 . 186 Q.228 0.272 0.371' 2.052 2.736 5.849 1.412  0.110 0.210 0.334 .920 .747 1.020 1.391 3.443 6 . 179 12.027 13.939 16.476 18.713  0.305 0.195 0.187 0.228 0.235 6.241 0.287 1.400 1.715 3.504 1.096 1.354 1.046  2.552 6.886 13.188 21.300 30.029 39.437 49.254 68.659 103.596 122.561 142.007 152.2d8 158.421  7.066 8.460 9.509 9.957 9.003 8.334 7.588 13.237 21.405 11.362 11.143 5.524 2.997  0.194 0.334 0.449 0.517 0.563 0.612 0.693 0.901 1.230 1.754 2.053 2.150 2.589  0.005774 0.008234 0.010986 0.009756 0.008961 0.0124A8 0.026107 0.082278 0.368702 0.629321. 0.3B2142  U N B E A T E N PULP S H E E T S WITH 8 : 3 % MOISTURE PRIOR T O S O L V E N T EXCHANGE DRYING 0.900 ;0.850 0.800 !ftt.7W„ 0.700 0.650 0.600  6.550 0.900  ,0*486— 0.460 0.440 0.400  0.353  96.483 69.781 * - « A . . ,A?i.l2_8_„ 45.721 4.341 39.097 4.279 34.135 4.205 4.12V • 3 6 . 2 4 4 3.850 . -3.530 3.230 24.184 2.930 23.263 2.669 21.993 4.472  26.248  0.049 0.055 0.075  6.665 0.118 0.161 0.210 0.265 0.340  0.459 0.466 0.399  " 0.809 1.278. 1.733 ' 2 . 199 2.998  6.665 0.053  O.OAfl  6.247  0.424  2.895  0.263 0.118 0.077 0 . 072 0.069 0.083 0.086 0.329 0.384 0.355 0.350 0.283 0.144  6.263  0.322 _0.399 0.471 0.540 0.623. 0.704 1.038 1.422 "1.777 2.127 2.410 2.604  6.665765, 0.006533 0.006892 0.009465 0.012293 0.0191B1 0.024442 0.115375 0.380324 0.373612 0.391525 0 . 171941 6.105110  0.900 0.B50 0.800 0.750 0.700 0.650 0.600 0.550 0.500 0.480 0.460 0.440.,  4.730 4.570 4.472 4,405 4.341 4.279 4.205 4 . 127 3.A50 3.530 3.230 2.930,  0.755 0.885 1.433 2.091 2.705 3.316  0.006599 0.007998 O.0OB956 0.013132 0.018139 6.636361 0.041835 0.216569 0.739030 0.735510 0.781730  j U N B E A T E N P U L P S H E E T S WITH 14.4% MOISTURE PRIOR T O S O L V E N T EXCHANGE DRYING 0.900 .0.850 13.630 0.800 • J > . 7 9 Q _ - J 3 . 5.0.0. 0.700 13.350 0.650 13.200 0.600 13.050 6.556 U.flftti 0.500 12.180 .fl.4B.0„ _ l l » M f l 0.460 9.700 0.440 9.120 8.340 —7.626  96.463 69.781 _5?..128_... 45.721 39.097 34.133  36.248  27.094 25.164 24.184 23.263 21.993  26.246  6.646  0.075 0.086 6.119 0.137 0.153  6.145  0.998 _i«231 2.549 0.674 _ 1_. 1 7 5 T  .086  6.040  0.165 0.292_ 0.371 0.508 0.661  0.856  1.614 3.049. 5.594 6.466 7.642  6.731  0.260 0.170 0.154 0.176 ' 0.172 0.169 0.140 0.837 0.999 1.988 0.656 0.833 0.711  0.260 0.449 0.603 0.779 0.99t 1.120 1.310 2.148 3.147 5.135 5.791 6.625 7.335  0.007927 0.009351 0.013749 0.023027 0.030759 0.039118 0.055060 0.293676 0.989143 2.095921 0.733902 0.506147 0.3S5730  , UNBEATEN P U L P S H E E T S WITH 3 3 j S % MOISTURE PRIOR T O S O L V E N T E X C H A N G E  P.  0.850 0 . 600 0.750 0.700 0.650 0.600  6.536  0.500 0.480 .0.460 ,0.440 '0.400  6.556_  120.800 96.483 115.700 69.781 109.800 101*40Q_. ..-2A-.MA45.721 96.900 39.097 91.100 34.133 83.800  61.660  30.246  56.800 50.900 46.300  24.184 23.263 21.993  42.766  2.6A* 3.244 4^356 5.213 5.267 5.390 5.246 9.466 1.5.816 8.719 8.795 5.711 4.315  2.6a*  5.327 ,9.683 14.896 20.163 25.914 50.809 40.275 56.091 64.810 73.603 79.316 B3.631  6.461 6.163766 6.481 13.784 0.402706 7.303 21.531 0.693472 7.747 7.689 " 29.220 1.005958 1.185251 6.64 3 35.863 1.364216 5.892 41.754 1.445629 5.147 46.421 2.901679 8.273 59.194 12.838 68.033 12.707710 6.802 74.835 '7.170174 7.384313 6.600 .01.433 2.460846 4.052 85.4B6 2.949 " 88.436 ""1.600332.  0.900 0.650 0.800 0.750 0.700 0.690 0.600 0.550 0.500 0.480 0.460 0.440  13.990 13.770 13.630 13.500 13.350 13.200 13.050 12.880 12.180 11.350 ' 9.700 9.120 B.34'6™ 7.620  U.65Y  0.305 0.500 0.68D 0.915 1.150 1.391 1.678 3.078 4.793 8.297 9.393  16.752  11.848  0.009073 0.011452 0.018016 0.032332 0.043869 .  6.641767  0.092633 0.953067 1.924619 4.203511 1.400362 6.44S420 0.689022  DRYING 0.900 0.850 0.800 0.750 0.700 0.650 0.600 0.550 0.500 0.480 0.460 0.440 0.400 0.350  120.8~00 115.700 109.BOO 103.400 96.900 91.100 65.BOO 81.000 73.600 62.BOO 56.800 50.900 46.500 42.700  .  85.838 60.507 46.774 38.052 31.972 27.462 23.961 21.147 19.435 18.573 17.765 16.657 15.145  2.552 4.334 6.302 8.112 8.729 9.408 9.817 19,405 34.939 18.963 19.445 10.261 6.134  . 7.066 0.210327 19.526 0.495702 25.034 0.914266 34.992 1.413556 43.995 1.75993 8 52.328 2.133446 59.916 2.450365 73.153 5.229524 95.058 24.581726 106.420 13.629292 117.563 14.240433 123.687 3.053422 126.084 1.884160  -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 pore volume rrilST-rH  separation... A 0.960 0.928 0.B82 0.814 0.760 0.6BB 0.609 0.558 0.515 0.496 0.484 0.461 0.424  231.340 214.070 193.760 168.180 151.680 135.810 122.080 115.330 109.620 102.830 93.140 81.707 74.746  211.753 126.B41 81.542 58.062 45.885 36.550 30.874 27.768 25.964 25.148 24.294 22.931  2.902 5.549 10.567 9.211 10.716 11.137 6 . 063 5.676 8.227 12.62 5 14.892 8.282  2.902 8.451 19.018 28.229 38.945 50.082 56.145 61.821 70.048 82.672 97.564 105.846  19.824 22.704 27.795 17.252 15.862 13.131 6.038 5.084 6.890 10.242 11.670 6.126  19.824 0.175752 42.528 0.398103 70.323 0.828020 87.575 1.286317 103.437 1.446940 116.568 1.703544 122.606 1.657203 127.690 1.978267 134.581 6.646103 144.822 17.196516 156.492 10.486257 162.618 3.796562  PULP BEATEN I MINUTE —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0.666 0.818 0.754 0.671 0.5B2 0.493 0.4B2 0.436 0.382 0.315  168.571 152.025 136.206 121.930 110.861 97.540 86.481 71.410 64.693 58.647  107.266 76.819 58.257 44.356 34.549 27.977 25.021 23.697 21.566 19.315  7.685 8.037 9.712 10.874 10.105 15.303 16.075 21.451 8.223 6.884  7.685 15.722 25.434 36.308 46.413 61.716 77.791 99.242 107.466 114.349  26.591 19.916 18.251 15.559. 11.262 13.811 12.975 16.396 5.721 4.289  26.591 0.669136' 46.507 0.941393 64.758 1.143060 80.317 1.314577 91.579 1.447955 105.390 2.573365 118.364 23.795410 134.762 7.802487 140.463 2.647841 144.772 1.832177  PULP BEATEN 5 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION; 0.849 0.778 0.677 0.586 0.545 . 0.495 0.472 0.460 0.429 0.394 0.359  158.952 134.210 113.126 99.946 94.770 88,735 76.865 72.547 66.612 62.755 59.575  105.750 66 8 8 5 4 7 208 3 5 119 29 6 5 1 26 7 9 2 24.B29 23.990 23.027 21.640 20.297  15.554 13.330 14.969 11.675 5.056 6.550 16.765 6.048 7.812 4.466 3.544  15.594 28.884 43.653 55.528 60.564 67.133 83.898 89.946 97.757 102.224 105.768  53.059 26.760 22.793 13.227 4.836 9.660 13.428 4.680 5.803 3.116 2.321  93.059 0.972994 81.819 1.239752 104.614 1.410968 117.641 1.649013 122.677 1.658871 128.337 2.018490 141.765 11.981253 8.379172 146.445 1,32.247 4 . 2 4 5 2 2 5 2.214919 135.365 1.816641 157.686  PULP BEATEN 9 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION, 0.903 0.B36 0.729 0.622 0.533 0.493 0.467 0.439 0.407 0.372 0.281  154.304 125.339 102.931 90.496 83.596 80.596 69.880 62.159 58.344 55.601 48.940  95.282 59.696 39.855 30.634 26.399 24.659 23.399 22.099 20.778 18.601  11.932 13.671 10.245 6.627 3.258 > 15.697 11.368 5.02 7 3.268 8.389  11.932 23.603 35.848 42.475 45.732 61.429 72.797 77.824 81.092 89.481  36.675. 26.326 13.171 6.548 2.774 12.486 8.581 3.384 2.191 5.034  36.679 63.001 76.172 82.721 89.499 97.981 106.561 110.145 112.336 117.369  0.639579 0.957*48 1.080315 1.047964 1.248110 9.935542 6.797977 2.676693 1.661089 1.649734  PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0.948 0.8SB 0.824 0.691 0.610 0.560 0.517 0.474 0.449 0.421 0.392 0.358  191.314 151.048 127.255 100.965 91.082 B5.749 81.672 69.443 64.368 60.923 58.087 55.191  156.118 85.632 54.489 36.780 30.965 27.892 25.471 23.771 22.599 21.437 20.233  9 . 392 9.561 15.539 7. 820 4.855 3.964 15.441 6.477 4.125 3.316 3.303  9.392 18.954 34.493 42.313 47.167 51.131 66.572 73.049 77.174 80.489 83.793  47.301 26.412 27.313 9.278 4.649 3.567 12.687 4.967 3.007 2.293 2.156  UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE ORYING,  pore voL Apore volume  47.301 73.713 101.026 110.304 115.153 118.720 131.406 136.373 139.380 141.673 143.828  0.446094 0.755941 0.998792 1.149426 1.362729 1.377726 5.632641 4.324271 2.515997 2.030772 1.6866P6  separation A 0.824 0.754 0.662 0.611 0.561 0.517 0.477 0.445 0.405 0.368  3.013 2.932 2.828 2.604 2.730 ' 2.686 2.413 . 2.083 1.697 1.809  85.087 59.325 45.004 36.255 31.019 27.886 25.543 23.766 22.187 20.660  pore *TM ;  sum of ™ pore, are* iq-m/fr  pore .YoM-nt!  0.077 0.051 ' 0.085 0.016 0.086 6.053 0.406 0.521 . 0.290_ 0.126  0.077 0.126 0.213 0.230 0.316 0.369 0.773 1.296 1.586 1.712  0*212 0.097 0.124 0.019 0.086 0.048 0.334 0.400 4.207 0.084  ;  sum of pore vol & » » » 0 . 4 0 6 1(27 0.212 0.309 0 . 0 0 3 . 80 .. P , A U - . 0 . 0 X 1 4 2 * 0.432 0 . 0 0 2 89 0.536 0.023 0.586 0.018 • 5 0.920 0.161 4l 1.320 0.268! 35 ...1*52.7- 0,124 1 . 6 1 1 0 . 0 6 0 TO  UNBEATEN PULP SHEETS WITH 5.5% MOISTURE PRIOR TO SOLVENT EXCHANGE ORYIIWj 0.902 0.840 0.765 0.671 0.605 0.540 0.495 0.469 0.437 0.404 0.353 0.282  4 . 740 4.548 4.429 4.310 4.209 4 . 107 3.774 3.356 2.B94 2.677 2.47B 2.216  187.369 95.540 63.478 45.430 35.437 30.133 26.663 24.784 23.421 22.012 20.374 18.257  0.080 0.067 0.056 0.079 0.087 0.103 0.414 0.561 0.644 0.295 0.259 0.369  0.080 0.147 0.205 0.264 0.371 0.474 0.688 1.449 2.092 2.368 2.647 3.016  r  0.481 04207 0.119 0.116 0.100 0.100 0.356 0.449 0.486 0.210 0.171 0.218  0.481 0.667 .. . . P J 9 » 0.922 1.012 1.122 1.476 1.92* 2.413 2.822 2.793 3.010  0.003392 0.004926 0.008352 0.0009*0 0.01*229 0.0223*3 041*314* 0.353186 0.333940 0.1*4107 0.068993 0»0«3*TI  UNBEATEN PULP SHEETS WITH H.4% MOISTURE PRIOR TO SOLVENT EXCHANGE ORYING 0.971 0.913 0.833 0.764 0.673 0.596 0.542 0.504 0.477 0.458 0.439 0.393 0.344 0.291  14.745 h.O60 13.735 13.585 13.275 13.039 12.229 11.082 9.843 9.061  247.108 100.281 61.832 45.449 33.175 29.836 26.949 25.183 .24.058 23.191 21.836 20.007 18.247  0.096 0.105 0.073 0.214 0.203 0.191 0.746 1.485 1.672 1.066 1.133 0.885 0.936  0.096 0.201 0.274 0.486 0.691 0.882 1.628 3.114 4.78* 5.852 6.983 7.870 8.826  0.764 0.339 0.146 . 0.314 0.231 0.164 0.649 1.207 1.298 0.798 0.798 0.571 0.5*3  6.7*4 1.103 JL 2*3 1.9*3 LT94 1.97T 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*  UNBEATEN PULP SHEETS WITH 33j6% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING] 0.915 0.836 0.765 0.712 0.638 0.575 0.531 0.492 0.460 0.466 0.397 0.347 0.274  122.494_ 114.326 103.131 98.132 89.652 83.274 78.957_ 71.256 62.784 55.386 46.333 42,619 37.696  102.722 62.445 47.918 39.34* 32.686 28.783 26.339 24.975 24.326 22.518 20.145 16.048  3.062 5 . 474 5.250 7.483 6.486 4.853 10.087 12.23B 10.766 12.030 4.343 5.941  3.062 8.336 13.766 21.268 27.754 32.607 42.694 54.932 65.698 77.728 82.070 88.011  10.14* 11.02* 8.115 9.497 6.839 4.506 8.569 9.660 8.448 8.738 2.822 3.459  0.1*8126 10.14* 21.173 0.545702 29.288 0.9i722*_ 1.144*52 36.785 4 5 . 6 2 4 1.36293* 5 0 . 1 3 0 1.613*30 58.699 4.070622 68.556 16.059692 77.00* 12.34130* 65.745 2.961400 1.5534*7 68.5*6 9 2 . 0 2 5 1.4560*2  -229-  ! TABLE 2 CONTINUED  cnihmcAL PORE MODEL;  _jW6EAT£W PULP — SOLVENT  EXCHANG£  CYLINDRICAL  DRIED FROM WATER SUSPENSION  UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE DRYING diam. of port  port vol 0.887 0.824 0.754 0.682 0.611 0.561 0.517 0.477 0.449 0.405 0.368  fPULP BEATEN j MINUTE —SC^VENT^EXI^Aft^ JRlED FROM WATER SUSPENSION  ! 0.754 0.671 0.493 ; 0.482 JJU436_ : 0 . 382 0.313  189.839 168.571 -142.025136.206 121.930 "0.861  96.134 9.289 9.289 . 26.805 67.149. . 10.554 . 19.842 .22*060 49.703 14.062 33.903 22.546 36.806 17:585 51.490 20.680 27.846 1 6.02 0 69.309 16.186 97.340 21-93831.406 100.916~ 22.226 86.481 19.309 36.367 437.263 22.652 _11.410 _ ...IB.147... ..48.602 169.965 ..28.498 64.693 .16.287t 14.391 200.356 7.561 58.647 14.344 6.799 209.153 4.071 1  iim  2B.805 0.758395 51.666 1.143702 74.212 1.512766 95.091 1.917999 111.278 2.299764, 133.503 4.652602 156.156 47.125031 184.694 15.461434 192.213 4.027889 19&.266 2.025726  IPULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATERSUSPENSION ,0.915 201.653 0.849 138.952 94.737 19.379 19.379 59.222 59..222 1.137102: 1134. 2 1 0 _. ... 37.8Q1„ .13.674... .-38,Q53_. „34»ei9 94, 041 1.396022 foT677. 39.492 113.126 24.076 62.129 30.639 124, 661 2.034814 .0.348 28.365 20.708 82.636 16.946 143. 626 2.607203 0.545 33,42,5 "««9 6.664 150. 490 2.632114 ? t P W 0.499 20.678 104.603 8.344 159. 034 3.439166 12.666 !0.472 19.141 76.865 142.764 36.179 23.374 182. 23.677365 ..HV460 _ _T2»5AI„ _ i e . . 4 0 2 „ ..13.488._. .156.272.. . . 8 . 0 0 7 , 190. 606 614 16.324631i 0.429 17.559 66.612 172.782 16.510 9.351 199. 966 7.822379 0.394 16.350 62.753 7.642 160.424 4.031 203. 996 3.294692 (0.359_ 15.186 39.575 5.282 185.707 _ 2.586 206. 584 2.3464461  (PULP BEATEN a MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 64.724 51.094 32.686 24.315 20.529 69.880 18.991 62.159 17.883 3 8 . 1 4 4 . _ . 16.749 55.601 15.602 46.940 13.734  (NjLP 07948 - O . m  14.930 I0U37„ 17.176 11.846 6.Q4^ 35.440 25.696 I_9,B37 9.161' 14.075  -J»>4? ,0.474  J-***  0.421. 0.392 0.336  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 ,.711 1.802 1.315 :.598 .236  40.805 0.981270 74.027 1.293842 92.138 1.625899 101.431- 1.658458 103.433 2.032911 127.144 19.624191 141.946 13.386587 147.260 4.357436 149.858 2.303163 156.093 2.39099-6  BEATEN N> MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION ' '—" \ " 11.41. 11.419 3Z.TT1 32.771 24.414 32.150„_ 64.921 100.965 46.249 , 26.068 90.702 3B.920 123.841 91.082 29.869 14.120 .64.821 13.609 117.446 M ' T W 9,>9| 74.012 7.293 144.740 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 69.443 19.708 36.491 116.212 23.199 173.374 64.3M__16.210 14.847. — 133.106 8.751 . ^102.129 60.923 17.165 . 8.566 141.694 4.759 186.884 56.087 16.173 A 6.409 148.103 3.343 190.228 53.191 1 S . U L 9.76*. 193.369 .2.824 193.052  191.314 131.049  '• 143.2.2  :•••*£*-—;JJ>233„„„75.330___ U . 1 9 J :0.691 :0.6l0  3.177 3.013 2.932 2.828 2.804 .730 2.6B6 2.413 2.083 1.897 1.809  75.009 50.706 37.400 29.388 .24.653 21.B50 19.772 18.206 16.826 19.500  tun of pore amWry* 0.097 . 0.070 . 0.133 04 022 0.162 0.101 0.886 1.182 0.634 0.227  \dumr.  port vol  ^ port volumt £port Uzt  0.235 0.350 0.511 0.532 0.660 0.731 1.296 1.990 2.335 2.448  0.007392 0.006832 0.016373 . 0.003346 0.039267 0.030396 0.309792 0.531795 . 0.236660 0.094998  rrt.JST.EVV 0.097 0.167 .0.301 0.585 1.471 2.693 3.287 3.314  0.233 0.115 0.161 0.021 0.129 - 0.071 0.565 ' 0.694 0.344 0.113  7.043699" 3.2813831 3.213002.  0.386  0.911 JO. 8 6 6  PORE MODEL'  T 0.319723 0.970146 '1.930910' 1.394366; 2.2636941 2.358657 11.6651161 8.664138 4.561789 3.410607 2.660533  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 0.540 0.495 0.469 ' • 0.437 0.404 0.351 0.262  5.158 4.740 4.348 • 4.429 4.310 . 4.209 4.107 3.774 3.356 2.894 2.677 2.478 2.216  173.578 64.963 54.605 37.823 28.644 23.B60 20.763 19.101 17.904 16.674 15.254 13.436  0.096 0.092 0.084 0.139 0.171 0.217 0.997 1.403 1.645 0.692 0.511 0.773  0.096 0.187 0.276 . 0.416 0.586 0.603 1.800 3.203 4.848 5.540 6.051 6.624  0.536 0.251 0.157 0.170 0.158' 0.167 0.667 0.865 0.950 0.372 0.292 0.335  0.936 0.787 0.944 1.114 • 1.271 1.438 2.106 2.970 3i920 4.292 4.544 4.879  0.003904 0.006291 0.007535 0.013295 0.0282611 0.041863 0.302630 0.772381 0.744710 0.314060 0.152034 0.169629  UNBEATEN PULP SHSETS W]TH 14.4% MOISTUREPRIOR TO SOLVENT EXCHANGE DRYING "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 _16.52;  " 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 0.003799 1.295 0.007841 1.493 0.011008 1.979 0.038987 2.357 0.099924 2.672 0.0970401 3.909 0.638647 . 6.291 1.999609' 6.891 9.294147 10.460 2.144168 11.906 _0.886983 6.607625 0.620469  UNBEATEN PULP SHEETS WITH 3 3 j S % MOISTURE PRIOR TO-SOLVENT" EXCHANGE DRYING T.913 • 122.494 , •0.836 114.326 0.765 103.131 0.712 98.132 0.638" 89.632  . * 91.877 53.630 40.082 32.206  "~ " 3.694 3.894 7.918 _ 11.812 8.228 20.040 12.926 32.965  ''" ' 11.541 13.697 10*639 13.42B  0.531 0.492 0.480 0.466 0.397 0.347  22.650 20.472 19.269 IB.698 17.118 15.056  9.397 21.752 27.642 24.555 24.776, 5.805  6.866 14.364 17.306 14.810 13.681 2.820  78.957, 71.256 62.7B4 55.386 46.333 42.619  54.367 76.119 103.961 126.515 153.292 159.097  3.139  11.341 25.238 35.877. 49.306  ~  ' 0.200457 0.723944 1.301324 1.772614 _  66.301 2.755214) 80.665 7.704779 97.971 31.9806811 112.761 24.606400' 126.463 9.349516 129.282 1.799486  132.421  1.931132  -230-  TABLE 3= PORE ANALYSIS USING STANDARDIZED ARGON. ISOTHERMS  UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  .ttparation, 190.000 0.850 176.000 0.800 164.000 0.T50 154.000 0.700 145.000 0.650 -._L37.QI-Q_. •0___Q1. • 130.000 0.550 122.000 0.500 114.000 0.450 106.000 . 0.400 102.000 0.380 Q, 370 83.000 0.360 75.000• 0.350 71.000 0.340 68.000 0.330 62.000 0.300 P  I  A  ;  113.452 80.045 62.329 51.242 43.546 ".7Qfl 33.274 29.634 26.623 24.075 22.467  5.273 6.082 6.675 6.731 7.018 7.nr.A 6.762 8.752 9.587 10.530 5.584  21.405 21.001 20.609 20.227 14.492 • B-nq'i  24.230 12.874 6.278 4.629 8.916 7-460  5.273" 11.355 18.030 24.760 31.778  *A.7«*.  45.548 54.300 63.888 74.418 80.002 110.313 123.187 129.465 134.094 143.010 1*0.964  155.000 144.000 134.000 126.000 118.000  •0.550 0.500 0.450 0.400 0.380  -Lll.imCL. 105.000 99 . 000 93.000 87.000 84.500  0.360 0.350 0.340 0.330 0.300  78.000 68.000 64.000 61.000 55.000  113.452 80.045 62.329 51.242 43.546 37 ,70ft 33.274 29.634 26.623 24.075 22.467 .820 21.405 21.001 20.609 20.227 19.492 tfl, n m  4.032 4.780 5.571 5.385 • 6.268 -160 5.815 6.497 7.120 7.829 3.372 8.736 16.389 6.425 4.778 9.383 6_B68  4.032 8.813 14.384 19.769 26.037 -09. 38.012 44.509 51.628 59.457 62.829 -JL3.472.890 B9.279 95.704 100.482 109.865 - ..116 .733  FRC^ATJR SUSPENSlC^l  t u r n of __ por* v o l u r m • • pore v o l £por» v z t rr_&T% "19.298" " 1 9 . 2 9 8 " 07432126 15.703 35.001 0.708755 1 .010895 13.421 48.422 1.250404 11.125 59.547 1 .517764 9.859 69.406 7fl2a' a__J4.3... 7T 94' 7.258 1.808181 85.206 2.560570 8.367 93.573 8.234 101.807 2 .990491 3.490779 8.17B 109.985 4.629946 4.047 114.032 14]R4Q ___LB_, 135.042 40.696132 143.764 21.868790. 147.938 10.814788 150.958 7.986792 3.020 156.564 5.606 5.133451 4-646 lhl.Plfl T  PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION • 0.850 0.800 0.750 0.700 0.650  PU^JJEATJUUJjINU^  port ' ..vdijrnt;  14.757 12.344 11.201 B.901 8.805 7.510 6.241 6.210 6. 114 6.080 2.444 . —0.932 6.032 11.103 4.271 3.118 . 5.900  14.757 0 . 3 3 0 4 5 0 : 27.101 0.557118 38.302 0.843714 47.203 1.000407 56.008 1 .355575 63.518 -1.496844.1 69.759 1 .554899! 75.969 1.900644 82.084 2 .220694, 88.164 2.595457 90.608 2.795746 I .540 2.22001,9 ; 97.572 14.744 889 108.675 27.839462 112.946 11.068015 116.064 8.245047 121.964 5.402268 125,37 _• 2.355616  PULP BEATENflMINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION, 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 77.000 71.000 61.500 58.000 53.000 -_5J.00Q—  113.452 80.045 62.329 51.242 43.546 -18033.274 29.634 26.623 24.075 22.467 21.405 21.001 -20.609 20.227 19.492  2.792 3.038 3.335 4.057 3.906 -3-684 •  10.217 7.844 —WTO*— 6.706 5.487 20.612 •4.247 4.177 3.892 24.504 4.154 4.346 28.850 -3.436 - 32.286 - — 2 . 9 3 1 5.259 37.544 4.084 . 3.572 41.116 2.589 -??9 43.3__.., \ 46.431 3.085 .130 56.252 9.821 6.653 -15-935 . - . 7 2 - 1 8 7 - ~L0.594 3.752 77.937 5.750 4.967 85.836 7.900 93-3X2 . A.-3A* , 7-ATA 9.1*5-  10.217 0.228773 16.061 0.354043 -24.^67—0,6.3142 31.473 6.753715 36,960 0.844739 -61.207.—0.646604 45.384 1.040691 49.539 1.271599 -52.489 1.071601 56.573 .743307 39.162 1.961574 .7^1 62.862 207555 6 9 . 5 1 9 16. 6 6 2 T 8 5 1 0 9 - 2 7 . .4499218 3 . 8 6 0 . 9.,9 2 1 1 2 4 , 68.827 4, 548265  PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0.850 136.000 0.800 126.000 0.750 118.000 0.700 110.000 0.650 103.000 -0.600— . 9I_DflO_ 0.530 92.000 86.000 0.500 81.000 0.450 77.000 0.400 75.000 0.380 7*_f>i-n n.^7n .360 69.000 0.350 64.000 0.340 96.500 0.330 56.000 0.300 51.000 Q-"0 4h.nm.  113.4S_  60.045  62.329 51.242 43.546 »7,70ft 33.274 29.634 26.623 24.075 22.467 ______ 21.405 21.001 20.609 20.227 19.492 lA-ftOt  3.412. 4.351 4.447 5.409 5.481 4.818 6.581 5.883 5.013 2.669 7 -Q7Q 6.309 8.075 9.060 3.982 7.819 7.331  3.412 7.763 12.210 17.619 23.100 2ft.__.B-. 33.186 39.767 45.690 50.663 53.332 .62.620 70.695 79.756 83.738 91.557 ,. .9B_jaa_  12.487 12.487 11.234 23.721 8.942 32.662 8.942 41.604 7.698 49.303 -__.A215.171 60.895 6.291 67.187 5.052 72.239 3.893 76.132 1.935 78.067 ?-tl47 4.356 84.520 5.471 89.991 6.023 96.014 2.598 98.612 4.916 103.528 4.?79 __07.aQJ_  0.279611' 0.507019 0 . 673 344 1.004974 1.185202 1. _anna?' .288375 1.929439 1 .834891 1.661850, 2.213162 4.99^H_f 10.649177 13.716990 15.607324, 6.870851 4.501869 7-H-l.nV  UNBEATEN PULP SHEETS WITH 5.3% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING i  .6.650 , 0.800 0.750 0.700 0.650 ft *,nrt 0.550 0.500 0.450 0.400 0.380  n . M 0.360 0.350 0.340 0.330 0.300 0.2S0  5.380 113.452 5.290 80.045 5.220 , 62.329 5.140 91.242 5.050 • 43.546 _.9hn »7 . i o n 4.860 33.274 29.634 4.740 - 4.610 26.623 • 4.440 24.075 ' 4.340 22.467 1 n.ft -jA.n 321.405 4.030 3.920 21,001 3.280 20.609 3.020 20.227 2.630 19,492 lfl.ns . .nan  _  7  1  0.037 0.039 0.039 0.054 0.071 ft. n f t i 0 . 101 0.136 0.162 0.235 0 . 146 n . ]•}«. 0.339 0.511 0.740 0.438 0.655 ft. 1^7  0.037 0.076 0.115 0 . 169 0.240 n i n 0.422 0.558 0.720 0.953 1.103  0.136 0. 101 0.078 • ,0.090 0 . 100 n nan 0.108 0.130 0 . 139 0.183" 0.107  3KQ n 1 in 0.234  i 1.596 - 2.109 2.849 3.288 3.943 4.4Hft  0.346 0.492 0.286 0.412 n - i -  0.136 0.237 0.315 0.405 0.509 0.711 0.841 0.480 1.163 1.270 1.614 1.960 2.452 - 2.73B . 3.150  0.003050. 0.004549  6.'005877  0.010065 0.019403' n n l ifif] ft 0.026949 0.039751; 0.050496, 0.078067) • 0.122599 ft 5*1^^7 0.572136 0.868148 . 1.275068! 0.756222 ' 0.3 77090 n i«_i_7  UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT PfCHANGE DRY-MO 0.850 0.800 , 0.750 0.700 0.650 n .Aftft 0.950 0.500 0.450 0.400 0.380 0.^70 0.360 0.350 0.340 0.330 0.300 n.?50  3.500 113.452 3.420 80.045 3.350 62.329. 3.290. 31.242 3.230 . 43,546 * . i»\n »?.7an 3.090 33.274 3.010 29.634 2.920 26.623 2.820 24.075 2.760 22.467 p_7.n ?1.RJft 2.360 21.405 2.300 21.001 2.0B0 .20.609 . 1.960 20.227 1.730 19.492 1.51(1 lA.tV) . 1  0.022 0.035  ...-0*039..0.041 0.047 0.070  0.022 0.057  0.079 0,090 0-096 — . _ ~ o ; o 7 9 _ 0.136 0.067 0.183 0.066 n.nil ft_.__. 0.316 0.075 0.066 0.406  0.090 0-518 . . . - . 0 * 0 9 6 - , 0.635 0.106 0.088 0.743 0.064 ft.07T n.H7n n.n«i_ 0.210 1.030 0.143 0.464 1.493 0.314 0.366.. -...-1.661 .— — 0 - 2 4 5 — 0.200 2.061 0.130 0.349 2.410 0.219 0.40? n.3*«,  -.0.112 _ 0.137  0.079 0.00frf79> 0.170 0.0040681 0.246. O.005<16 0.315 0.007529 0.381 0.010202 ft. _*.•>. ft.nl«?7ft 0.333 0 * 0 1 6 7 6 2 0.619 0*026320 0-7130.821 0.045344 0 . 8 6 5 0*072942 n - « 4 n ft.'19Q-AN 1.064 0.333679 1.398 0.787340 1 * 6 4 3 -. .0 . 6 3 6 2 5 8 1.773 ;0V344849 1.993 0.200721 2.771  -231-  TABLE 4: PORE ANALYSIS USING EXPERIMENTAL VALUES OF ARGON ISOTHERMS  UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION Mil separation, •' A  sum of port am  •  J  "0.699 0.878  219.765 206.214 123.049 190.65S 183.564 __?*•«+_ 72.542 171.219 0.782 56.633 157.697 0.718 : 44.760 164.204 0.645 16.768 134.013 0.581 31.267 123.740 0.515 _U'.Sf.m_ ,27.373 24.530 107.930 0.407 22.344 101.229 0.376 21.677 91.638 0.367 21.148 7*.5*3 0.351 i0.304  8TH  port  t  volume', • rrH(ST^  2.9U 2.914 2.013 4.927 _**066 _ _ 9 . 9 9 3 5.503 15.496 7.706 23.202 9.583 32.785 —a.127 41.312 9.952 51.264 8.396 _ . 5 9 . 6 6 0 9.1688 67 98 .. 32 42 96 "" 8.878 92.452 14.226 116.790 24.338 135.008 145.564  20.652 7.990 15.828 12.877 " 14.078 13*837 10.096 10.037 7.414 7.666 6.456 9.948 16.619 11.740 6.106  0.284 0.239  T597T29" 152.376 93.722 138.320 _72.916 127.261 94.707 118.573 44.411 111.834' 38.277 104.210 S3.512 98.338 29.413 93.523 _ 26.605 67.931 24.363 63.442 22.410 76.419 21.424 Tl.174 21.113 66.170 20.793 584988 20.178 _ 51.942 19.073 49.693 17.636  "3.704 2.656 6. 538 6.604 6.502 5.739 7.159 6 i 173 5.559 ""fiOl* 5.920 7.782 111 526 7. 894  J1.258 10.933 1.477  -  3.704 6.360 _12.698 19.703 26.205 .944 39.103 454 276 50.833 '37.849 " 63.769 71.531 83.077 90.971 102.229 113.163 " 114.640  U.STT 8.030 13.379 12.008 9.315 7*066 7.75ft 3.8*7 4.771 " 5.512 4.260 5.378 7.850 5 . 295 7.328 ' 6.726" 0.840  0*6.  port vol A port volume ml(5.TJ^. A P °  re  20.652 0.12&405 28.642 0.366631 44.470 0.517309 57.347 0.714308 71.425 1.020822 63.262 1.390086 95.35B 1.640137> 105.396 2.1260*1, 112.610 2.417480 120.476 2.926713 126.932 4.778172 136.880 25.982265 15B.498 26.098557 165.239 6.733957 171.345 2.601652  PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION •0.847 . . 0.038 0.773 0.710 0.652 0.608 0.548 ,0.495 JU+55 0.407 0.370 0.361 0.354— 0.345  PULP BEATEN I MINUTE —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  turn of  16.577 0 . 2 3 0 1 4 6 24.607 39.966 0.650933; 51.993 0.936689 61.308 1.194100 66.394 1.566390 7 6 . 1 3 0 I T 575423 62.007 1.714727 86.778 2.168190 92.290 2.414121 96.570 2.638865 101.948 15.32*733 109.798 ZS.681998 115.093 14.3935*4 122.420 8.499576 129.146 5.007702 129.968 0.54901*  : 0.926 0.873 .0.833 0.799 0.724 0.654 0.599 0.543 0.467 0.423 0.385 0.369 0.362 0.355 0.348 0.326 0.291. 0.248  183.964 170.151 161.673 154.834. 141.854 132.261 125.743 116.742 111.826 104.295 99.167 93.538 88.651 80.378 72.299 63.463 5B.079 . 53.169  wall separation  pore area  .* 250.627 —1.092 145.030 3.135 94.542 2 . 894 75.306 2.930 59.595 7.040 45.674 6 . 666 5.284 37.954 6.456 32.972 7.187 28.979 8^747 23.375 6.525 23.089 8.027 21.899 0.264 21.424 1 1.656 21.139 12.444 20.856 13'. 348 20.303 7.532 19.263 6.357 17.903 _  sum of pore area  pore volume mLfST.r^9.  sq-nyg. —1.092 4.227 7.121 10.051 17.091 23.756 —29.040 35.496 42.683 51.430 57.956 65.983 74.189 85.845 98.268 111.637 119.169 125.526  "  8;826 14.666 8.826 T . 118 13.534 9.821 —6.470 6.866 6.719 7.217  7.94B 8.372 8.742 4.680 3.672  sum of pore vol 8.826 23.492 32.318 39.436 52.970 62.791 69.261 76.128 82.846 90.063 94.923 100.594 106.265 114.213 122.584 131.327 136.007 139.679  £ pore volume 0.0652TB 0.193009 0.353211 0.527899 0.754452 0.991824 1.170345 1.544022 1.899162 2.206676 2.655702 6.353747 20.924576 26.675348 31.421722 10.420931 3,767006 2.493928  PULP BEATEN 8 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION O;BT3 o.Bia 0.746 0.680 0.555 0.472 0.398 0.360 0.349 0.339 0.308 0.272 0.226  12*9; 9 20 121.891 112.359 105.090 94.227 88.321 82.676 76.878 67.317 60.634 54.091 30.199 46.9*4  139.298 ' 91.454 65.247 49.490 37.646 29.029 " 24.602' 22.007 20.990 20.570 19.796 18.606 17.247  1.919 3.003 4.949 4.951 9^357 6.307 7.067 8.403 15.064 11.186 10*. 318 5.84B 5.966  1.919 4.924 9.673 14.824 24.161 30.468 37.555 45.958 61.022 72.208 82.526 86.374 92.334  8.6l5~ 8.864 10.416 7.904 11.423 5.906 5.609 5.965 10.200 7.422 6.589 3.510 2.203  8.^2? 0.135047 17.489 278568 27.905 305772 35.809 723700 47.232 923656 53.138 120676 5 8 . 7 4 7 — T 5*461fl 6 4 . 7 1 2 3 .716944 74.912 23, 721100 8 2 . 3 3 4 18. 078720 88.923 794353 92.433 824673 94.636—1.492478  P U L P BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION TJ.673 0.631 L0.774_. 0.729 0.666 0.609 0.362 0.505 0*45,5 0.418 0.374 0.3*1 0.352 P.3*0 • 0.311 0,270  141.240 177.212 3.365 3.365 14.234 14.234 6.137901 131.964 94.409 3.366 6 . 7 5 1 • 10.311 29.550 0.394986 121.672_ 71.312 4..S54 11.306 10.476 40.026 0.521747 113.894 56.361 4 . 3 3 1 15.836 8.240 48.267 0.842241 105.092 46.843 6.093 21.930 9.208 57.474 0.990960 98.233 »-' ? 5.504 27.434 6.944 64.423 1.133984 93.076 34.101 : 4.657 557091 5 . 1 2 3 69.545—1.301343 .86.955 30.220 .6.177 38.266 6*022 75.567 1.573985 82t346 26.895 5.040 _ 43.308 4.372 79.939 1.348065 78.544 ' 24.600 4.622 47.930 3.668 1 83.607 2.077659 74.12* 22.756 5 . 6 1 4 53.544 4 . 1 2 1 87.728 2.143791 69.318 21.312 7 . 1 2 0 60.6*3 4 . 9 4 1 92.669 8.713852 64.834 21.0*6 67TC3 67.512 4.649 97.318 12.72*172 58.414 20.635 10.009 77.521 6.663 103.981 14.646826 53.037 19.876. 8.040 65.961 __3.13S 104.136 4.842194 46.153 16.637 7 . W 6 . 92.7*7 "~ 4.326 113.4*2 3.060341 3  3  'UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE DRYING ""0;«&T 0.6*2 0.7T0 0.710 0.673 , 0.599 6.53Y 0.479 0.435 0.419 0.390 0.364 6.355 0.347 0.33* OH, 3 1 1 0.265  "37576 190J6O3 3.476 . 112.027 73.557 3.380_ 54.333 3.299 45.682 3.263 39.154 3.150 32.747 3.673 28.591 2.977 25.659 2.685_ 24.040 2.863 23.035 2.787 21.915 2.6*6 21.18V 2.446 20.646 2.226 20.480 2.044„ 19.799 1.606 18.950 1.565  0.016 0.030 _ 0.043 0.6*9 . 0*.0250~.094 0.073 0'. 106 0.113 0.027 6 . 104 0.176 0.3*3 0.347 0.3B5 0.391  ~0":016"" 0.045 a_ 0.1370.163 0.256 0.330 0.435 0.549 0.575" 0.660 0.856 1.140 1.546 1.826 2.211 2.602  0.0a  0.646 0.107 0.102 • 0.086 0.037 0.118 O.078 0.098 0.094 0.021 0.077 0.125 0.234 0.234 0.185 0.246 0.234  0.000902 0.64* 0.203 - 0.002112 0^003877 „0.305 0.007085 0.391 0.007238 0.428 0.014964 0.547 0.016106 0.62* 0.027186 0.722 0.041179 0.815 0.022486 0.836 0.068781 0.914 0.111920 1.038 0.660324 1.272 0.751127 1.306 0.435701 1.691 0.259921 1.437 0.151492 2.171  UNBEATEN PULP SHEETS WITH 5.3% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING 0.863 ' 0.789 0.718 0.646 0.583 0.524 0.483 0.447 0.411 0.387 0.361 0.345 0.336 0.321 0.290  5.394 5.274 5.165 5.034 4.929 4 . 801 4.693 4. 594 4.478 4.392 4.090 3.557 3.166 2.845 2.551  144.112 82.390 57.349 44.749 36.810 ' 31.659 28.260 26.048 24.245 22.854 21.787 20.938 26.445 19.980 19.146  6.643 0.049 0 . 064 6.098 0.093 0.132 0.124 0". 122 0 . 154 0 . 119 0.460 0.854 6.640 0.525 0.475  0.043 0.092 0.156 0.253 0.346 0;476 0.6O1 0.723 0.877 0.996 1.456 2.311 2.451 3.476 3.950  0.201 0 . 130 0.118 0.141 0.11O 0.134 0.113 0.103 0.120 0.088. 0.323 0.577 6.422 0.338 0.293  6.201 0.330 0.44B 0.590 0.700 0.834 0.947 1.049 1 . 170 1.258 1.581 2.156 2.580 2.918 3.212  0.0022*6 0.003826 0.007497 0.014349 0.018247 0.031493 0.044461 0.054202 0.070122 0.082559 0.302550 0.916114 1.186599 0.568819 0.267993  -232-  APPENDIX D Table 5: Pore Volumes E x p r e s s e d as B u l k L i q u i d Volumes Unbeaten P u l p S o l v e n t Exchange D r i e d from Water Suspension Nitrogen Analysis Pore Size a  Pore Volume ml.xlO 3  Argon A n a l y s i s  Cumulative Volume ml.xlO 3  Pore Size a  Pore Volume ml.xlO 3  Cumulative Volume ml.xlO  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  3  •  -233-  Table 5 C o n t i n u e d Unbeaten Vacuum-Dried-Solvent Nitrogen Analysis Pore Size  Pore Volume  a  ml.xlO  3  Exchange D r i e d  _  Handsheet  Argon  Analysis  Cumulative Volume  Pore Size  Pore Volume  ml.xlO  a  ml.xlO  3  Cumulative Volume 3  ml.xlO  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  3  -234APPENDIX D Table 6:  Reduced Cumulative Pore Volumes*  Parameter: Minutes Beaten. Beaten 1 Minute  Beaten 3 Minutes  Beaten 5 Minutes  Beaten 10 Minutes  0.223  0.252  0.261  0.250  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  Wall Separation  Unbeaten  96.8  0.155  70.3  *  C a l c u l a t e d from n o r m a l i z e d 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 assuming t h e p a r a l l e l s i d e d f i s s u r e model. The pore volumes a r e e x p r e s s e d as r a t i o s .  -235Table  6 Continued: Parameter:  Moisture Drying,  Content P r i o r t o Solvent  Exchange  Wall Separation  Vacuum Dried  5-3 %  14.4 %  33.6 %  96.8  0.106  0.078  0.038  0.073  0.155  70.3  0.178  0.124  0.061  0.156  0.294  55.6  0.234  0.153  0.082  0.243  0.412  46.2  0.267  0.181  0.106  0.330  0.493  39.5  0.288  0.207  0.130  0.405  0.564  34.5  0.309  0.239  0.153  0.472  0.619  30.6  0. 341  0.272  0.179  0.530  0.664  27. 4  0.416  0.. 398  0.293  0.624  0. 724  25.5  0.531  0.546  0. 429  0.769  0.845'  • 24.5  0. 709  0.682  0.700  0.846  0.910  23.6  0.811  0. 817  0.789  0.921  0.941  22. 3  0. 855  0.925  0.903  0.966  0.972  20.5  1.000  1.000  1. 000  1.000  1. 000  Saturated  -236Table  6  Continued:  Parameter:  Various C e l l u l o s i c Dried  Materials Solvent  Wall Separation a  Regenerated Cellulose (172)  Wood (13)  Cotton (18)  96.8  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  Exchange  - 2 3 . 7 -  APPENDIX E Grades and S u p p l i e r s Chemical  of Chemical Used.  Grade  Supplier  Continuous Flow A p p a r a t u s : He - N N  2  2  Mixtures  (gas)  He  Standard Technical Technical  Volumetric N  Certified  (gas)  Matheson of Canada Canadian L i q u i d A i r Canadian L i q u i d A i r  Apparatus Research  Matheson of Canada  Ar  Research  Matheson of Canada  ° 2  Research  Matheson of Canada  He '  Research  Matheson of Canada  2  Solvent E x t r a c t i o n : Methanol  Absolute  Fisher S c i e n t i f i c  Co,  n-Pentane  Spectral  Fisher S c i e n t i f i c  Co,  Sodium M e t a l  Reaction  Magnesium T u r n i n g s R e a c t i o n  Fisher S c i e n t i f i c  Co,  Liquid Nitrogen  Canadian L i q u i d A i r  Commercial  -238-  APPENDIX F Table 1:  Argon A d s o r p t i o n on Nonporous A d s o r b e n t . ( Z i n c 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  E x p r e s s e d as micrograms/gram  Crystals)  -239APPENDIX P Table  2:  Nitrogen  Standard P/P  G  "Standard"  Isotherm  v/v  Isotherms  o f Payne and S i n g (171) "t"  P/P  0  v/v  "t"  0.005  m 0.632  0.30  m 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,  -240Table  2 Continued: Standard  P/P  Isotherm  m  G  o f L i p p e n s , L i n s e n a n d de B o e r (110) "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  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  9.65  0.32  1.45  5.14  0.78  2.73 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  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  '6.34  0.94  4.94*  17.5*  0.50  1.79 1.84  6.50  0.96  5.59*  19.8*  0.52  1.88  6.66  0.98  6.47*  22.9*  0.24  0.38  *  ,  .  E x t r a p o l a t e d D a t a g i v e n by L i p p e n s , L i n s e n a n d de B o e r  -241Table 2  Continued:  Standard Isotherm 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 equation:  log P/P  (p /p)  "t"  m  G  1 ( J  0  P/P  v/v  0  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  •  -242APPENDIX G TABLE!: CORRECTED DUBININ DATA PARALLEL SIDED FISSURE MODEL > C < £ l  "Via.  UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION 0.00423 0.02669 0.03560 0.07090 0.09330 0.11870 0.16210 0.21550 0,27770 0.32750 0.387BO 0.47360 0.53220 0.62570 0.70180 0.77330 0.81710 0.89790  14.252 30.710 33.514 39.047 41.664 44.411 48.3'2'7 . 53.327 5B.579 63.635 69.692 79.570 B6.B41 101 . 7 2 9 118.505 136.710 150.645 187.589  5.351 17.369 19.696 23.665 25.607 27.718 30.499 34.282 3 8 . 116 41.867 46.374 54.186 59.865 71.363 84.681 98.615 108.336 132.597  5.63426 2 . 4 7 6 38 2.09829 1.32101 1.06114 0 . 8 5664 0.62444 0.44429 0.30961 0.23502 0.16924 0.10536 0.07503 0.04147 0.02365 0.01247 0.00770 0.00219  0.72843 1.23978 1.29438 1.37410 1 . 4 0 636 1 . 4 4 2 76 1.4B429 1.53506 1.58111 1.'62187 1.66628 1.733B8 1.77717 1.85347 1,9277b 1.99394 Z. 03477 2 . 1 2 2 53  PULP BEATEN I MINUTE —rSOLVENT EXCHANGE ORIEO FROM WATER SUSPENSION • 0.00106 0.00350 0.01914 0.05038 0 .07B49 0.12B57 0.17)68 0.22216 0.28177 0.34260 0.40051 0.46480 0.52867 0.62576 .0.70327 0.77779 0 .83650  8.988 15.6*5 27.720 34.617 3B.430 43.226 47.058 5i .107 55.970 61 . 5 3 3 67.219 74.191 81 . 0 3 1 94.532 110.785 128.212 144.768  6.261 8 .092 15.284 20.503 2 3 . 1B1 26.666 29.436 32.361 35.897 39.947 44.056 49,599 54.810 64.877 77.68' 90.637 101.364  6.8468 1 6.03404 2.95141 1.68418 1.22143 0.79360 0.58565 0.42686 0.30261 0.^1642 0 . 15791 0 . 11071 0.07663 0.04145 0.02337 0.01191 0 . 0 0 6 01  0.79667 0.90B08 1.16425 1.31181 1.36512 1.42596 . 1.46887 1.51002 1,55506 1.60148 1.64400 1.69547 1.73886 1.81209 1.89034 1 .95731 2.00588  PULP BEATEN S MINUTES—SOLVENT EXCHANGE ORIEO FROM WATER SUSPENSION 0.00032 0.00285 0.01194 0.01399 ' 0.03100 0.06680 0.10290 0.15190 0.20370 0.26250 0.35100 0.4Z520 0.49630 0.56920 0.67620 0.75660 0.85690  6.493 15.382 23.4*3 25.026 29.86 8 34.377 ' 38.037 41 . 0 8 4 44.356 47.84B 53.081 58.539 64.294 71.5b8 122.  5 .893 10.BS8• 15.445 16.724 20.632 24.04 1 26.928 29,109 31.590 3 4 . 171 37.885 42.031 46.684 52.318 62.443 73.110 90.162  12.21398 6.477B1 3.69791 3.43799 2 . 2 7 599 1.38115 0.97532 0 . 6 6 985 0.47749 0.33741 0.20675 0.13794 0.U9257 0.U5990 • 0.02887 0.01467 0.00450  0.77034 1.03573 1. 18879 1.22335 1.31455 1.38095 1.43021 (.4640? 1 .49955 1.53366 1.57847 1.62357 1 .66917 1.71865 1,79695 1.86398 1 .95502  UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE DRYING 0.00233 0.01364 0.03895 0.05785 0.09705 0.14771 0.19027 0.P4747 0.30896 0.40776 0.48682 0.56203 0.64220 0.76450 0.84507  0.367 0.670 0.B72 0.974 1.084 1 .246 1.339 . 1 .489 1 .646 I .890 2.100 2.312 2.529 2 .768 2.973  0.332 0.-J9S 0.766 0.BB3 0.984 1 . 138 1.225 1.367 1 .515 1 .743 1.942 2 . 139 2.337 2.537 I .693  6.930B1 3.47903 1.9B660 1.53191 1.02615 0.68989 0 . 5 1930 0.367B1 0.26020 0.15178 0.U9774 0.06262 0.03699 0.01360 0.00534  -0.47860 -0.22545 '-0.10459 -0.05416 -0.00689 0.05613 0.08817 f). l3-i7ft 0 . 18044 0.24119 ' 0.28816 0 . 3 3 0 20 0.36870 0.40440 0.43018  UNBEATEN PULP SHEETS WITH 144% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING 0.00053 0.00P80 0.01091 0.03026 0.06234 0.09380 0.13860 0 .17800 0.22030 0.26910 0.34270 0 .41040 0.47620 0.55860 0.63640 0.71650 0.77350  0 .788 1.714 2.761 3.702 4 .297 4.719 5.245 S.704 6.157 6.642 7 .531 8.361 9.186 10.300 11 . 2 7 6 12.254 12.704  0.766 1 .615 2.566 3.49B 4.071 4.477 4.985 5.430 5.869 6.337 7.199 8.00 ) 8.803 9.880 10.812 11.733 12.131  10.73037 6 . b 1700 3.85013 2.30776 1.45259 1.05637 0.73657 0.56187 0.43163 0.32500 0.21630 0 . 14961 0 . 10382 0 . 0 6 396 0.03852 0.02061 0.01244  -0.11560 0.70826 0.41269 0.54387 0.60975 0.65102 0.69768 0.73484 0.76856 0.80190 0.65725 0.90313 0.94465 0.99475 1.03392 1.06940 1.0B389  £  J£*  *r«<ft  ^  UNBEATEN PULP — SOLVENT EXCHANGE DRIED FROM "WATER SUSPENSION 0.00014 0.00082 0.00417 0.01250 0.03580 , 0.05330 0.08420 0.13150 0.17490 0.21300 0.25230 0.29530 0.33900 0.40B20 0.47230 0.53870 • 0.60040 0.66980 0,73860 0.78940 0.93380 0.86120  3.306 B.566 17.334 25.705 33.517 37.137 40.483 . 45.839 49.627 53.245 56.577 60.623 64.619 71.767 79.399 68.118 97.721 110.840 127.300 141.190 155.340 176.890  2.933 ; 6.470 8.906. 14.283 20.300 23.192 25.698 29.543 32.306 35.093 37.569 . 40.678 43.573 48.908 5 5 . 161 62.103 69.669 79.923 93.169 103.398 113.144 127.696  14.85232 9.52454 5.66375 3.62175 2.09123 1.62122 1.15495. 0.77629 0.57337 0.45107 0.35770 0.28062 0.22071 0.15142 0.10613 0.07217 0.03030 0.01732 0.01035 0.00623 0.00302  0.46729 0.61086 0.94967 1.15482  ..'-l.aQ74j_  1.36534 . 1.41327 1.47045 1.50926 1.54522 L.57483_ 1.60936 1.63922 1.68938  ,.  II  11..774913 1 1  1.90267 1.96927 • 2.01451 2.05363 .2.10618  /  BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSK 0.00046 f l . 0 0 164 0.01580 0.02095 0.04838 0.07711 0.13772 0.18834 0.24914 0.31627 0.39086 0.46218 0.52807 0.58551 0.64077 0.70199 0.75434 0.80453 0.84353 0.86639  6.307 ' 11 . 1 ? 0 24.345 26.233 31.996 35.917 41.039 45.104 49.910 54.797 61 . 3 1 0 68.266 76.043 B3.017 92.213 104.002 115.673 128.952 142.421 153.180  5.210 7.228 - 12.688 14.200 18.561 21.343 24.906 27.866 31.378 34.667 39.412 44.765 50.946 56.036 63.IBS 72.354 81.416 90.582 100.077 107.628  0.71687 0.85901 1.10340 1 . 15230  11.13718 7.75710 3.24513 2.81828 1.73003 1.23B57 0.74135 0.52570 0.36429 0.24721. 0.16645 0 . 11235 0.07690 0.0S404 0.03736 0.02361 0.01499 0.00892 0.00546 0.00388  1.32926 1.39631 1.44511 1.49663 1.53991 1.65094 1.70711 1.74846 1.80063 1.85946 1.91071 1 .95704 2.00033. 2.03193  PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE ORIEO FROM WATER SUSPENSION 0.00117 0,00388 0.00844 0.02316 0.03069 0.04776 0.07146 p-(19B?4 0.15332 0.19132 0.23286 0.29776 0.34305 0.40905 .0.47570 0.54167 0.63517 0.73347 0.80994 0.87620  a.Ml 14.185 19.334 25.058 27.263 29.967 32.937 35.349 39.992 42.637 45.799 50.849 54.no 59.983 65.441 72.246 81.472 97.720 .114.725 134.135  5.996 7.563 10.013 14.751 16.565 18.663 20.791 ??.569 26.078 28.054 30.469 34.352 36.669 41.112 45.386 50.698 57.702 69.760 61.449 94.321  .  0.77798 0.87870 1.00057 1.16882 1.21920. 1.27099 1.31768 1.35351 1.41628 1.44799 ...1.48386. 1.53596 1.56430 1.41396  6.59553 5.81157. 4.29899 2.67414 2.28926... 1.74489 1.31317 1.01545 0.6632 3 0.51586 0.40058 0.27682 0.21589 0.15072 0.10411 0.07090  11.65693 .70499 :UJJBU91.84373 1.91354 1.97461  . 0 .. 0 0 13 88 18 25 1 0 0.00838 0.00329  UNBEATEN PULP SHEETS WITH 5.3 X MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING 0.00459 0.01807 0.04795 0.07105 0.10890 0.16510 0.22056 0.27888 0.35509 0.40192 0.47751 0.55006 0.62694 0.68420 0.77313 0.84748  0.650 1.061 1 .326 1.477 1 .623 1.650 2.020 2.231 2.508 2.675 2.998 3.270 • 3.568 3.733 4.070 4.263  0.573 0.957 1.209 1.351 1 . 4 88 1.704 1.663 2.063 2.324 2.481 2.790 3.044 3.319 3.463 3.759 3.889  5.46491 3.03844 1.74034 1.31895 0.92722 0.61191 0.43096 0.30757 0.20220 0.15671 0.1Q3Q5. 0.06739 0.04112 0.02716 0.01249 0.0,0517  -0.24169 •0.01894 0,08231 0.13070 O. 17?A4 0.23137 0.27026 0.31459 . 0.36626 0.39457 ... 0.44555 0.48341. 0.52103j 0.53946 0.57502 0.58982 :  UNBEATEN PULP SHEETS WITH 53jS% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING 0.00017 0.00057 0.00200 0.00635 0.01316 0.02937 0.04653 0.06670 0.08330 0.10020 0.11640 0.16100 0.19710 0.23130 0.Z8210 0.37520 0.44330 0.53970 0.62830 0.69720 0.76350 0.820B0 , 0.87630  2.629 5.144 6.850 12.909 16.409 19.919 22.398 23.613 25.225 26.457 27.558 30.275 32.377 34.380 37.621 44.013 49.313 58.151 68.694 78.143 89.305 99.821 1 1 1 . 0 3 9 .. ...  2.379 4.326 6.231 • 7.035 10.026 12.785 14.802 15.779 - 16.898 17.858 18.757 20.864 22.531 24.122 26.751 31.853 36.259 43.745' 52.582 60.378 69.585 77.247 84.338.  14.20952 10.52435 • 7.28444 4.82780 2.34732 1.72657 1.38266 1.16500 0.99827 0.87244_ 0.62913 0.49747 0.40427 0.30206 0 . 18125 0.12482 0.07174 0.04074 0.02454 . O.Ql3>3 0.00736 . 9^ft012___  0.37638. 0.63604 0.79436 .0.64726  -  .  -  '  1 . 1 0 6 70 j 1.1703l! 1.19807 1.22782 1.25184 U 21316, 1.31939 1.33278 1.36241 1.42733 1.50315 1.55942 1.64093 | 1.72084 1.76088 1 1.64251 l;88788 1  -243-  TABLE I. CONTINUED  CYLINDRICAL PORE MODEL UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  p p.  0.00014 0 . 0 0 0 82 0.00417 0.01250 0.03580 0.05330 0.08420 0. 1 3 1 5 0 0.17490 0.21300 0.25230 0.29530 0.33900 0.40820 0.47230 0.53870 .0 . 6 0 0 4 0 0.66980 0 .73860 0.7 8 9 4 0 0 .83380 0.88120  ads. mts(S.TPj/9 v  3.306 8 .566 17.334 2 5.70 5 33.517 37.137 40.983 45.839 49.627 53.245 5 6 . 5 77 60.62 3 64.619 71 .767 79.399 . 88.118 97.721 110.840 12 7 . 3 0 0 141.190 155.3 40 1 7 6 . 8 90  2.970 6 .679 9.749 15.425 21.621 24.587' 27.406 3 1 . 172 34.03 8 36.908 39.470 42 .672 45.678 51.194 57.585 64.705 72 . 4 7 4 83.015 96.582 1 0 7 . 177 117.364 132.615  14.85232 9.52454 5.66375 3.62175 2.09125 1.62122 1.15495 0.77629 0.57337 0.45107 0.35770 0.28 06 2 0.2207 1 0.15142 0.10613 0.07217 0.0 4 9 0 9 0.0 30 30 0.01732 0.01055 0.00623 0.00302  0.47278 0.82473 0.98894 1.18823 1.33488 1.39070 1.43 78 5 1.49377 1. 5 3 1 9 6 1.56713 1.59626 1,63015 1.65970 1.70922 1.76031 1 , 8 1 0 94 1.86018 1.91916 1 .98489 2.03010 2.06953 2 . 1 2 2 59  -244TABLE2:  B.E.T. AND DUBININ (OR KAGANER) DATA  UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  5.634 2.476 2.098  0.0T09 0.0933 0.1187  0.001954 0.002470 0.003033  1.321 1.061 0.857  0.1621  0.004003 0.005151  0.624 0.444  0.006563  0.310 0.235 0.169 0.105  0.2155 0.2777  1.154 1.487  .  ,  1.525 1.592 1.620 1.6471  0.07B6 0.0920 0.1279  0.002475 0.00269B 0.003521  1.684' 1.727  0.1600 0.2374  0.004146 0.005832  1.768 1.604 1.843 1.901  3.173 2.111 2.036 1.217 1.074 0.798 0.634 0.390 0.262 0.134 0.119 0.093  1.160 1.359 1.367 1.539 1.575 1.619 1.662 .1.727 1.783 1.871 1.888 ,1.921  0.0877 0.0989 n.?D4l 0.2449 0.2999  0.002485 0.002653 0.0O474A 0.005453 0.006489  4.650 3.643 2.032 1.996 1.117 1.010 0.474 0.373  0*274 0.199 0.154 0.107 0.069  0.933 1.143 1.419 1.439, 1.588 1.617 1.732 1.774 1.820 1.870 1.912 1.969 2.038  UNBEATEN PULP —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  0.0842 0.1315 0.1749 0.2130 0.2523 0.2953  n.'nm *i 6 0.002243 0.003303 0.004271 0.009063 0.005964 0.006912  14.852 9.525 5.664 3.622 2.091 1 .fc?l 1.155 0.776 0.573 0.451 0.358 0.281 0.221 0.151 0.106 0.072  0.519 0.933 1.239 1.410 1.525 1 .S70 1.613 1.661. 1.696 1.726 1.753 1.783 1.810 1.856 1.900 1.445  0.0742 0.1 ?*s 0.1533 0.1976 0.2314  0.002296 0.003319 0.003874 0.004792 0.005432  5.553 3.648 2.550 1.734 1.276 0.81 9 0.662 0.496 0.404 0.267 0.209 0.164 0.119 0.087  0.879 1.127 1.329. 1.459 1.543 1.632 1.670 1.711 1.744 1.795 1.830 1.865 1.908 1.949  3.265 2.061 1.279 0.751 0.572  1.148 1.377 1.536 1.621 1.664  0.317 0.256 0.170 6.122 0.068  1.744 1. 774 1.829 1.872 1.915  5.649 3.469 1.999 1.061 0.870 0.539 0.372 0.290 0.215 0.168 0.124 0.092 0.073  0.716 1.132 1.362 1.525 1.564 1.637 1.691 1.723 1.765 1.801 1.837 1.874 1.905'  5.750 4.185 2.645 1.720 1.096 0.917 0.700 0.52B 0.373 0.249 0.194 0.193 0.137 0.103  0.764 1.000 1.255 1.406 1.514 1.547 1.588 1.627 1.670 1.720 1.752 1.752 1.793 1.B28  3.503 2.327 1.443 0.916 0.739  1.041 1.258 1.413 1.519 1.558  0.438 ~ 0.368 0.282 0.231 0.195 0.166 0.116 0.078  1.636 1.662 1.693 1.722 1.745 1.767 1.813 1.859  PULP BEATEN I MINUTE —SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  0.0504 0.0785 0.1286 0.1717 0.2222 0.2818  0.001533 0.002216 0.003413 0.004404 0.005588 0.007009  8.849 6.034 2.951 1.684 1.221 0.794 0.586 0.427 0.303 0.216 0.158 0.111 0.077  0.954 1. 196 1.443 1.539 1.585 1.636 1.673 1.708 1.748 1.789 1.827 1.670 1.909  0.0740 0.1359 0.1752 0.27117 0.2737  0.002325 0.003764 0.004601 0.00578R 0.006796  0.0510 0.1026 0.1750 .0*2096  0.001 0.002 0.004 0.00A  836 919 338 32.5_  4.244 2.624 1.670 0.976 0.573 0.4^L_ 0.265 0.189 0.075  0.951 1.231 1.467. . 1.593! 1.689 • 731 1.607 1.861 1.939 2.002  3.314 1.527 0.959 0.725 0.593 0.399 0.296 0.201 0.136 0.084  1.112 1.450 1.556 1.611: 1.650 1.710 1.759 1.813 1.873 1.947  0.113  PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  0.0771 0.1377 0.1883 0.2491  0.002326 0.003892 0.005145 0.006648  11 .137 7.757 3.245 2.818 1.730 1 .239 0.741 0.526 0.364 0.247 0.166 0.112 0.077  0.805 1.046 1.386 1.419 1.505 1.1SS 1.613. 1.654 1.698 1.739 1.788 1.834 1.881  0.0933 0.1167 n.iRhs 0.2457 0.2891  0.003073 0.003603 0.005217 0.006631 0.007686  PULP BEATEN S MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  0.L029 0.1519 0.2037 0.2625  o-nOPOB? 0.003016 0.004360 0.005767 0.007439  12.214 6.47B 3.698 3.438 2.276 1 .381 0.975 0.670 0.477 0.337 0.207 0.138 0.093  0.812 1.187. 1.371 1.398 1.475 1.580 1.614 1.647 1.6B0 1.725 1.767 l.BOB  O.0898 0.1102 0.1456 0.1877 0.2451  0.003022 0.063516 0.004402 0.005453 0.006940  PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  0.0715 0.0982 0.1533 0.1913 0.2329 n.?Q76  0.002337 0.003082 0.00452 6 0.005549 0.006628 n.nnA^3«  B.596 5.812 4.299 2.674 2.289 1.745 1.313 1.015 0.663 0.516 0.401 0.277 0.216 0.151 0.104 0.071  0.925 1.152 1.286 1.399 1.436 l.*77 1.518 1.548 1.602 1.630 1.661 1.706 1.733 1.776 1.816 1.859,  0.0629 0.002592 0.11D4 0.003759 0.1381 0.00443* 0.18S6 0.005671 .0.2177 0.006432 0.2476 0.007168 0.2947 0.008464  0.0581 0.1049 0.1408 0.1699 0.2335 0.2860  0  002188 003253 004016 004584 0 LQ05942 0.006972 0 0 0  -245TABLE 2. CONTINUED • VACUUM ORIEP UNBEATEN PULP SHEETS NITROGEN  _P  P  P.  7^  0.0721 0.1149  1.0939 1.3253  0.1746 B.J131  1.9954 2.2B94  0.2970  2.0931  0.0994 0.1409 0.1655 .0.2483  1.8698 1.8028 1.9257 2.7304  0.0882 0.1224 0.1587 0.2091  1.8591 1.5071 2.2192 2.2793 2.6457  0.0878 0.1352 0.2052 0.2516  1.5785 1.6991 2.2450 2.7329 2-8973  UNBEATEN PULP SHEETS—VACUUM DRIED PRIOR TO SOLVENT EXCHANGE DRYING P  0.0578 0.0971 n.t*77 0.1903 0.2475  0.06304 0.09916 n.H9l 0.1735 0.2209  6.931 3.479 1.987 1.532 1.026 (1.690 0.519 0.368 0.260 0.152 0.098  -0.433 -0.174 -0.059 -0.011 0.033 0.096 0.127 0.173 . 0.216 0.276 0.322  UNBEATEN PULP SHEETS WITH 5 . 3 % MOISTURE  0.0710 0.1089 0.1651 0.2206 0.2789  0.03178 0.07530 0.1069 0.1401 0.1733  9.465 3.038 1 .740 1.319 0.927 0.612 0.431 0.308 0.202 0.157 0.103  -0.187 0.026 0.123 0.169 0.210 0.267 0.305 0.34B 0.399 0.427 0.477  0.0741 0.0968 0.1427 0.1972 ' 0.2586 0.2967  0.09108 0.1071 0.1415 0.1816 0.2278 0.2509  3.030 2.016 1.277 1.029 0.715 0.497 0.345 0.279 0.203 0.135 0.093  TO SOLVENT EXCHANGE DRYING  0.0788 0.1004 0.1705 ft,7W\?  0.06075 0.07082 0.1071 Q l^5fl P  3.235 2.426 1.218 0.997 0.590 0,. 4Q7 0.239 0.165 0.131 0.100  UNBEATEN PULP SHEETS WITH 14.4% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING  0,0623 0.0938 0.1386 0.17B0 0.2203 0.2691  0.01347 0.02193 0.03068 0.03796 0.04369 0.05543  10.730 6.517 3.850 2.306 1.453 .056 0.737 0.562 0.432 0.325 0.216 .150 0.104  0.568 0.633 ,0.674 .0.720 0.756 0.784 0.822 0.677 0.922 0.963  UNBEATEN PULP SHEETS WITH 33^6% MOISTURE PRIOR TO SOLVENT EXCHANGE DRYING  0.0667 0.0833 0.1002 0.1164 n.lMfl 0.1971 0.2313 0.2821  0.003001 0.003602 0.004209 0.004760 0.006438 0.007582 0.008752 0.0104S  14.210 10.524 7.284 4.82B 3.537 ?.147 1.727 1.383 1.165 0.998 0.872 O.A29 0.497 0.404 0.302 O.ljl 0.125 0.072  0.420 0.711 0.947 1.111 1.215 1.299 1.350 1.377 1.402 1.423 1.440 1.481 1.510 1.536 1.575 1.644 1.693 1.765  -0,376 -0.1B4 -0.056 0.0 . 0.070 0.131 0.183 0.226 0.269 0.319 0.366  -0.272 -0.065 0.144 0.196 0.283 Q,343 0.418 0.470 0.502 0.538  *. 0.0654 0.1237 0 . 1 5 76 0.2388 0.2818  0.08266 0.1238 0.1423 0.1947 0.2173  2.259 1.402 0.824 0.644 0.387 0.303 0.241 0.173 0.119 0.083  -0.239 -0.072 0.057 0.118 0.207 0.257 0.294 0.347 0,403 0.447  APPENDIX H  t-PLOT DATA UNBEATEN PULJ>—SCtytVfEXCMA«ISE  JtiL  DRIED F R O ! WATER SUSPENSION;  n.nn*.9*n  l*-74?  ; x ! .; * > l 0.\77  0.026690  30.710  0.694  0.035600  33.514  0.757  0.854 I 0.884  -  sra ;  * :  - • } 0.370  J  UNBEATEN PULP—SOLVENT EXCHANGE OWED FROM WATgSUSPSISlOW i ; * - . • 0.000140  1.1(16  0.000820  8.566  0.193 .  0.140  0.004170  17.334  0.391  0.564j  O-HA?  0.9A5  n.n*->*nn  »5.7A5  P-*79  Q TJL«  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  0.215500  53.327  1.204  1.141 ".' * \  0.277700  58.579  1.323  1.310  • n.*??son  63.635  1 .437  1.393  0.387800  69.692  1.574  1.443_  0.473600  79.570  1.797  40.983  (1.974  1.010  0.131300  45.839  1.033'  1.091  0.174900  49.627  1.118  1.160  53.745  l.?00  1.715  0.252300  56.577  1.273  1.273  1.625  0.295300  60.623  1.366  1.336  64.619  1.4*56.  1.409  ftA.R41  1 .461  1.727  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  n.77nno  ll&.TIft  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  PULP BEATEN 3 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  •  11.966  Il  15.695  0.714 0.376  0.019144  27.720~ ^  6.664  10.003496  j  ^  0.179  0.498J.  1 0.815  n.n*oi7fl  1 * . AIT  ft.^7 9  '0.076490  38.430  0.920  0.128575  43.226  1.035  0.222156  51.107  1.224  1.229  0.281775  55.970  1.341  1.316  n.i4?Aft5  - t.\ .511  1 .47*  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  0.979  r  0.434000  t\. 51770ft  In.ftrtiAAO  (1.(175  14.A47  1  j' W  !  0.093300  1.219  PULP BEATEN I MMUTE—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  . . p i  I  0.833800  155.340  3.501  {2.825  0.881700  176.890  3-487  3.294  PULP BEATEN 9 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  ft.1716ft?  1.000 (  1.066  1 .177  PULP BEATEN 10 MINUTES—SOLVENT EXCHANGE DRIED FROM WATER SUSPENSION  0.165  (l.Ofll  n.(inni?o  6.441  O. 179  O.OS6  " 0,,pQil70  8.41 1  0.2B1  0 . 196  0.288  0.266  0.002650  15.382  0.425  0.426  0.003884  14.185  0.474  0.538  24.345  0.630  0.798  0.011940 -  23.493  0.649  0.758  0.008445  19.334  0.647  0.754  0.0?O9 5?  76.733  D.679  0.823  ft.013990  7S.076  ft.691  0.7ft?  .0.073159  25..05 8  Il*fl2fl  0.837  0.048383  31.996  0.628  0.919  0.031000  29.868  0.825  0.870  0.030688  27.263  0.912  0.B68  6.1B7 0.001640  11.120  0.015797 ,  -  0.077106  35.917  0.929  0.997  0.066800  34.377  0.949  0.973  0.137716.  41 .039  1.067  1.104  fl.lft?90ft  18.017  1.050  1.046  0.047759  0.188343  45.104  1.167  1.179  0.151900  41 .084  1.134  1.127  . 0.098244  35.344  1.162  1.037  0.249137  49.410  1 .291  1.268  0.203700  44.356  1.225  1.202  0.153325  39.992  1.338  1.129  • 0.767S00  47.848  l .17 1  1.28R  0.191371  4? .63 7  1.476  1.184.  0.351000  53.081  1 .466  1.431  0.232857  45.799  1.532  .1.244 1.339  _m7.l46Q J  '  29.967  l.OOZ  3?..437  1-11)7  0.9la .  0.48 6,  0.318773  54.747  1 .418  . 1.378  0.390860  61.310  1.586  1.499  0.462181  68.266  1.766  1.608  0.425200  58.539  1.616  1.554.  0.297760  50.B49  1.701  0.578069  76.043  1.967  1.718  (1.44610n  64.794  1 .775  1.65R  0.343055  54.110  1.610  1.416  0.585515  83.017  2.146  1.846  0.569200  71.558  1.976  1.812  0.409048  59.983  2.006  1.532  0.640772  92.213  2.386  1.986  (1.701943  104.00?  7.69 1  7.166  0.754343  115.673  2.993  2.344  0.804528  128.952  3.336  2.626  O.84157*  147.471  3.665  2.898  0.666387  153.180  3.963  3.117  0.676200  85.129  2.350  2.089  0.475702  65.441  2.189  1.628  O. 756600  98.1?0  7.709  2.355  0.541673  72.246  2.416  1.749  0.856900  122.192  3.374  3.016  0.635172  81.972  2.742  j 1.970  0.733475  97.720  3.266  P.60993B ,  114.72S  3_.B3J  0.876200  134.135  4.486  2.268 2 ^ 6 1 . 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 DRIED PRIOR TO S O L V E N T E X C H A N G E DRYING p p.  •  U N B E A T E N PULP S H E E T S WITH 5 . 3 % MOISTURE PRIOR T O S O L V E N T EXCHANGE ORYING P  STO«y  ' P.  V  !  '• 0 . 6 O 1  0.002330  0.367  0.309  0.361  0.004595  0.650  0.013639  0.670  0.564  0.778  0.018067  1.061  0.633  0.811'  0.036952  0.872  0.735  0.893  0.047949  1.326  0.791  0.918  0 .97*  n.n?l  0.447  0.071047  1.477  0.881  0.985  0.097053  1.084  0.913  1.035  0.108904  1.623  0.968  1.055  0.14770B  1.246  1.050  1.121  0.165103  1.B50  1.103  1.146  n . l Q(i77*  l.V*9  l . i?ft  1 .187  • 0.77055ft  ?.ft?0  1.204  1.226  0.24747*  1.489  1.254  1.266  0.278877  2.231  1.330  1.312  0.308961  1.646  1.387  1.359  0.355090  2.508  1.496  1.439  0.*07761  1 .890  1.59?  1.530  ft.&fl141A  ?.h7«»  1 .194  i . w i  0.486B24  2.100  1.769  1.644  0.477509  2.998  1.788  1.631  0.562026  2.312  1.948  1.796  0.550056  3.270  1.950  1.771  0.A47705  2.579  2. 131  1.990  0.626941  3.568  7.17ft  1.947  0.764497  2.76B  2.332  2.393  0.684204  3.733  2.226  ' 2.112  0.845067  2.973  2.505  2.909  0.773127  4.070  2.427  2.438  0.847482  4.263  <t*42  2t?28  UNBEATEN PULP SHEETS WITH  '  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 T O S O L V E N T E X C H A N G E D R Y I N G 0.030  0.000530  0 7RH  0  0 09?  0.000170  2.629  0.093  0.002800  1.71*  0.335  0.420  0.000570  5.144  0.183  0.099  0.010910  2.761  0.540  0.743  0.002000  8.850  0.314  "0.317  O.O307AO  -\ 7 0 ?  0 775  0 Rf>7  rt.oof.^5n  17.909  0.459  0.709  0.062340  4.297  0 .841  0.960  0.013160  16.409  0.583  0.773  0.093800  4.719  0.924  1.029  0.029370  19.919  0.708  0.864  0.138600  5.745  1  U0fl6_  0.0*R<*™  77.198  0.79fc  fl.4?0  0.178000  5.704  1 . 116  1.164  0.066700  23.813  0.846  0.973  0.220300  6.157  1 .205  1.226  0.083300  25.225  0.896  1.008  0.269100  6.642  1 .300  1.297  n.iofl?no  ?*.-AS 7  A.94D  1.041  0.342700  7.531  1 .474  1.415  0.116400  27.558  0.979  1.066  0.410400  8.361  1 .637  1.534  0.161000  30.275  1.076  1 . 140  0.476200  9.1B6  1 .798  1 629  0.147100  17.377  Itl 50  1.192  0.558600  10.300  2.016  1.789  0.231300  34.380  1.221  1.242  0.636400  11 . 2 7 6  2.207  1.974 '  0.282100  37.621  1 .337  1.316  n.71flsnn  1?  7 199  ? ?1B  n.V7«i?nn  44.013  1 .564  1.472  0.773500  12.704  2.487  2.4*0  0.443300  49.313  1.752  1.581  6.539700  58.151  2.066  1.744  n.fi?mno  AB.A94  ?.*41  1.951  0.697200  78.143  2.776  2.151  0.763500  89.305  3.173  2.388  n.n?nnno  99.B71  3.546  7.734  0.876300  111 . 0 3 9  3.945  3.233  0?7  -248APPENDIX H T a b l e 2:  Comparison o f " t " - P l o t Values Using t h e D i f f e r e n t "Standard" Isotherms  U n b e a t e n S o l v e n t E x c h a n g e D r i e d Prom S u s p e n s i o n Standard Isotherm v/v * m  *  Payne & Sing (17D  Lippens et a l (110)  Sample  Used Pierc< (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  calculated  f r o m B.E.T. e q u a t i o n  APPENDIX I S t u d y 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 Volumetric Apparatus  This study estimated the 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 w o u l d  a l w a y s 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 . c a l c u l a t e d through from primary d a t a . calculations  One r u n was  The r e s u l t s o f t h e s e  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.  Atmospheric  ± 0.010  cm.  Pressure  Temperature  ± 0.2 °P  Dead Volume  ± 0.2 JS  Sample Weight  ± 0.2 %  Results of Error  Calculations  Calculated Variable  High  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 P o r e Volume (mis.(S.T.P.)/g.)  170.1  168.7  167.6  Cumulative Pore Area (sq.m./g.)  115-8  114.9  114.3  213  212  211  25-16  25-15  25-14  50.9  50.1  49.1  Large Wall S e p a r a t i o n  ( a ) M o s t Common P o r e S i z e (ft S e p a r a t i o n ) Uncorrected Dubinin Plot Intercept (mis.(S.T.P.)/g.)  -250APPENDIX 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 t o 78  °K.  The  i n Barron  properties  f o l l o w i n g data  o f A r g o n and  i s given  (164)  f o r the  Oxygen.  Temperature • ° R.  Argon D e n s i t y l b ./cu. f t . m  Heats of V a p o u r i z a t i o n B.t.u./lb . m Oxygen Argon  220  71.4  53.3  73.2  200  77.1  59.6  80.6  190  79-8  62.4  180  82.42  65.0  170  84.66  67.1  160  86.91  69.1  15.7.1  87.56  69-5  155  88.03  69.8  87.4 92.2  96.6  140 A p l o t of d e n s i t y versus linear plot.  temperature revealed  was e x t r a p o l a t e d  This  t o y i e l d a d e n s i t y o f 90.65 l b Heat o f V a p o r i z a t i o n : A p l o t o f t h e ization  of argon versus  ization  of oxygen i s l i n e a r  T h i s was  extrapolated  an e s t i m a t e 140.3 was Surface  ,  °R. 72.6  value  B.t.u./lb  (140.3  (1.452  l o g of the heat of  the  g./cc.). vapour-  l o g of the heat of over the  on t h e  obtained  vapour-  r a n g e 160  oxygen data  to  220  determine  from t h i s  at  extrapolation  .  extrapolated  dynes/cm. was (166).  ./cu.ft.  °K  of the heat of v a p o u r i z a t i o n of argon The  T e n s i o n : The  t o 78  a  • surface  tension value,  14.9  t a k e n f r o m t h e w o r k o f Emmett a n d , C i n e s , i  °R,  APPENDIX K Comparison o f R e s u l t s from D u p l i c a t e Sample  Cumulative Pore V o l .  Samples  C u m u l a t i v e B.E.T. Dubinin Intercept Pore Area Area mis.(S.T.P.)/g. sq.m./g. sq.m./g. U n c o r r e c t e d Corrected  N i t r o g e n on U n b e a t e n P u l p - S o l v e n t E x c h a n g e  Kaganer Surface Area sq.m./g.  "t"-plot Surface Area sq.m./g.  Dried  Isotherm 1  150.3* 201.4**  122.3* 218.5**  193-0  49  33  214  262  Isotherm 2  159-1* 210.6**  124.9* 221.1**  193-4  54  34  236  261  N i t r o g e n on P u l p B e a t e n 10 M i n u t e s - S o l v e n t E x c h a n g e Isotherm 1  117-1* 151.9**  86.5* 150.7**  Isotherm 2  120.6* 153-5**  84.9* 143.7**  A r g o n on U n b e a t e n P u l p - S o l v e n t E x c h a n g e  Dried  Dried  Isotherm 1  170.1  55  206  Isotherm 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 M o d e l Assumed ** C y l i n d r i c a l  P o r e M o d e l Assumed  PORE ANALYSIS ON DUPLICATE SOLVENT EXCHANGE PARALLEL ISOTHERM  JL  SIDED FISSURE  PULP  I.  ads.  v  wall separation  pore area  sum of pore area sq.rryg.  0. 900 199.400 0. 850 181.000 0. 800 164.100 0. 75 0 ._.149.200 0. 700 138.400 0. 650 128.700 C. 600 120.800 0. 550 114.100 0. 500 105.500 0. 480 90.200 0. 460 81 .400 0. 440 76.900 • 0. 400 71.500 0. 350 66.000  0.900 0.850 0 .800 0.750 0 .700 0.650 0 .600 0.550 0 .500 0.480 0 .460 0.440 0 .400 0.350  UNBEATEN  MODEL  P .  ISOTHERM  DRIED  pore sum of pore vol. & pore volume volume £ pore size mUSTPj/g. ml(S.T.P>g.  96. 48 3 69. 781 55. 128 4 5 . 721 39.097 34. 135 30. 248 27. 09 4 25. 164 24. 184 23. 263 21. 99 3 20. 248  7. 513 9. 230 9. 981 8. 294 8.477 7. 551 6. 916 10. 327 22. 26 9 12. 686 6. 050 6. 542 6. 503  7.513 16.743 26.724 35.018 43.495 51.045 57.962 68.288 90.558 103.244 109.294 115. 836 122.338  2 3 . 38 3 20.777 17. 750 12. 233 10. 691 8. 314 6. 748 9. 025 18. 077 9. 897 4. 540 4. 641 4. 247  2 3.383 0.663000 44.159 1.145679 61 .909 1.588832 "74.142 1 .600437 84.833 1.907590 93.147 1.925174 1.952561 99.895 108.921 3.165624 126.997 17.892715 136.895 10.433136 141.435 5.079371 146.075 2.818710 2.304694 150.323  96.483 69.781 55.128 45.721 39.097 34.135 30 .248 27.094 2 5.164 24.184 23 .263 21 .993 20.248  9.228 10.289 10.447 10.060 8 .908 7.605 6.747 7.494 15.445 16 .970 6 .863 8.062 6 .800  9.228 19.516 29.964 40.024 48.932 56.536 63.283 70.777 86.222 103. 192 110.055 118.118 124.918  28.720 23.160 18.579 14.837 11.235 8.374 6. 583 6. 550 12.537 13.239 5. 150 5. 720 4.441  0 .814337 28.720 1.277082 51.880 70.459 1 .663061 85.296 1.941166 96.530 2.004613 104.904 1.938977 1 .904794 111.487 118.037 2.297228 130.574 12 .409334 143.813 13.956253 5.762108 148.963 154.683 3.473923 159.125 2.410062  2. 207.300 184.700 165.800 150.100 137.100 126.800 118.700 112.000 105.300 94.500 83.000 78.000 71.700 66 .000  PORE ANALYSIS ON DUPLICATE SOLVENT EXCHANGE DRIED UNBEATEN PULP CYLINDRICAL PORE MODEL ISOTHERM I. ads.  v  P« 0.900 C. 850 0.800 0.750 0.700 0.650 c. 600 0. 550 0. 500 0. 480 0. 460 0. 440 0. 400 0. 350  mls(ST.P)/g 199.400 181.000 164.100 149.POO 138.400 128.700 120.800 114.100 105.500 90.200 81.400 76.900 71.500 66.000  diam of pore  A  pore area sq.rryg.  sum of pore area sq.rryg.  pore volume mLSTP/g  85.838 60.507 46.774 38.052 31.972 27.462 23.961 21.147 19.435 18.573 17.765 16.657 15.145  9.206 12.312 14.373 12.708 13.864 12.97 8 12.436 20.521 49.190 27.653 12. 132 11.163 9.915  9. 206 _21.518 35.891 48.599 62.463 7 5.441 87.877 108.398 157.588 185.241 197.373 208.536 218.451  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  118.700 112.000 105 .300 94.500 83 .000 7 8.000 71.700 66 .000  27.462 23 .961 21 .147 19.435 18.573 17.765 16.657 15.145  12 .955 11.968 14.233 33 .825 37.925 14.213 15.237 10.778  82.964 94.932 109. 165 142.990 180.915 195.128 210.365 2 21.142  11.476 9.250 9.709 21.207 22.722 8. 145 8. 187 5.265  25.492 24.030 21.687 15.599 14.298 11.497 9.612 13.998 30.840 .16. 568 6.953 5.998 4. 844  sum of pore vol. A pore volume ml.(S.T.^gAP° re  25.492 49.522 71.209 86.808 101.106 112.603 122.215 136.213 167.053 183.621 190.573 196.571 201.415  0.758829 1.408004 2.085208 2.214420 2.795108 2.943970 3. 103894 5.530292 34.608826 19.874390 8.884956 4.184652 3.045551  31.311 58.077 80.735 99.725  0.932040 1.568292 2.178630 2.695895  ISOTHERM 2 0 .900 0.850 0 .800 0.750 0 .700 0.650 0 .600 0.550 0 .500 0.480 0 .460 0.440 0 .400 0.350  126.156 2.938665 135.406 2 .987172 145.115 3.835658 166.322 23.798172 189.044 27.257278 197.189 10 .408657 205.376 5.711718 210.642 3 .310573  l.  ro VJl OJ  l  PORE ANALYSIS ON DULICATE SOLVENT EXCHANGE DRIED PULP BEATEN 10 MINUTES PARALLEL SIDED FISSURE MODEL ISOTHERM I. ads. mts(SXR)/9 v  wall separation  A  0,900 0 .850 0.800 0.750 0.700 0 .650  159.000 136.000 122.000 111.000 102.000 96.000  96.483 69 .781 5 5 . 128 45.721 39.097  0 .550 0.500 0.480 0.460 0 .440 0.400 0.350  85 .500 80 .500 76.000 66.000 63.000 59.000 55.000  ISOTHERM 0.900 0 .850 '0.800 0 .750 0.700 0 .650 0.600 0 .550 0.500 0 .480 0.460 0 .440 0.400 0 .350  pore area sq-rryg.  sum of pore area sq.m./g.  pore volume  sum of pore vol. i=J-  I u m e  30.248 27.094 2 5 . 164 24.184 23.263 2 1.993 2 0.24 8  9.39 1 7.517 7.200 6.848 4.938 5 .644 4.422 5 .631 6. 166 14.967 3.986 4.950 4.811  9.391 16.908 24.108 30.956 35.894 41.538 4 5.9 60 51.59 1 57.757 72.724 76.710 81.660 86.471  29.228 16.921 12.804 10.100 6. 228 6.215 4. 3 1 4 4.921 5. 0 0 5 11.676 2. 991 3. 512 3. 142  29, 2 2 8 46 , 149 58, 953 69, 0 5 3 75, 281 81 ,4 9 6 85 .810 90.732 95.737 107.413 110.404 113.916 117.058  0.828750 0 .933056 1.146091 1 .321426 1.1 1 1 2 9 5 1 .439112 1 .248314 1 .726151 4.954384 12 . 3 0 8 5 0 4 3.346241 2 .133071 1 .705007  96 .483 69.781 55 .128 45.721 39.097 34.135 30.248 27.094 25.164 24.184 23.263 21 .993 20 .248  10.412 8 .773 7.613 6.414 5.757 5 .321 4.590 4. 136 7.206 12 .586 3.985 5.119 2 .957  10.412 19.185 26.798 33.212 38.969 44.291 48.88 1 53.017 60.223 72.809 76.794 81.913 84.870  32.405 19.749 13.539 9.459 7.261 5.859 4.479 3.615 5.849 9.819 2.990 3.632 1.931  32.405 52.154 65.693 75.152 82.413 88.273 92.752 96.367 102.216 112.035 115.025 118.657 120.588  0.918832 1.088985 1.211926 1 .237582 1.295621 1 .356727 1.295913 1.267979 5.789632 10 .350 646 3.345369 2 .205873 1 .047867  2.  160.000 134.500 118.200 106 .500 97.900 91 .000 85 .200 80 .500 76.500 71.300 62 .800 59.800 55.700 52 .700  —  PORE ANALYSIS ON PULICATE SOLVENT EXCHANGE DRIED PULP BEATEN 10 MINUTES CYLINDRICAL PORE MODEL ISOTHERM I. sum of pore m of diam. of pore ods. pore area volume pore vol. & P ° pore area mlslSXRVg sq.rryg. mLSTP/g m ! ( S j i ^ & P sqm/o, S U  v  o r e  0 .900 0.850 0 .800 0.750 0.700 0.650 0 .600 0.550 0 .500 0.480 0.460 0.440 0.400 0.3 50  159.000 136.000 122.000 111.000 102.000 96.000 90.000 85.500 80.500 76.000 66.000 63.000 59.000 55.000  re s l z e  85 .838 60.507 46.774 3 8.05 2 31.972 27.462 23.961 21. 147 19 .435 18.573 17.765 16.657 15.145  11.508 9.986 10.306 10.486 7.883 9 .696 7.781 10.834 13.187 33.906 8.027 9 .06 3 7 .996  11.508 21.494 31.800 42.286 50.169 59.864 67.645 78.479 91.665 125.572 133.599 142.662 150.658  31.865 19.492 15.550 12.871 8. 130 8.589 6.014 7. 390 8. 267 20.314 4. 600 4. 870 3. 907  0 .948537 31 .865 51.357 1.142076 1 .495132 66 .907 1.827189 79.777 1 .589287 87 .907 2.199409 96.497 102.510 1 .942039 2 .919578 109.901 118.168 9.277696 138.482 24.368973 5 .878546 143.082 147.952 3.397292 2 .456254 151.859  85 .838 60.507 46.774 38.052 31.972 27.462 23.961 21.147 19.435 18.573 17.765 16.657 15.145  12 .759 11 .662 10.877 9.749 9.268 9.029 8.076 7.520 15 .561 28 .349 8. 107 9 .666 3.062  12.759 . 24.421 35.298 45.047 54.315 63.344 71.420 78.940 94.501 122.850 130.957 140.623 143.686  35. 328 22. 762 16. 411 11. 967 9. 559 7 .999 6. 242 5. 130 9. 756 16. 985 4. 646 5. 194 1. 49 6  35.328 1.051638 58.091 1 .333710 74.502 1.577969 86.469 1 .698815 96.028 1.868598 104.026 2 .048231 110.268 2.015640 115.398 2 .026561 125.154 10.948153 142.139 20 .375061 146.785 5.937168 151.979 3 .623425 0.940693 153.475  ISOTHERM 2. 0.900 0 .850 0.800 0 .750 0.700 0.650 0.600 0 .550 0.500 0 .480 0 .460 0 .440 0.400 0 .350  160.000 134.500 118.200 106.500 97.900 91.000 85 .200 80 .500 76.500 71 .300 62 .800 59 .800 55.700 52.700  I ro  I  

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