Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Studies on the crystallinity of wood cellulose fibres by X-ray methods. Lee, Chi-Long 1960

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1960_A6 L3 S8.pdf [ 5.37MB ]
Metadata
JSON: 831-1.0105951.json
JSON-LD: 831-1.0105951-ld.json
RDF/XML (Pretty): 831-1.0105951-rdf.xml
RDF/JSON: 831-1.0105951-rdf.json
Turtle: 831-1.0105951-turtle.txt
N-Triples: 831-1.0105951-rdf-ntriples.txt
Original Record: 831-1.0105951-source.json
Full Text
831-1.0105951-fulltext.txt
Citation
831-1.0105951.ris

Full Text

STUDIES ON THE CRYSTALLINITY OF WOOD CELLULOSE FIBRES BY X-RAY METHODS by CHI-LONG LEE B.S.F. Taiwan Prov. C o l l . o f Agr., China, 1955  A THESIS SUBMITTED I F PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF FORESTRY i n the Faculty of Forestry  We accept t h i s t h e s i s as conforming required  t o the  standard  THE UNIVERSITY OF BRITISH COLUMBIA April,  i960  In p r e s e n t i n g the  this  thesis i n partial  r e q u i r e m e n t s f o r an advanced degree a t t h e U n i v e r s i t y  of B r i t i s h Columbia, I agree that it  fulfilment of  freely  agree t h a t for  the Library  a v a i l a b l e f o r r e f e r e n c e and s t u d y . permission f o r extensive  make  I further  copying of t h i s  thesis  s c h o l a r l y p u r p o s e s . m a y be g r a n t e d by t h e Head o f my  D e p a r t m e n t o r by h i s r e p r e s e n t a t i v e s .  I t i s understood  that  copying or p u b l i c a t i o n of t h i s  gain  s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n  Department o f  Forestry  The U n i v e r s i t y o f B r i t i s h Vancouver 3, Canada. Date  shall  March 25. 1960  Columbia,  thesis  for financial permission.  i j  ABSTRACT I t was t h e purpose o f t h i s s t u d y t o compare p u l p s p r e p a r e d from n o r m a l , sound wood w i t h t h o s e p r e p a r e d from j u v e n i l e wood, c o m p r e s s i o n wood, t e n s i o n wood and decayed wood w i t h r e g a r d t o t h e i r a p p a r e n t degree o f c r y s t a l l i n i t y . The c r y s t a l l i n i t y i n d e x and c r y s t a l l i n i t y r a t i o o f the  p u l p s p r e p a r e d from t h e s e woods ?;ere d e t e r m i n e d by two  d i f f e r e n t X - r a y methods.  I n method A, t h e p r i n c i p l e o f t h e  Debye-Scherrer powder t e c h n i q u e was a p p l i e d and t h e c r y s t a l l i n i t y i n d e x o f t h e p u l p was e v a l u a t e d from the 002 peak o f t h e X - r a y d i f f r a c t i o n p a t t e r n .  I n method B a G e i g e r -  c o u n t e r X - r a y s p e c t r o m e t e r was used and t h e c r y s t a l l i n i t y r a t i o o f h o l o c e l l u l o s e was e v a l u a t e d from t h e (101 + 1 0 1 ) c o m b i n a t i o n peak. I t was found t h a t t h e apparent c r y s t a l l i n i t y o f wood p u l p and h o l o c e l l u l o s e p r e p a r e d from normal w e s t e r n hemlock wood i n c r e a s e d s i g n i f i c a n t l y t h r o u g h s u c c e s s i v e growth r i n g s from t h e p i t h t o about 15 y e a r s , a f t e r w h i c h i t r e a c h e d a more or l e s s c o n s t a n t v a l u e .  The c r y s t a l l i n i t y o f  wood p u l p and h o l o c e l l u l o s e o f summerwood was s i g n i f i c a n t l y h i g h e r t h a n t h a t o f springwood.  The c r y s t a l l i n i t y o f wood  p u l p and h o l o c e l l u l o s e o f compression wood from Douglas f i r was c o n s i d e r a b l y lower t h a n t h a t o f normal wood, whereas t h e c r y s t a l l i n i t y o f t e n s i o n wood from cottonwood was  il  s i g n i f i c a n t l y h i g h e r t h a n t h a t o f normal wood.  The  c r y s t a l l i n i t y o f cottonwood and Douglas f i r h o l o c e l l u l o s e i n c r e a s e d s i g n i f i c a n t l y d u r i n g t h e i n c i p i e n t stage o f decay. The r a t e o f i n c r e a s e i n c r y s t a l l i n i t y was v e r y r a p i d d u r i n g the i n c i p i e n t stage o f decay r e p r e s e n t e d by a s i x p e r c e n t weight  l o s s , but became v e r y slow and showed an almost  v a l u e t h e r e a f t e r . The r e l a t i v e v a l u e o f c r y s t a l l i n i t y  constant after  decay depends m a i n l y on t h e i n i t i a l c r y s t a l l i n i t y r a t h e r t h a n t h e h i s t o r y o f decay.  ill  ACKNOWLEDGEMENT  The  author wishes t o express h i s s i n c e r e g r a t i t u d e  t o t h e F a c u l t y of F o r e s t r y of the U n i v e r s i t y of B r i t i s h Columbia, and t o Dr. R.W. Wellwood under whose this  study was c a r r i e d  careful  direction  out; t o Mr. R.W. Kennedy f o r h i s  review and c r i t i c i s m  of the manuscript  and f o r  p r o v i d i n g some experimental m a t e r i a l ; t o Dr. J.H.G. Smith for  suggesting a s t a t i s t i c a l d e s i g n ; t o Dr. L.D. Hayward f o r  d i s c u s s i o n s i n t h e p l a n n i n g stage; t o Dr. J.A.F. Gardner and Mr. W.V. Hancock o f the Vancouver L a b o r a t o r y , F o r e s t  Products  L a b o r a t o r i e s of Canadaj Dr. V.G. G r i f f i t h s , Dr. E . Teghtsonian, and Mr. Y . I . S s u of the Department of Mining and M e t a l l u r g y at  the U n i v e r s i t y of B r i t i s h Columbia and Mr. G.E. Breeze  and Mr. R.H. M l b e r g Columbia Research  of the Department o f P h y s i c s , B r i t i s h  C o u n c i l f o r p e r m i s s i o n t o use t h e i r .  equipment and f o r t h e i r  k i n d a s s i s t a n c e and c o o p e r a t i o n i n  many ways; and t o the N a t i o n a l Research  C o u n c i l of Canada  f o r the s t u d e n t s h i p grant under which t h i s work was completed.  iv  TABLE OF CONTENTS PAGE I. II.  1  INTRODUCTION CRYSTALLINE STRUCTURE AND CRYSTALLINITY OF CELLULOSE A.  4  Chain s t r u c t u r e and f o r m a t i o n o f the crystalline  5  region  B.  Lattice structure  C.  Crystallinity  7 11  of c e l l u l o s e  1.  Concept  2.  D e t e r m i n a t i o n of c r y s t a l l i n i t y (a)  11  , . . . . .  15  Chemical methods i) ii) iii)  A c i d h y d r o l y s i s method Deuteration  . . .  v) (b)  Cellulose derivative 18  ii) iii)  iv) 3.  Oxidation  19  method  Iodine s o r p t i o n method  P h y s i c a l methods i)  15 17  method  method iv)  14  . . .  20  .  21 21  X-ray method . . .  25  spectroscopy method . . . .  26  M o i s t u r e r e g a i n method Infra-red  absorption  28  D e n s i t y method  Treatments a f f e c t i n g c r y s t a l l i n i t y  . . .  29  (a)  Hydrolysis  29  (b)  Heat  30  V  PAGE (c)  Mechanical d e e r y s t a l l i z a t i o n . . . .  31  (d)  D e g r a d a t i o n by m i c r o o r g a n i s m s  32  (e)  Lattice transition i)  ...  33  T r a n s i t i o n from c e l l u l o s e I 33  to c e l l u l o s e I I ii)  Transition  from c e l l u l o s e I 34  to cellulose I I I ill)  T r a n s i t i o n from c e l l u l o s e I I and I I I t o c e l l u l o s e IV .  4.  (f)  Pulping  35  (g)  Stretching  36  Relationship properties  III.  35  between c r y s t a l l i n i t y and 36  of c e l l u l o s e  (a)  Young's modulus  37  (b)  Tensile  38  (c)  Elongation  39  (d)  Alpha c e l l u l o s e content  39  (e)  Swelling  strength  and d i m e n s i o n a l s t a b i l i t y  .  40  EXPERIMENTAL METHOD  42  A.  Materials  42  B.  S t a t i s t i c a l design  43  C.  P r e p a r a t i o n o f samples  44  D.  1.  Wood p u l p sample  2.  Hollocellulose  X - r a y c o l l i m a t i n g system and p r o c e d u r e  .  45 46  ...  47  vi  PAGE  E.  IV.  1.  Method A  47  2.  Method B . . . .  50  Evaluation of c r y s t a l l i n i t y  52  1.  Crystallinity  index  52  2.  Crystallinity  ratio  53 54  RESULTS AND DISCUSSION A.  Part I :  The degree o f c r y s t a l l i n i t y o f  pulp and h o l o c e l l u l o s e of normal wood 1.  2.  54  Results  54  (a)  T e n s i l e strength  59  (b)  A l p h a - c e l l u l o s e content  59  (c)  Moisture  60  Probable  regain  mechanism of v a r i a b i l i t y o f  crystallinity B.  . . .  Part I I :  62  i n wood  The degree of c r y s t a l l i n i t y of  pulp and h o l o c e l l u l o s e of r e a c t i o n wood as 63  compared t o normal wood  C.  1.  Results  63  2.  Compression wood  65  3.  Tension wood  66  P a r t I I I : The degree o f c r y s t a l l i n i t y o f 69  h o l o c e l l u l o s e of decayed wood 1.  Results  2.  Biochemical  3.  Preference  69 t r a n s f o r m a t i o n of c e l l u l o s e o f enzymic a t t a c k  .  73 75  vii  PAGE 4.  R e l a t i o n s h i p between l a t e r a l order and r a t e o f enzymic a t t a c k  V. VI.  77  CONCLUSIONS  82  BIBLIOGRAPHY  84  viii  LIST OF TABLES TABLE  PAGE  1.  The u n i t c e l l s t r u c t u r e of c e l l u l o s e  2.  R e l a t i o n s h i p between a l p h a - c e l l u l o s e and  3»  crystallinity  content  .  40  V a r i a t i o n i n c e l l u l o s e p r o p e r t i e s as crystallinity  4.  11  increases  .  E f f e c t o f age and season on c r y s t a l l i n i t y o f wood pulp and h o l o c e l l u l o s e  5.  55  A n a l y s i s of variance of c r y s t a l l i n i t y i n Table 4  57  6.  Crystallinity  7.  A n a l y s i s of v a r i a n c e o f c r y s t a l l i n i t y  64  o f r e a c t i o n wood  64  i n Table $ 8.  Crystallinity  r a t i o o f h o l o c e l l u l o s e of 70  decayed wood 9.  A n a l y s i s of variance  of c r y s t a l l i n i t y  Stepwise b i o c h e m i c a l of c e l l u l o s e  ratio 70  i n Table 8 10.  41  transformation 74  ix  LIST OF FIGURES FIGURE  PAGE  1.  U n i t c e l l of c e l l u l o s e  2.  Camera arrangement  Effect  9  f o r the Debye-Scherrer  powder technique 3'  I  .  48  of X-ray exposure time on  crystallinity  index  48  4.  Wood pulp X-ray diagram  49  5.  Spectrometer geometry  51  6.  X-ray d i f f r a c t i o n spectrum  51  7.  V a r i a t i o n of c r y s t a l l i n i t y w i t h age and season  8.  5&  X-ray d i f f r a c t i o n s p e c t r a of Douglas f i r 71  holocellulose 9.  Effect  of decay and type of wood on  c r y s t a l l i n i t y r a t i o of holocellulose 10.  Schematic l a t e r a l order d i s t r i b u t i o n and sequence crystalline  . . .  72  curve  of enzymic a t t a c k on the region  8l  INTRODUCTION The e f f e c t of c r y s t a l l i n i t y  on 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 c e l l u l o s e and i t s d e r i v a t i v e s has been s t u d i e d e x t e n s i v e l y d u r i n g the past few y e a r s , p a r t i c u l a r l y d u r i n g the l a s t decade.  Rapid developments i n equipment, as w e l l as  improvement i n p r e c i s e t e c h n i q u e s , have made such k i n d s o f s t u d i e s f r u i t f u l i n adding v a l u a b l e i n f o r m a t i o n t o knowledge of  c e l l u l o s e chemistry.  Most o f these works d e a l w i t h pulp or  c o t t o n c e l l u l o s e , but o n l y a l i m i t e d number o f papers w i t h the c r y s t a l l i n i t y  o f wood i n the l i g h t  deal  o f the r e s u l t s  w i t h c o t t o n c e l l u l o s e , y e t i t may be one o f the important f a c t o r s which w i l l d i r e c t l y or i n d i r e c t l y a f f e c t wood p r o p e r t i e s and  quality. The main d i f f i c u l t i e s i n s t u d y i n g c r y s t a l l i n i t y of  wood a r e caused by the complicated chemical composition o f wood itself.  I t i s w e l l known t h a t wood c o n t a i n s o n l y about 50 t o  60 percent of c e l l u l o s e .  I n order t o determine  the c r y s t a l l i n i t y  q u a n t i t a t i v e l y , the chemical c o n s t i t u e n t s other than c e l l u l o s e should be removed.  Since there i s no method which can e x t r a c t  components other than c e l l u l o s e without degrading  cellulose  molecular c h a i n s , the experimental value o f c r y s t a l l i n i t y determined  from such c e l l u l o s e can h a r d l y be c o n s i d e r e d the  same as t h a t which a c t u a l l y e x i s t e d i n the o r i g i n a l wood. However, i f the same chemical treatment  i s applied to d i f f e r e n t  types o f wood assuming a uniform degree o f d e g r a d a t i o n o f the  2  c e l l u l o s e molecular chains d u r i n g the treatment,  i t may be  p o s s i b l e t o compare the r e l a t i v e degree of c r y s t a l l i n i t y  among  wood samples. Based on t h i s premise,  s t u d i e s on c r y s t a l l i n i t y of  wood f i b r e s have been made by v a r i o u s workers.  The  c r y s t a l l i n i t y o f Cross and Bevan c e l l u l o s e prepared from wood of d i f f e r e n t ages was s t u d i e d by P r e s t o n , Hermans, and Weidinger  (113)  by means of an X-ray method.  R e s u l t s showed  t h a t the c r y s t a l l i n i t y decreased w i t h age. An opposite r e s u l t was obtained by T a n i g u c h i (142), who found t h a t a b s o l u t e c r y s t a l l i n e c e l l u l o s e content of Pinus d e n s i f l o r a , as determined by an a c i d h y d r o l y s i s method, i n c r e a s e d w i t h age s l o w l y i n the e a r l y stage o f growth. observed,  Because of these d i f f e r e n t  results  f u r t h e r study was deemed n e c e s s a r y i n order t o  a s c e r t a i n the v a r i a b i l i t y  o f c r y s t a l l i n i t y w i t h age o f wood.  L i n d g r e n (77) has p o i n t e d out t h a t the summerwood gives a sharper X-ray diagram, which i n d i c a t e s a h i g h e r degree of c r y s t a l l i n i t y as compared w i t h the corresponding  springwood.  A s i m i l a r r e s u l t was observed by H o l z e r and Lewis (57)» who claimed t h a t the summerwood f i b r e s e x h i b i t e d an u n u s u a l l y h i g h degree o f p r e f e r r e d o r i e n t a t i o n among the c r y s t a l l i t e s ,  whereas  springwood f i b r e s were found t o be much more amorphous. Numerical  data were not g i v e n by these workers. The c r y s t a l l i n i t y  of t e n s i o n wood has been s t u d i e d  thoroughly by Wardrop and Dadswell  (154,157)•  A significantly  3  h i g h degree of c r y s t a l l i n i t y  of t e n s i o n wood, as compared w i t h  t h a t o f normal wood, was found t o be due t o the e x i s t e n c e o f an a d d i t i o n a l l a y e r i n s i d e the i n n e r l a y e r o f the secondary c e l l wall. the been  To the w r i t e r ' s knowledge,  the c r y s t a l l i n i t y of  other type o f r e a c t i o n wood, compression wood,.has not studied. The r e l a t i o n s h i p between c r y s t a l l i n i t y and micro-  b i o l o g i c a l d e g r a d a t i o n o f c e l l u l o s e has been s t u d i e d by v a r i o u s workers.  Most o f these works a r e c o n f i n e d t o pure c e l l u l o s e  which has been t r e a t e d w i t h enzymes, but l i t t l e the  r e l a t i o n s h i p between c r y s t a l l i n i t y and wood decay.  C r y s t a l l i n i t y o f decayed wood was f i r s t Okamoto ( 7 1 ) . the  i s known about  s t u d i e d by Kohara and  They found a h i g h e r degree of c r y s t a l l i n i t y i n  o l d timbers taken from t e n o l d Buddhist temples ( i n use  about 300 t o 13OO y e a r s ) as compared w i t h t h a t o f new t i m b e r s . But the v a r i a t i o n i n c r y s t a l l i n i t y  o f decayed wood as r e l a t e d  t o the stage of decay s t i l l remains unknown. The purposes o f t h i s t h e s i s a r e t o q u a n t i t a t i v e l y study (1)  the v a r i a t i o n i n c r y s t a l l i n i t y  of wood from a young  t r e e w i t h age, (2) the degree o f c r y s t a l l i n i t y  o f summerwood as  compared w i t h t h a t o f springwood, (3) the c r y s t a l l i n i t y of r e a c t i o n wood as compared w i t h t h a t of normal wood, and (4) the r e l a t i o n s h i p between c r y s t a l l i n i t y and wood decay.  CRYSTALLINE STRUCTURE AND CRYSTALLINITY OF CELLULOSE As e a r l y as 1913>  Nishikawa and Ono (104) showed  t h a t t h e X-ray diagram of c e l l u l o s e c o n s i s t e d of d e f i n i t e diffraction rings.  T h i s d i s c o v e r y l e d t o the concept o f  c r y s t a l l i n i t y of f i b r e s .  Nishikawa (105)  l a t e r p o i n t e d out  t h a t the c r y s t a l l i z e d areas were not continuous, but separated by more or l e s s d i s o r d e r e d m a t e r i a l .  Extensive research,  both p h y s i c a l and c h e m i c a l , has been c a r r i e d out s i n c e then, but the concept  remains the same.  Today, i t i s s t i l l  t h a t c e l l u l o s e , l i k e other h i g h polymers, w i l l under proper  considered  crystallize  conditions t o form an i m p e r f e c t l y ordered  solid,  having c e r t a i n r e g i o n s p o s s e s s i n g a h i g h degree of i n t e r n a l g e o m e t r i c a l order known as c r y s t a l l i t e s .  The remainder w i l l  possess d i s o r d e r e d entangled c h a i n molecules  known as amorphous  regions. As the s i z e , shape, arid degree of p e r f e c t i o n i n the c r y s t a l l i n e r e g i o n , or the degree of randomness I n the amorphous r e g i o n , are never constant from sample t o sample, the p h y s i c a l and chemical p r o p e r t i e s of c e l l u l o s e and i t s d e r i v a t i v e s are c o r r e s p o n d i n g l y v a r i a b l e . understand  I n order t o  the c r y s t a l l i n i t y r e l a t i o n s h i p s of c e l l u l o s e , a  b r i e f review  i s necessary  of the c r y s t a l l i n e s t r u c t u r e and  c r y s t a l l i n i t y of c e l l u l o s e .  5  A.  Chain s t r u c t u r e and f o r m a t i o n of the c r y s t a l l i n e r e g i o n To e s t a b l i s h the c h a i n s t r u c t u r e of c e l l u l o s e ,  studies  on q u a n t i t a t i v e y i e l d s o f glucose u n i t s from c e l l u l o s e were i n i t i a t e d , f o l l o w e d by i n v e s t i g a t i o n of the nature o f h y d r o x y l groups and p o s i t i o n o f h y d r o x y l groups i n c e l l u l o s e .  From  these works i t was concluded t h a t pure c e l l u l o s e c o n s i s t e d e x c l u s i v e l y o f glucose r e s i d u e s ( 6 6 , 9 3 ) which c o n t a i n e d three h y d r o x y l groups a t the second, t h i r d , and s i x t h carbon atom ( 2 7 , 6 7 ) » and the b a s i c u n i t was found t o be the anhydroglucose unit  (110). Nature o f the l i n k a g e between these anhydroglucose  u n i t s was s t u d i e d by v a r i o u s p h y s i c a l and chemical methods, and f i n a l l y a s p a t i a l model o f c e l l u l o s e was c o n s t r u c t e d by Meyer and Mark (110).  T h i s model had the b e t a form o f o  Haworth's c e l l o b i o s e (110) w i t h u n i t l e n g t h of 1 0 . 3 A. o  D i s t a n c e between carbon atoms was found t o be 1.54- A, whereas o  t h a t between carbon and oxygen atoms was 1.35 A.  .One h a l f of  the u n i t i s t u r n e d through 180 degrees t o f u l f i l l the screw a x i s requirement which a l l o w s the 1 , 4 - l i n k a g e . The molecular c h a i n thus formed by anhydroglucose u n i t s i s n e a r l y s t r a i g h t , w i t h a degree o f p o l y m e r i z a t i o n o f s e v e r a l thousand g l u c o s i d i c r i n g s .  These extend  longitudinally  i n the d i r e c t i o n o f the f i b r e a x i s , w i t h a s m a l l angle o f inclination.  When a l l m o l e c u l a r chains extend i n t h i s manner,  a c r o s s - w i s e secondary f o r c e w i l l be formed.  Because o f t h i s  6  i n t e r c h a i n f o r c e , the molecular another to form a w e l l - o r d e r e d  chains w i l l a t t r a c t  r e g i o n or a c r y s t a l l i n e r e g i o n .  Such c r y s t a l l i z a t i o n cannot take p l a c e completely the whole c h a i n .  one  throughout  I t occurs a t the p a r t i c u l a r r e g i o n where the  i n t e r m o l e c u l a r a t t r a c t i o n i s s t r o n g e s t , and  c h a i n molecules  are f i t t e d l a t e r a l l y i n t o a c r y s t a l l a t t i c e .  The  other  region  w i l l remain i n a d i s o r d e r e d s t a t e even though weak secondary a t t r a c t i o n f o r c e s e x i s t among them. t o as the amorphous r e g i o n .  This region i s r e f e r r e d  I t must be p o i n t e d out t h a t not  o n l y the l e n g t h of such c r y s t a l l i z e d p o r t i o n s i s v a r i a b l e , but a l s o the i n t e r v a l d i s t a n c e between them i s changeable from one  type of c e l l u l o s e t o another. The molecular  chains  i n wood c e l l u l o s e , which  may  have a degree of p o l y m e r i z a t i o n of more than 3»000 glucose o  u n i t s (145)» are approximately  l5xl0-  )  O  A i n l e n g t h , whereas a  c r y s t a l l i t e has an order of magnitude of 1.4x10° A (145). the amorphous r e g i o n , on the average, i s assumed to be than the c r y s t a l l i n e r e g i o n , then each molecular  l  f  shorter  c h a i n must  pass through about ten microphases o r , i n other words, c o n s i s t s of s e v e r a l c r y s t a l l i n e and  amorphous r e g i o n s .  was  p o s t u l a t e d f i r s t by Frey-lAfyssling (35)  and  l e d t o the f r i n g e m i c e l l a r t h e o r y .  crystalline-amorphous theory was  T h i s concept  and Kratky  As f a r as  (74),  the  m u l t i p l e s t r u c t u r e i s concerned, t h i s  i s c o n s i d e r e d p r e f e r a b l e t o the m i c e l l a r theory, which  accepted  cellulose.  b e f o r e 1930  i n order to e x p l a i n the p r o p e r t i e s of  7 The m i c e l l a r theory assumed t h a t molecular  chains  can never exceed the l e n g t h of m i c e l l e s , and amorphous 1  m a t e r i a l e x i s t s between m i c e l l e s as a cementing medium which i s r e s p o n s i b l e f o r s w e l l i n g of f i b r e s  (55)•  However, the  e x i s t e n c e of a separate cementing m a t e r i a l f a i l e d to e x p l a i n the s t r u c t u r e of regenerated  cellulose  (110).  In a d d i t i o n  c e l l u l o s e chains have been shown to be longer than the l e n g t h of a m i c e l l e , by e l e c t r o n m i c r o s c o p i c s t u d i e s and u l t r a c e n t r i f u g e and v i s c o s i t y methods (44,112).  For  these  reasons, the f r i n g e m i c e l l a r theory i s more a c c e p t a b l e . A c c o r d i n g t o the f r i n g e m i c e l l a r t h e o r y ,  the  c r y s t a l l i n e r e g i o n s a l t e r n a t e w i t h the amorphous r e g i o n s , w i t h g r a d u a l t r a n s i t i o n from the former to the l a t t e r . c l e a r border  e x i s t s between two phases, nor  between molecular B.  c h a i n l e n g t h and s i z e of  No  correlation crystallite.  Lattice Structure I t f o l l o w s t h a t c e l l u l o s i c m a t e r i a l has  a  p o l y c r y s t a l l i n e s t r u c t u r e i n which the c e l l u l o s e may  molecules  t r a v e r s e s e v e r a l c r y s t a l l i n e and amorphous r e g i o n s .  the c r y s t a l l i n e r e g i o n , the molecular  chains form an  In  ordered  l a t t i c e s t r u c t u r e i n which l a t e r a l i n t e r m o l e c u l a r d i s t a n c e i s  T h e terms " m i c e l l e " and " c r y s t a l l i t e , " although g e n e r a l l y used i n t e r c h a n g e a b l y i n s c i e n t i f i c papers, are s l i g h t l y d i f f e r e n t i n nature. The terra " m i c e l l e " i s used to designate a d e f i n i t e concept of a r e g i o n having d i s t i n c t boundaries, whereas the term " c r y s t a l l i t e " i s used without s p e c i f y i n g any p a r t i c u l a r s i z e , shape or nature of the boundary between c r y s t a l l i n e r e g i o n s (110). x  8  kept a t a minimum so t h a t an e q u i l i b r i u m i s maintained a t a minimum p o t e n t i a l energy.  Mark (85)  suggested t h a t the  amorphous r e g i o n should have a h i g h e r energy content than the c r y s t a l l i n e region.  Thus, the i n t e r c r y s t a l l i n e a r e a may  be  c o n s i d e r e d as h i g h l y d i s o r d e r e d c r y s t a l l a t t i c e s i n which s i n g l e atoms are s h i f t e d c o n s i d e r a b l y from t h e i r equilibrium positions  normal  (100).  The a n a l y s i s of l a t t i c e s t r u c t u r e has been r a p i d l y advanced by X-ray d i f f r a c t i o n t e c h n i q u e s .  I n the case of the  c e l l u l o s e l a t t i c e , the t r a n s p a r e n t d i f f r a c t i o n diagram i s g e n e r a l l y used f o r a n a l y t i c a l purposes. r e f l e c t i o n (20) the  can be c a l c u l a t e d from the X-ray diagram and  X-ray system c o n s t r u c t e d , the i n t e r p l a n e spacings can be  e a s i l y determined by Bragg's Law. been s t u d i e d on t h i s The f i r s t who  S i n c e the angle of  The u n i t c e l l  l a t t i c e has  principle. u n i t c e l l was proposed by P o l a n y i  suggested a rhombic  (110),  u n i t c e l l w i t h dimensions of  o  7 * 9 x 8 . 4 5 x 1 0 . 2 A.  A few years l a t e r , an orthorhombic u n i t  w i t h a x i s a* = 6 . 1 , was  b* = 1 0 . 2 5 , c* = 5 . 4 A, and B* = 88 degrees  suggested by S p o n s l e r ( 1 3 4 ) .  S p o n s l e r ' s s u g g e s t i o n was  f o l l o w e d by Meyer and h i s co-workers to  cell  (89>90), and f i n a l l y l e d  the p o s t u l a t i o n of a m o n o c l i n i c u n i t c e l l w i t h a x i s  a = 8.35,  b = 10.3,  and c = 7.9  A, and B = 84 degrees.  The  planes of the anhydroglucose u n i t l i e i n the a-b plane and the •The d e f i n i t i o n of a, b, c, and B are g i v e n i n F i g u r e page 9 .  1,  9 molecular  chains are p a r a l l e l to the b - a x i s of the u n i t c e l l . A few  years  l a t e r , Meyer (89)  model i n which the c e n t e r c h a i n and  suggested a r e v i s e d  corner drains were  i n o p p o s i t e d i r e c t i o n s , but the dimension of the u n i t remained the same. F i g u r e 1. i n 1938,  A model of the u n i t c e l l  T h i s s t r u c t u r e was and  i t is s t i l l  supported  generally  running cell  i s shown i n  by Gross and C l a r k  (42)  accepted.  1.  a»8-35A—*\ F i g u r e 1.  U n i t c e l l of c e l l u l o s e I (Meyer and  co-workers (110))  As mentioned p r e v i o u s l y , the f o r m a t i o n  of the u n i t  c e l l i s a t t r i b u t e d to c r y s t a l l i z a t i o n , which i s caused p r i m a r i l y by i n t e r m o l e c u l a r a t t r a c t i o n . t h r e e d i f f e r e n t types  I t has been shown t h a t there  of i n t e r m o l e c u l a r a t t r a c t i n g f o r c e s  a c t i n g i n three d i f f e r e n t d i r e c t i o n s (110,145).  Along  the  are  10 b - a x i s , 1 , 4 - g l u c o s i d i c bonds between carbon and connected by  primary v a l e n c e bonding which has  energy of about 50 k c a l . per mole. a - a x i s , where the  I n the  d i s t a n c e between the  oxygen a  are  dissociation  d i r e c t i o n of  glucosidic  the  ring i s  o  approximately 2 . 5  A,  a strong intermolecular force  i s present  i n the  form of hydrogen bonds a t t r a c t i n g  each c h a i n  i n the  a-b  an average bond  plane.  The  hydrogen bond has  energy of 5 k c a l . per  mole.  d i s t a n c e i s about 3.1  A.  The  In the  der Waal's f o r c e s between the  can be  calculated The  the  minimum  only e x i s t i n g a t t r a c t i o n i s  to van  to be  c-axis,  transversely  anhydroglucose r i n g s  2 to 3 k c a l . per  c r y s t a l l i n e structure  c e l l u l o s e I or n a t i v e c e l l u l o s e .  mole  due which  (110).  so f a r d i s c u s s e d belongs  There are  to  three other  d i f f e r e n t c r y s t a l l i n e m o d i f i c a t i o n s , depending on the  type  chemical reagent used to modify the  i.e.,  native structure,  of  c e l l u l o s e I I (hydrate c e l l u l o s e or m e r c e r i z e d c e l l u l o s e ) , cellulose III  (ammonia c e l l u l o s e )  or high-temperature c e l l u l o s e ) . structure unit  which has  c e l l structure  and  c e l l u l o s e IV  Each has  a  (cellulose T  characteristic  been s t u d i e d by v a r i o u s i n v e s t i g a t o r s . of these f o u r types of c e l l u l o s e  summarized i n Table 1,  page  11.  are  The  11 Table 1.  The u n i t c e l l s t r u c t u r e of  cellulose I  a*  cellulose II  c e l l u l o s e (110)  cellulose III  8.1  8.35  cellulose IV  8.11  7.74  b*  10.3  10.3  10.3  10.3  c*  7.9  9.1  9.9  7.9  84  62  90  58  o  •unit: **unit:  A degrees  C.  C r y s t a l l i n i t y of c e l l u l o s e  1.  Concept Although a great number of i n v e s t i g a t i o n s have been  made r e g a r d i n g the c r y s t a l l i n i t y of c e l l u l o s e , and v a l u a b l e data have been p u b l i s h e d , a proper has not y e t been e s t a b l i s h e d .  d e f i n i t i o n of c r y s t a l l i n i t y  One of the most d i f f i c u l t  problems i s t h a t there i s no b o r d e r l i n e which can be drawn between c r y s t a l l i n e and amorphous r e g i o n s .  Once t h i s problem  i s s o l v e d , t h e c r y s t a l l i n i t y o f c e l l u l o s e can be d e f i n e d as the f r a c t i o n o f c e l l u l o s e contained  simply  i n the r e g i o n i n which  h i g h l y geometric order p r e v a i l s , w i t h the d i s t a n c e between neighboring  molecules governed by s t r i c t  laws.  The amorphous  r e g i o n , a c c o r d i n g l y , must be c o n s i d e r e d t o c o n t a i n a l l p o s s i b l e intermediate  degrees o f packing  c r y s t a l l i n e state  (110).  between the l i q u i d and the  12  Various  i n v e s t i g a t o r s have approached t h i s problem  from d i f f e r e n t p o i n t s o f view by using d i f f e r e n t  definitions  of the " c r y s t a l l i n e r e g i o n , " which has l e d t o a marked disagreement i n a b s o l u t e values o f c r y s t a l l i n i t y .  For  i n s t a n c e , those who t r e a t t h i s problem from the p h y s i c a l p o i n t of view, d e f i n e t h e " c r y s t a l l i n e r e g i o n " as the p o r t i o n which i s i n the s t a t e o f p e r f e c t , three dimensional  order  and which gives r i s e t o s e l e c t i v e X-ray d i f f r a c t i o n  patterns  (44).  Any p o r t i o n which f a i l s t o produce such d i f f r a c t i o n  would be d e f i n e d as an "amorphous r e g i o n . "  On the other hand,  those who approach t h i s problem by chemical  means c o n s i d e r  the c r y s t a l l i n e r e g i o n as the p o r t i o n having t o chemical  extreme r e s i s t a n c e  a t t a c k , as compared w i t h the r e s t o f the r e g i o n  which i s a c c e s s i b l e .  On treatment w i t h c e r t a i n chemical  reagents  c o n d i t i o n s , the r e s i d u e i s c o n s i d e r e d as  under proper  the c r y s t a l l i n e r e g i o n w h i l e the r e s t i s the amorphous r e g i o n . Because o f t h e i r d i f f e r e n t approaches, the r e s u l t s have never coincided.  The p h y s i c a l method always g i v e s lower  c r y s t a l l i n i t y than the chemical method.  absolute  A detailed discussion  of the d i f f e r e n c e , i n r e s u l t s between these methods w i l l be given l a t e r . i n t h i s  thesis.  Since the p h y s i c a l method and the chemical always  give  method  c o n s i d e r a b l y d i f f e r e n t values of c r y s t a l l i n i t y ,  some i n v e s t i g a t o r s p r e f e r t o use the term "degree o f l a t e r a l order"  (55,84,110) r a t h e r than "degree of c r y s t a l l i n i t y . "  concept of degree of l a t e r a l order i s based on the f r i n g e  The  1  m i c e l l a r theory as d e s c r i b e d above. r e g i o n i n a g i v e n c e l l u l o s e may of p e r f e c t i o n , and  That i s , the  3  crystalline  v a r y i n s i z e , shape and  degree  i s heterogenous r a t h e r than homogeneous as  f a r as the order l e v e l i s concerned.  T h e r e f o r e a complete  s t a t i s t i c a l d i s t r i b u t i o n of degree of p e r f e c t i o n of the c r y s t a l l i n e r e g i o n i s of g r e a t e r importance than merely specifying absolute c r y s t a l l i n i t y .  Howsman and S i s s o n , as  c i t e d i n Ott et a l (110), d e f i n e d the degree of order by following  the  equation: 0 = ( 0H ) C  / ( 0H  where 0 i s a degree of o r d e r , (0H ) C  )  t  i s the t o t a l number of  hydrogen bonds a c t u a l l y present i n the r e g i o n , and  ( OH^. ) i s  the t o t a l p o s s i b l e number of hydrogen bonds i f a l l molecules are p e r f e c t l y c r y s t a l l i z e d .  I f i t i s considered that d e f i n i t e  q u a n t i t i e s of c e l l u l o s e q^, q , 2  a s s o c i a t e d w i t h the order 0^,  q^,  02>  q  can be  n  0^,  0 , n  l a t e r a l - o r d e r d i s t r i b u t i o n curve can be obtained  then a  by  d i f f e r e n t i a t i n g the summative mass-order curve i n which corresponding values o f q are p l o t t e d a g a i n s t 0. order i n t h i s case corresponds  to a h i g h  lateral  crystallinity.  T h i s i d e a has p r a c t i c a l experimental f a r as the r e s o l u t i o n i s concerned,  A high  difficulties  as  s i n c e i t i s dependent on  the c h o i c e of the o r i g i n a l volume element.  From the  p o i n t of view, sooner or l a t e r the d i s t r i b u t i o n  theoretical  curve  e v a l u a t i o n w i l l be commonly adopted i n the f i e l d of s t r u c t u r e s t u d i e s of c e l l u l o s e .  14  1  2.  D e t e r m i n a t i o n of c r y s t a l l i n i t y I t has been s t a t e d t h a t methods f o r d e t e r m i n a t i o n  c r y s t a l l i n i t y of c e l l u l o s e chemical and p h y s i c a l .  of  can be c l a s s i f i e d i n t o two groups,  Generally  speaking, the chemical  methods assume t h a t chemical reagents are unable t o penetrate i n t o the c r y s t a l l i n e r e g i o n , thus the r e a c t i o n takes p l a c e very r a p i d l y i n the i n i t i a l slow.  stage and f i n a l l y becomes  very  The r a t e of r e a c t i o n and percentage of c e l l u l o s e  r e a c t e d are used as the measure of the a c c e s s i b i l i t y .  The  p h y s i c a l methods, on the other hand, measure c r y s t a l l i n i t y on the b a s i s t h a t the c r y s t a l l i n e r e g i o n i s assumed t o give  high  X-ray d i f f r a c t i o n , h i g h d e n s i t y , or low moisture r e g a i n .  In  the u s u a l case, the chemical method p r i m a r i l y measures the a c c e s s i b l e or amorphous f r a c t i o n , whereas the p h y s i c a l method, i n g e n e r a l , measures the c r y s t a l l i n e I t should  region.  be noted t h a t the a c c e s s i b l e c e l l u l o s e i s  not necessary e q u i v a l e n t  to non-crystalline c e l l u l o s e .  can be demonstrated by the f o l l o w i n g equation A = o-d< +  This  (36):  ( 100 - <*)  where A i s the percentage of a c c e s s i b l e c e l l u l o s e i n the sample, 0- i s the f r a c t i o n of the c e l l u l o s e o c c u r r i n g i n the s u r f a c e of the c r y s t a l l i n e r e g i o n , and c * i s the percentage of c r y s t a l l i n e c e l l u l o s e i n the sample. it  From the above  equation,  immediately f o l l o w s t h a t A i s dependent upon the s i z e of  c r y s t a l l i t e as w e l l as the f r a c t i o n of c r y s t a l l i n e c e l l u l o s e . Since  cr- i s not e a s i l y determined, most chemical methods do  15  not make adequate d i s t i n c t i o n between a c c e s s i b l e and noncrystalline cellulose. t h i s e q u a t i o n should  I f an a c c u r a t e  r e s u l t i s required,  be taken i n t o account.  Both chemical and p h y s i c a l methods g i v e the crystallinity absolute  i n e i t h e r absolute  values  or r e l a t i v e v a l u e s .  The  do not agree w i t h one another because of the  d i f f e r e n t assumptions i n v o l v e d i n the i n t e r p r e t a t i o n as noted. The d i f f e r e n c e i s p a r t i c u l a r l y d i s t i n c t between the a c i d h y d r o l y s i s method and the X-ray method, which w i l l be described  i n detail i n a later section.  crystallinity  f o r various  The r e l a t i v e order of  c e l l u l o s e preparations  as determined  by both methods i s the same.  The order  crystallinity  h i g h - t e n a c i t y rayon, t e x t i l e  i s as f o l l o w s :  of i n c r e a s i n g  rayons, F o r t i s a n , m e r c e r i z e d c o t t o n , wood p u l p , and c o t t o n . The methods f o r determining c r y s t a l l i n i t y published (a)  so f a r  i n the t e c h n i c a l l i t e r a t u r e a r e d e s c r i b e d below.  Chemical methods i)  A c i d h y d r o l y s i s method The b a s i s of the a c i d h y d r o l y s i s method i s t h a t the  i n t e r c r y s t a l l i n e c h a i n network i s c h e m i c a l l y more r e a c t i v e than i s the I n a c c e s s i b l e c e l l u l o s e i n the c r y s t a l l i n e Thus the d i s o r d e r e d  c h a i n segments are more r a p i d l y  region.  attacked  by the a c i d , and the amount of n o n - c r y s t a l l i n e c e l l u l o s e i s estimated from the r a t e of h y d r o l y s i s .  16  N i c k e r s o n was  the f i r s t  to apply  the r a t e of  h y d r o l y s i s i n H CI - F e C l ^ reagent to evaluate  (96,97,98,101,102,103).  a c c e s s i b i l i t y of c e l l u l o s i c m a t e r i a l s The  c e l l u l o s e i s f i r s t hydrolyzed  o x i d i z e d to C0 . 2  By  the  to glucose, which i s then  comparing the r a t e of CO2  evolution  w i t h t h a t of glucose o x i d i z e d under s i m i l a r c o n d i t i o n s , r a t e of h y d r o l y s i s i s c a l c u l a t e d and time of h y d r o l y s i s . g i v e s two  The  p l o t t e d against  h y d r o l y s i s r a t e curve thus  d i f f e r e n t r a t e s , being  r a p i d during  or three hours of r e a c t i o n p e r i o d and l a t e r stage.  t h i s technique was Two  then slowing  The  the obtained  the f i r s t  A c c e s s i b i l i t y i s determined by  the slow r a t e p e r i o d to zero time.  the  two  at a  extrapolating  r e p r o d u c i b i l i t y of  g r e a t l y improved by Conrad and  (22).  Scroggie  more independent i n v e s t i g a t i o n s ( 8 0 , 9 5 ) were  undertaken i n which the r e s i s t a n t r e s i d u e was  used as a means  of f o l l o w i n g the course of h y d r o l y s i s .  hydrolyzing  Other  agents, such as s u l f u r i c a c i d , have a l s o been used i n s t e a d h y d r o c h l o r i c a c i d , but  i t was  l e s s a c t i v e as a h y d r o l y z i n g equivalent  concentration  found t h a t s u l f u r i c a c i d  methods. method.  (103). considerably  of the amorphous f r a c t i o n as compared w i t h  other  T h i s i s p a r t i c u l a r l y t r u e as compared w i t h the X-ray The  probable r e a s o n f o r t h i s f a c t i s t h a t the c u t t i n g  of i n t e r c r y s t a l l i n e c h a i n allows  was  agent than h y d r o c h l o r i c a c i d of  In g e n e r a l , a c i d h y d r o l y s i s gives lower values  of  segments removes r e s t r a i n t s and  the l o o s e c h a i n ends freedom to undergo r e c r y s t a l l i z a t i o n .  17  ii)  D e u t e r a t i o n method  Bpnhoeffer (12) was the f i r s t  t o observe the  r e a c t i o n o f heavy water w i t h the OH group o f c e l l u l o s e . L a t e r Champetier and V i a l l a r d and  lint  (15)  c e l l u l o s e were completely  claimed  that f i l t e r  paper  a c c e s s i b l e t o D 0 and t h a t 2  exchange was completed i n 36 hours a t 30°C.  F r i l e t t e , Hanle  and Mark (36) d e v i s e d a method o f d i g e s t i n g pulp i n water of h i g h deuterium content. to  Exchange o f H 0 and D 0 was permitted 2  2  occur and the r a t e o f a b s o r p t i o n of D 0 was determined as 2  a f u n c t i o n of time. technique,  these  By using a s i m i l a r method w i t h  improved  i n v e s t i g a t o r s obtained a r a t e curve i n which  the i n i t i a l r a p i d r e a c t i o n g r a d u a l l y slowed down and became v i r t u a l l y complete i n f o u r hours.  The f r a c t i o n which had not  r e a c t e d a f t e r f o u r hours was i d e n t i f i e d as h i g h l y material.  T h i s c o n c l u s i o n was f u r t h e r confirmed  ordered by Rowen and  P l y l e r ' s s t u d i e s by means of i n f r a - r e d spectroscopy Q u a n t i t a t i v e study.of spectroscopy  (121).  d e u t e r a t i o n by i n f r a - r e d  was extended by A l m i n ( 1 ) , and f o l l o w e d by Mann  and Marrinan ( 8 3 , 8 7 ) .  The l a t t e r demonstrated the p o s s i b i l i t y  of d i s t i n g u i s h i n g between the d e u t e r a t i o n o f the c r y s t a l l i n e and t h a t o f the amorphous r e g i o n from the shape o f the a b s o r p t i o n band i n the 3600 t o 3000 cm."  1  range.  They a l s o  found t h a t the i s o t o p i c exchange r e a c t i o n between the OH group o f c e l l u l o s e and l i q u i d D 0 gave a measure o f 2  a c c e s s i b i l i t y and not the c r y s t a l l i n i t y o f c e l l u l o s e .  By  d e u t e r a t i o n i n the vapor phase i t was p o s s i b l e t o a v o i d  18  d e u t e r a t i n g c r y s t a l l i n e r e g i o n s , thus an estimate of the percentage  o f c r y s t a l l i n i t y was o b t a i n e d .  I n t h i s case, the  c r y s t a l l i n i t y of c e l l u l o s e was d e f i n e d as the f r a c t i o n o f OH groups which were hydrogen-bonded i n a r e g u l a r c r y s t a l l i n e manner.  The r e l a t i v e v a l u e of c r y s t a l l i n i t y determined by  t h i s method agreed r e a s o n a b l y w e l l w i t h v a l u e s found by Hermans ( 8 3 ) .  S i n c e no c r y s t a l i z a t i o n takes p l a c e d u r i n g the  d e t e r m i n a t i o n , the v a l u e o f a c c e s s i b i l i t y i s , t h e r e f o r e , much h i g h e r than t h a t e v a l u a t e d by. an a c i d h y d r o l y s i s method. iii)  C e l l u l o s e d e r i v a t i v e method  D e t e r m i n a t i o n of a c c e s s i b i l i t y by e t h e r i f i c a t i o n was i l l u s t r a t e d by A s s a f , Hass and Purves  (7).  C e l l u l o s e was  t r e a t e d w i t h t h a l l o u s e t h y l a t e t o form a t h a l l o u s  derivative,  which r e a c t s w i t h methyl i o d i d e t o y i e l d t h a l l o u s i o d i d e and methyl c e l l u l o s e .  A n a l y s i s of methyl c e l l u l o s e f o r methoxyl  content y i e l d s a measure of the a c c e s s i b l e OH groups.  This  method can be c a r r i e d out i n a non-aqueous system as w e l l as an aqueous system.  The l a t t e r system u s u a l l y g i v e s h i g h e r  a c c e s s i b i l i t y value than the former due  t o the medium.  one because o f s w e l l i n g  The r e s u l t a c t u a l l y obtained by these  workers i n a non-aqueous system was the lowest v a l u e ever r e p o r t e d f o r the chemical method  accessibility  (110).  Tarkow (144) and N i c k e r s o n ( 9 9 ) have demonstrated a f o r m i c a c i d e s t e r i f i c a t i o n procedure a c c e s s i b i l i t y of c e l l u l o s e .  f o r evaluation of  T h i s method i s based  on the  19  a s s u m p t i o n t h a t t h e e s t e r i f i c a t i o n o f w h i t e d e x t r i n and c e l l u l o s e are i d e n t i c a l chemical processes.  The r a t i o o f  combined f o r m i c a c i d f o r c e l l u l o s e t o t h a t o f d e x t r i n , under i d e n t i c a l c o n d i t i o n s , p r o v i d e s an e s t i m a t e o f t h e a c c e s s i b l e f r a c t i o n of c e l l u l o s e . iv)  O x i d a t i o n method The o x i d a t i o n of c e l l u l o s e w i t h sodium p e r i o d a t e i n  aqueous s o l u t i o n was s t u d i e d by G o l d f i n g e r , Mark and S i g g i a (40).  The p e r i o d a t e  i o n i s known t o a t t a c k t h e second and  t h i r d p o s i t i o n of t h e g l u c o s e a n h y d r i d e u n i t by s p l i t t i n g t h e g l y c o l c o n f i g u r a t i o n and c o n v e r t i n g  i t t o two c a r b o n y l  groups.  A r e a c t i o n r a t e c u r v e s i m i l a r t o t h a t o f a c i d h y d r o l y s i s was obtained.  By e x t r a p o l a t i o n of t h e e x t r e m e l y slow r a t e c u r v e ,  the amount o f amorphous component was e v a l u a t e d .  Recrystalli-  z a t i o n probably takes place during the o x i d a t i o n  (110).  Roseveare and S p a u l d i n g (120) demonstrated a n o t h e r o x i d a t i o n method by t r e a t i n g c e l l u l o s e w i t h n i t r o g e n i n carbon t e t r a c h l o r i d e .  dioxide  I t has been shown (37>120) t h a t  chromic a c i d a c t s v e r y l a r g e l y on t h e amorphous r e g i o n  while  p e r i o d i c a c i d a c t s on t h e c r y s t a l l i n e r e g i o n as w e l l .  Thus  Glegg (38)  o x i d i z e d c e l l u l o s e w i t h chromium t r i o x i d e i n  a c e t i c a c i d - a c e t i c a n h y d r i d e s o l u t i o n and e v a l u a t e d accessibility.  T h i s method showed a f a i r l y good c o r r e l a t i o n  w i t h t h e t h a l l o u s e t h y l a t e method over a 2 0 0 - f o l d accessibility  the  (7).  range o f  20  v)  Iodine sorption- method In order  t o know the m e r c e r i z a t i o n  c e l l u l o s e and the degree of m e r c e r i z a t i o n , developed a technique f o r d e t e r m i n a t i o n (124,125»126,127).  e f f e c t s on  Schwertassek  of iodine  sorption  On the b a s i s o f h i s s e r i e s o f experiments,  he concluded t h a t i o d i n e s o r p t i o n c o u l d be used as a measure of the amorphous f r a c t i o n o f c e l l u l o s e .  A decrease i n i o d i n e  s o r p t i o n i s an i n d i c a t i o n o f an i n c r e a s e  i n crystallinity.  The method was a p p l i e d by He.ssler. and Power (59) i n the study of v a r i o u s  treatment e f f e c t s on c o t t o n c e l l u l o s e .  the weight of I  2  A r a t i o of  absorbed by c e l l u l o s e t o t h a t absorbed by  methocel gave a value f o r the amorphous f r a c t i o n . The c r y s t a l l i n i t y was obtained  by s u b t r a c t i n g the percent o f  amorphous m a t e r i a l from 1 0 0 . R e s u l t s were i n good agreement w i t h the value obtained  by.other chemical methods.  temperature a t which the a d s o r p t i o n s p e c i f i e d , s i n c e the a d s o r p t i o n  To apply t h i s method, the i s c a r r i e d out should be  i s g r e a t l y dependent upon the  temperature, as claimed by C h i t a l e (1(5).  T h i s method was a l s o  c r i t i c i s e d by Majury ( 8 2 ) , who showed t h a t the s o r p t i o n of i o d i n e by c e l l u l o s e a c e t a t e  could not be i n t e r p r e t e d s o l e l y i n  terms of s o r p t i o n by amorphous m a t e r i a l s .  Thus q u a n t i t a t i v e  a p p l i c a t i o n of t h i s method t o c e l l u l o s e f i b r e may need t o be reviewed.  21  (b)  P h y s i c a l methods i)  X-ray method Among the p h y s i c a l methods, the X-ray method i s the  most widely used q u a n t i t a t i v e method f o r c r y s t a l l i n i t y evaluation.  Since i t i s a p p l i e d i n t h i s study, a more  d e t a i l e d d e s c r i p t i o n of i t s p r i n c i p l e and procedure i s given i n this section. When a f i b r e sample i s exposed to a narrow X-ray beam, the i n t e r f e r e n c e corresponding t o the c r y s t a l l o g r a p h i c plane gives r i s e to s e l e c t i v e d i f f r a c t i o n which appears on an X-ray diagram as black spots.  Generally speaking, c e l l u l o s e ,  produces three intense i n t e r f e r e n c e spots arranged symmetrically along the equator of an X-ray diagram.  These  three i n t e r f e r e n c e spots are d i f f r a c t e d from the 101, 101 and 002 plane of the u n i t c e l l r e s p e c t i v e l y .  For wood f i b r e s ,  the X-ray diagram shows only two i n t e r f e r e n c e spots since the i n t e r f e r e n c e caused by the 101 and 101 planes are combined. I f the randomly oriented f i b r e specimen i s r o t a t e d at constant speed during the X-ray exposure, two d i s t i n c t i n t e r f e r e n c e r i n g s appear instead of two i n t e r f e r e n c e spots. A densitometer curve along the equator of the X-ray diagram i s u s u a l l y reproduced from the X-ray diagram.  Two  i n t e r f e r e n c e spots or i n t e r f e r e n c e r i n g s w i l l appear as two i n t e r f e r e n c e peaks i n the densitometer curve.  From t h i s curve,  the i n t e n s i t y , p o s i t i o n , and r a d i a l width of the i n t e r f e r e n c e  22  peaks  c a n be  calculate such  as  measured.  data  the  molecular  the  chains,  background  (44).  of  are  the  of  a  gives  and  crystal  Is  not  always  background also  doubtful.  contribute as  is  to  a  chains.  This  increase  the  certain  magnitude. the  cellulose  is  the in  surface  material,  discontinuity means  that  background  of  the  the  fraction of  order  of  X-rays  portion  i n  the  chain  d i f f r a c t i o n  assumption order  of  is  based  the  constant  in  a l l  cellulose.  l a t e r a l  the  layer  to  of  previous  by  concerned,  c r y s t a l l i n i t y .  the  p r a c t i c a l l y  of  caused  extent  This  concept the  of  X-ray  degree  solely  some  as  is  c r y s t a l l i n e  degree  i t s e l f  Furthermore,  non-crystalline  represents  a  c r y s t a l l i n i t y .  d i f f r a c t i o n  the  cellulose  diffuse  of  as  of  of  the  measure  selective  true.  The  and  defined  that  mentioned  peaks  that  to  cellulose,  c r y s t a l l i n i t y  is  of  of  degree  case  assumes  to  and  a  modifications  According distribution  of  used  orientation  as  reflect  of  c e l l ,  taken  r i s e  definite  areas  unit  are  structure  micelles,  this  presupposition  crystalline types  i n  would  fine  degree  represents  which  parameters  interference  definition  cellulose  intensity  of  the  the  a  generally  which  This  system  on  as  to  of  size  c r y s t a l l i n i t y  cellulose  of  far  intensity  The  pertinent  dimension  As  These  section,  causing  decreasing scattering.  that  w i l l  background  the  some size  assumption  surface  These  the two  is  also scattering  of  micelles  displacement of  diffuse  fraction,  micelles  X-ray  because  this  assumption  amorphous of  order  of  micelles points  the w i l l  should  be  23  understood before the X-ray method i s applied. X-ray methods so far developed can be summarized below.  The f i r s t quantitative study of crystallinity by the  X-ray method was made by Hermans ( 4 6 ) . An X-ray photograph was taken by exposing the fibre specimen i n the form of a pellet.  The total amount of incident radiation received by  one specimen during the exposure was measured by a miniature camera to compare with that of other.specimens for the purpose of correction.  A radial photometer trace was then taken from  one of the exposed quadrants of the X-ray diagram. The integrated intensity of the crystalline interference above the background was considered as a measure of the crystalline fraction, whereas maximum intensity of the background scattering was used as a measure of the fraction of disordered cellulose.  A similar assumption was applied later by Kast and  Plaschner ( 3 1 , 6 9 ) , and Clark and Terford ( 1 9 ) . This method has been extensively applied by Hermans and his co-workers i n establishing absolute value of crystallinity for different types of cellulose ( 4 5 , 4 7 , 4 8 , 4 9 , 5 0 , 5 1 , 5 2 , 5 4 ) . Although Hermans' method gives an absolute value of crystallinity, i t does not necessarily mean that a l l crystalline regions are completely measured, because of the fact that very small crystalline regions w i l l not contribute to the X-ray maxima. Moreover, this method requires a special type of camera and a rotating sample holder, so that in most cases this method is not easily adopted for routine  24  purpose. may  A simple technique w i t h reasonable r e p r o d u c i b i l i t y  be much more p r a c t i c a l i n the case where only r e l a t i v e  v a r i a t i o n of c r y s t a l l i n i t y  i s of i n t e r e s t t o the  investigator.  S e v e r a l techniques have been developed during the l a s t few y e a r s .  These techniques g e n e r a l l y use X-ray  equipment which i s a v a i l a b l e c r y s t a l l i n i t y i s calculated  i n most l a b o r a t o r i e s .  by a simple formula which gives  r e l a t i v e r a t h e r than a b s o l u t e c r y s t a l l i n i t y . and C r y s t a l  The  (148) have demonstrated  Wakelin,  Virgin  an i n t e g r a t e d method and a  c o r r e l a t i o n method by u s i n g Geiger Counter i n s t r u m e n t a t i o n . The r e s u l t was  expressed as a c r y s t a l l i n i t y  index.  Ant-?/uorlnen (5>6)  developed another c r y s t a l l i n i t y index u s i n g  the Debye-Scherrer  powder t e c h n i q u e .  The width and h e i g h t ' o f  the 002 peak on the photometer i n t e n s i t y curve were used as a measure of c r y s t a l l i n i t y .  The technique was  K o u r i s , Ruck and Mason (72,73). spectrometer was The  illustrated  l a t e r improved  The a p p l i c a t i o n of an X-ray  by Anker-Rasch and McCarthy (3>4).  i n t e n s i t y of the 101 peak was  taken as a measure of  c r y s t a l l i n i t y and r e s u l t s were expressed as a ratio.  Ingersoll  (65)  c r y s t a l l i n i t y number.  crystallinity  a l s o used t h i s peak t o evaluate the Sobue and Minato  (133)  simply took the  area surrounded by the i n t e n s i t y curve ( i n c l u d i n g 002 peaks)" and background comparison  by  101, 101  and  curve as the c r y s t a l l i n i t y area f o r  of r e l a t i v e order of c r y s t a l l i n i t y .  25  ii)  Moisture regain method Hermans was the f i r s t to establish the r e l a t i o n s h i p  between the sorption r a t i o (SR) of c e l l u l o s e , and amorphous 2  content as estimated by the density or X-ray method ( 4 3 ) . The regression l i n e gave the equation: SR = 0 . 0 7 +  3 ( 1 - * * ) '  where cK was the f r a c t i o n of c r y s t a l l i n e material. the SR i s determined experimentally,  then the c r y s t a l l i n i t y  i s r e a d i l y calculated from the equation. equation,  Thus, i f  According  to this  the sorption r a t i o of completely amorphous c e l l u l o s e  is 3 . 0 7 . Howsmon (63) also showed that there was an approximately linear relationship between the sorption of c e l l u l o s e and a c c e s s i b i l i t y to l i q u i d  D2O-H2O  mixture.  Assuming that the moisture regain was a measure of a c c e s s i b i l i t y , and that Mark's value (35) f o r the a c c e s s i b i l i t y of cotton (0.44) was correct, Howsmon obtained the a c c e s s i b i l i t y of other c e l l u l o s e preparations  by multiplying t h e i r sorption  r a t i o by 0.44. Later, t h i s value was changed to 0.40 (110). The relationship between sorption r a t i o and the f r a c t i o n of amorphous materials, as measured by Mann and Marrinan ( 8 3 ) , was also i l l u s t r a t e d by Valentine  (147) with a regression equation  ^Sorption r a t i o (SR) i s the r a t i o of moisture sorption of a s p e c i f i c c e l l u l o s e to that of cotton under the same conditions (146). Since the sorption r a t i o i s independent of the temperature and r e l a t i v e humidity over the range of 20 to 70 percent (110), i t i s often convenient to use sorption r a t i o rather than absolute absorption.  26  SR. = 2.6 F , where F m  m  was the amorphous f r a c t i o n and SR was  the s o r p t i o n r a t i o . Magne, Portas and Wakeham (8l) c a l c u l a t e d the r e l a t i v e amount of f r o z e n water ( c a p i l l a r y condensed or solvent water) and unfrozen water (bound water) from c a l o r i m e t r i c data.  Assuming that three molecules of water  were absorbed by each glucose anhydride u n i t , he was able t o c a l c u l a t e the degree of c r y s t a l l i n i t y .  Recently, Preston  and Tawde (114) a l s o determined the bound water i n f i b r e s , and found a d i r e c t c o r r e l a t i o n between the bound-water r a t i o ( i . e . , the bound-water r e l a t i v e t o that of cotton) and the sorption r a t i o .  The bound-water r a t i o of hydrate c e l l u l o s e  (123), which they assumed t o be completely amorphous, may be c a l c u l a t e d from t h e i r data t o be 3»2> thus leading t o a s o r p t i o n r a t i o of the same value. Heat of wetting a l s o may be used as a measure of the amorphous f r a c t i o n of c e l l u l o s e because h i g h l y amorphous c e l l u l o s e always gives a high value of heat of wetting (15D. There i s a strong c o r r e l a t i o n between s o r p t i o n r a t i o and heat of w e t t i n g , i . e . , the higher the heat of w e t t i n g , the higher w i l l be the s o r p t i o n r a t i o , so that the a p p l i c a t i o n of heat of wetting f o r determination of c r y s t a l l i n i t y i s g e n e r a l l y replaced by the s o r p t i o n r a t i o or moisture r e g a i n method.  27  iii)  I n f r a - r e d a b s o r p t i o n spectroscopy  The spectroscopy  direct application  of i n f r a - r e d  method absorption  i n t o the f i e l d of c r y s t a l l i n i t y s t u d i e s  was  ignored u n t i l F o r z i a t i and Rowen ( 3 3 , 3 4 ) demonstrated spectra, of c o t t o n before and  after grinding i n a  the  vibrating'  b a l l m i l l . ~ They found t h a t the s p e c t r a of c e l l u l o s e  I  showed sharp and  c l e a r l y d e f i n e d a b s o r p t i o n bands a t  7.0>  7*3> 7'4  micron wave l e n g t h s .  and 7 . 5  i s converted vibrating  When the c e l l u l o s e I  i n t o amorphous m a t e r i a l by g r i n d i n g i n a  b a l l m i l l , these maximum a b s o r p t i o n bands merged  i n t o a s i n g l e broad band, and  the a b s o r p t i o n at 1.1;2  microns  increased. O'Connor, Dupre and Mitcham (108) f a c t and  took the r e l a t i v e change of o p t i c a l <|ensity of the  a b s o r p t i o n bands at 6.9 of c r y s t a l l i n i t y . The 11.0  microns and  maximum, a t a b o u t r  6.9  I l . O microns as measures  a b s o r p t i o n bands at 6.9  microns r e p r e s e n t e d  'band r e s p e c t i v e l y .  was  made use of t h i s  The  microns  and  c r y s t a l l i n e bands and an amorphous r a t i o of the absorbence of the band  microns, to t h a t at about 11.0  d e f i n e d as the c r y s t a l l i n i t y index.  The  microns,  assignment of a  c r y s t a l l i n e band to a p a r t i c u l a r wave l e n g t h i s dependent upon types  of c e l l u l o s e under q u e s t i o n .  (122), f o r example, a s s i g n e d  Sandeman and  a b s o r p t i o n bands at 10.7  Keller microns  i n the s p e c t r a of n y l o n 6,  at 10.67  of n y l o n 6 . 6 ,  microns i n the s p e c t r a of n y l o n  6.10,  and a t 10.64  as c r y s t a l l i n e bands.  microns i n the  For the wood-fibre  spectra  cellulose  28  prepared  from western hemlock, t h e w r i t e r found t h a t the  c r y s t a l l i n e band c o u l d be a s s i g n e d a t 7*2 microns and the amorphous band a t 11.2 microns.3  Sobue and Fukuhara  (132),  on the other hand, took the r a t i o of the o p t i c a l d e n s i t y a t a b s o r p t i o n caused by OH s t r e t c h i n g  (3315 cm."*-*- f o r ramie and  3440 cra.""^ f o r v i s c o s e r e s p e c t i v e l y ) , t o t h a t caused by CH s t r e t c h i n g a t 2900 cm.~^, as a measure of c r y s t a l l i n i t y . Iv)  D e n s i t y method For a g i v e n weight of f i b r e , t h e r e s u l t of a  d e n s i t y d e t e r m i n a t i o n w i l l depend on the extent t o which the medium p e n e t r a t e s i n t o the amorphous r e g i o n , which i s the only r e g i o n a l l o w i n g the molecules  of the medium t o p e n e t r a t e .  On t h i s b a s i s , i t i s l o g i c a l t o presume t h a t the d e n s i t y of packing o f f i b r o u s substance  p r o v i d e s a reasonable  criterion  f o r the q u a n t i t a t i v e s e p a r a t i o n o f t h e c r y s t a l l i n e and the amorphous p o r t i o n .  Hermans and h i s co-worker  (43,53)  estimated the a b s o l u t e q u a n t i t y of the c r y s t a l l i n e  substance  by assuming t h a t the d i f f e r e n c e between the s p e c i f i c volume o f the c r y s t a l l i n e substance,  and t h a t of the amorphous s t a t e ,  are of t h e same order f o r c e l l u l o s e as they a r e f o r other o r g a n i c substances.  The r e s u l t s were i n good agreement w i t h  other p h y s i c a l methods. I t was a l s o suggested  t h a t d e t e r m i n a t i o n of d r y  d e n s i t y , p o s s i b l y by the use of a d e n s i t y g r a d i e n t tube,  ^Unpublished  data.  should  29  provide a convenient  method f o r d e t e r m i n i n g  an approximate  value of the c r y s t a l l i n i t y of c e l l u l o s e f i b r e ( 9 2 ) . 3.  Treatments a f f e c t i n g  crystallinity  From.the-foregoing.description,  i t follows that  the c r y s t a l l i n i t i e s of various c e l l u l o s i c m a t e r i a l s are d i f f e r e n t f r o m one a n o t h e r , and t h e a b s o l u t e v a l u e o f c r y s t a l l i n i t y o f t h e same c e l l u l o s e i s a l s o v a r i a b l e depending on the method a p p l i e d .  Furthermore, the i n i t i a l  c r y s t a l l i n i t y o f c e l l u l o s e c a n be m o d i f i e d t o g i v e h i g h e r o r lower v a l u e s by v a r i o u s m e c h a n i c a l and chemical, t r e a t m e n t s . The purpose o f t h i s s e c t i o n i s t o d i s c u s s some major e f f e c t s of v a r i o u s t r e a t m e n t s  on c r y s t a l l i n i t y , and a l s o t h e i r  s i g n i f i c a n c e from t h e p o i n t o f view o f a p p l i c a t i o n t o the study of f i n e s t r u c t u r e of c e l l u l o s i c m a t e r i a l s . (a)  Hydrolysis M e l l e r ( 8 8 ) , I n g e r s o l l (65) > and Howsmon (63) have  shown t h a t t h e c r y s t a l l i n i t y o f c e l l u l o s e w i l l be c o n s i d e r a b l y increased after h y d r o l y s i s .  B o t h removal o f amorphous  m a t e r i a l by a c i d a t t a c k , and r e c r y s t a l l i z a t i o n o f c e l l u l o s e molecular  c h a i n s , a r e r e s p o n s i b l e f o r such an e f f e c t .  reason i s that molecular  The  c h a i n s i n t h e amorphous r e g i o n , o n c e  r u p t u r e d by a c i d a t t a c k , tend t o i n c r e a s e t h e m o b i l i t y o f t h e c h a i n end and a l l o w them t o r e a r r a n g e more compact f o r m .  themselves i n a much  The i n c r e a s e i n c r y s t a l l i n i t y by  h y d r o l y s i s can be shown c l e a r l y by X - r a y diagrams i n w h i c h  30  the i n t e n s i t y of the 002 peak and the 101 + 101 combination peak w i l l i n c r e a s e markedly  after  hydrolysis.  The f a c t t h a t the r u p t u r e of the c h a i n s t a r t s  from  the amorphous r e g i o n can be observed from the r e a c t i o n - r a t e curve of h y d r o l y s i s .  During the i n i t i a l  stage of r e a c t i o n ,  the chemical reagents p e n e t r a t e r a p i d l y i n t o the amorphous region.  Most o f the r u p t u r e of the chains takes p l a c e a t  t h i s stage, thus the r e a c t i o n proceeds a t a very r a p i d  rate.  As soon as the amorphous r e g i o n has been d e s t r o y e d , the r e a c t i o n w i l l be slowed down because  the chemical reagent  does n o t r e a d i l y p e n e t r a t e i n t o the c r y s t a l l i n e r e g i o n , but merely a t t a c k s the s u r f a c e of the c r y s t a l l i t e .  Consequently,  the s i z e of the c r y s t a l l i t e w i l l g r a d u a l l y decrease as the time o f h y d r o l y s i s i s prolonged ( 6 4 , 1 1 ) .  The percentage of  r e s i d u e r e c o v e r e d w i l l decrease p r o p o r t i o n a l l y w i t h time of h y d r o l y s i s , but the c r y s t a l l i n i t y significantly.  of r e s i d u e w i l l i n c r e a s e  The r a t e o f i n c r e a s e i n c r y s t a l l i n i t y  h y d r o l y s i s f o l l o w s a curve s i m i l a r t o the h y d r o l y s i s curve.  rate  The h y d r o l y s i s method i s g e n e r a l l y used t o prepare a  c e l l u l o s e standard of h i g h c r y s t a l l i n i t y (b)  due t o  (83,87,148).  Heat I f the c e l l u l o s e i s d r i e d under heat without a  prolonged d r y i n g time, i t s c r y s t a l l i n i t y l e s s e r extent.  For i n s t a n c e , very l i t t l e  i s affected to a change i n chemical  nature takes p l a c e when c e l l u l o s e i s heated a t a  temperature  31  of 140°C f o r l e s s than f o u r hours (32,39,62,119)  (28).  I t has been shown  t h a t a t a s u f f i c i e n t l y h i g h temperature,  c e l l u l o s e undergoes  both chemical and p h y s i c a l m o d i f i c a t i o n s  and the molecular c h a i n s w i l l be d i s o r d e r e d due t o a thermal effect. H e s s l e r and Power (59) observed that s u r f a c e heat was more e f f e c t i v e i n opening the c r y s t a l l i t e than hot a i r . Cotton r o t a t e d a g a i n s t a hot s u r f a c e f o r a few minutes showed a drop i n c r y s t a l l i n i t y from 89 percent t o 79 percent as determined by the i o d i n e s o r p t i o n method.  T a n i g u c h i (143)  claimed t h a t c r y s t a l l i n i t y of s u l p h i t e pulp decreased on h e a t i n g w i t h hot a i r f o r 1 t o 2 hours a t 110 t o 245°C.  The  decrease was p a r t i c u l a r l y remarkable as the temperature was increased. (c)  Mechanical  decrystallization  G r i n d i n g and v i b r a t i n g appreciable d e c r y s t a l l i z a t i o n  i n a b a l l m i l l w i l l cause an  (33,34,45,58,72,94,108,136,137).  In t h i s case f i b r e s a r e d i s i n t e g r a t e d i n t o very f i n e powder which does not show s e l e c t i v e  d i f f r a c t i o n on an X-ray  diagram, but Increases the background amorphous p a r t i c l e s  (72,110).  s c a t t e r i n g caused by  I n the i n f r a - r e d a b s o r p t i o n  spectrum, t h i s f i n e powder w i l l show an i n c r e a s e d a b s o r p t i o n at the amorphous band and decreased a b s o r p t i o n at the c r y s t a l l i n e band ( 3 4 , 1 0 8 ) .  32  The mechanism f o r t h i s type o f d e g r a d a t i o n c a n be e x p l a i n e d from t h e p o i n t o f view o f m e c h a n i c a l impact and stress cycling.  I f t h e k i n e t i c energy produced by t h e impact  o f t h e b a l l s on t h e c e l l u l o s e f i b r e s i s c o n v e r t e d d i r e c t l y i n t o m o l e c u l a r v i b r a t i o n a l energy, i t i s s u f f i c i e n t t o cause r u p t u r e o f t h e p r i m a r y v a l e n c e bonds (137)•  The impact o f t h e  b a l l s on t h e c o n t a i n e r e v o l v e s a c o n s i d e r a b l e amount o f h e a t . By means o f t h e Congo r e d t e s t , i t was shown t h a t t h e r u p t u r e o f t h e c e l l u l o s e c h a i n was t h e r e s u l t o f m e c h a n i c a l a c t i o n r a t h e r t h a n a t h e r m a l phenomenon (110,137)*  Mechanical  d e c r y s t a l l i z a t i o n i s commonly used f o r t h e p r e p a r a t i o n o f an amorphous s t a n d a r d i n t h e X - r a y method as w e l l as i n t h e i n f r a r e d a b s o r p t i o n s p e c t r o s c o p y method. (d)  D e g r a d a t i o n by microorganisms Decay o f c e l l u l o s i c m a t e r i a l i s a t t r i b u t e d t o t h e  enzymes w h i c h a r e s e c r e t e d by m i c r o o r g a n i s m s .  The amorphous  r e g i o n s a r e l o o s e l y compacted and r e a d i l y a v a i l a b l e f o r p e n e t r a t i o n o f enzymes, w h i c h , l i k e o t h e r c h e m i c a l r e a g e n t s , a t t a c k t h e amorphous r e g i o n s a t a r e l a t i v e l y r a p i d r a t e i n t h e i n i t i a l s t a g e o f decay.  The r a t e o f a t t a c k w i l l slow r a p i d l y  when t h e enzymes s t a r t t o a t t a c k t h e c r y s t a l l i n e r e g i o n s . As a r e s u l t o f such a t t a c k , t h e amorphous m a t e r i a l s a r e d i s s o l v e d away and t h e b r o k e n c h a i n s themselves t e n d t o recrystallize.  Hence, d u r i n g t h e i n c i p i e n t stage o f decay, an  a p p r e c i a b l e i n c r e a s e i n c r y s t a l l i n i t y c o u l d be e x p e c t e d .  The  33 r a t e o f i n c r e a s e i n c r y s t a l l i n i t y i s approximately a f u n c t i o n of r a t e o f breakdown of c e l l u l o s e chains 131).  by enzymes ( 1 1 0 ,  The r a t e curve i s s i m i l a r t o that of a c i d h y d r o l y s i s .  I t should  be noted, however, t h a t the a c t i o n o f microorganisms  i s s l i g h t l y d i f f e r e n t from that of a c i d h y d r o l y s i s i n t h a t the former does not decrease the degree o f p o l y m e r i z a t i o n ( 1 1 0 , 1 5 1 ) , whereas the l a t t e r markedly depolymerizes the c e l l u l o s e chains  (26,163).  Some workers c l a i m that  h y d r o l y s i s w i l l a l s o cause c o n s i d e r a b l e (30,41,61,76,106,107,159). this (e)  enzymatic  depolymerization  Thus a c o n t r o v e r s y  still  e x i s t s on  point. Lattice transition 1)  T r a n s i t i o n from c e l l u l o s e I t o c e l l u l o s e I I When n a t i v e c e l l u l o s e i s t r e a t e d w i t h a c e r t a i n  concentration  of sodium hydroxide ( m e r c e r i z a t i o n ) , the  l a t t i c e s t r u c t u r e i s changed and c e l l u l o s e I I i s formed. Treatment w i t h about 6 l percent  n i t r i c a c i d f o l l o w e d by  washing a l s o r e s u l t s i n the same t r a n s i t i o n ( 2 ) .  This  t r a n s i t i o n changes n o t only the dimensions of the l a t t i c e u n i t c e l l as r e v e a l e d  on the X-ray d i f f r a c t i o n p a t t e r n , but a l s o  the degree of c r y s t a l l i n i t y o f c e l l u l o s e , which w i l l be decreased due t o m e r c e r i z a t i o n  (3>54).  T h i s i s caused mainly  by the d i s o r d e r i n g of the c e l l u l o s e molecular chains by the p e n e t r a t i o n l a t t i c e during  produced  of sodium hydroxide molecules i n t o the  the m e r c e r i z a t i o n , w i t h the r e s u l t that the  34  amorphous r e g i o n i n c r e a s e s a t the expense of the c r y s t a l l i n e region. Anker-Rasch and McCarthy (3) made use of t h i s c h a r a c t e r i s t i c t o study the c o n c e n t r a t i o n of sodium hydroxide a t which the l a t t i c e t r a n s i t i o n was completed, by f o l l o w i n g the v a r i a t i o n of c r y s t a l l i n i t y . When the t r a n s i t i o n took p l a c e , the c r y s t a l l i n i t y decreased r a p i d l y .  Higgins (60)  a l s o s t u d i e d the l a t t i c e t r a n s i t i o n by i n f r a - r e d a b s o r p t i o n spectroscopy and found t h a t when l a t t i c e t r a n s i t i o n took p l a c e , the absorbency a t 7.0 microns decreased, and t h a t a t 11.2  microns i n c r e a s e d .  S i n c e the c r y s t a l l i n i t y decreases a t  t h i s p o i n t , the r e l a t i v e absorbency  a t these two wave l e n g t h s  c o u l d be taken as the measure o f c r y s t a l l i n i t y . T h i s g i v e s additional  evidence t h a t the assignment  o f a c r y s t a l l i n e band  at about 7'0 microns and an amorphous band a t about  11.2  4  microns i s a c c e p t a b l e . ii)  Transition  from c e l l u l o s e I t o c e l l u l o s e I I I  On treatment of c e l l u l o s e I w i t h ethylamine, c e l l u l o s e I I I i s obtained.  A decrease i n c r y s t a l l i n i t y i s  inevitable  because  of the i n t r a c r y s t a l l i n e s w e l l i n g due t o  ethylamine  (9,18,78,79,128,129).  A h i g h l y amorphous c e l l u l o s e ,  t h e r e f o r e , can be o b t a i n e d by t r e a t i n g  c e l l u l o s e with  ethylamine f o l l o w e d by e v a p o r a t i o n of the amine a t atmospheric  'See page 28.  35  pressure.  T h i s i s sometimes done i n order t o prepare an  amorphous standard f o r the study of c r y s t a l l i n i t y iii)  (108,148).  T r a n s i t i o n from c e l l u l o s e I I and I I I t o c e l l u l o s e IV  When c e l l u l o s e I I or c e l l u l o s e I I I i s heated a t temperatures  between 140 t o 300°C i n water under p r e s s u r e , i n  g l y c e r o l , or i n formamide, c e l l u l o s e IV i s formed The  (75»9D•  c r y s t a l l i n i t y o f c e l l u l o s e IV i s s i g n i f i c a n t l y h i g h e r  than t h a t o f c e l l u l o s e I I or c e l l u l o s e I I I . (f)  Pulping The e f f e c t o f p u l p i n g on c r y s t a l l i n i t y of pulp was  w e l l demonstrated by T a n i g u c h i ' s s e r i e s o f experiments. F o l l o w i n g the curve o f changes i n c r y s t a l l i n e r e g i o n s d u r i n g sulphate p u l p i n g , he found t h a t the c r y s t a l l i n e r e g i o n content of bleached pulp and v i s c o s i t y decreased r a t e o f decomposition time  (141).  g r a d u a l l y , and the  i n c r e a s e d w i t h the l e n g t h of p u l p i n g  The sulphate pulp was bleached by 2 - , 3~» 9- d 5n  stage methods and the c r y s t a l l i n i t y as determined  by the  h y d r o l y s i s method was found t o be 9l«60, 92.45, and 92.63 percent r e s p e c t i v e l y  (138).  However, n e g l i g i b l e d i f f e r e n c e s i n  c r y s t a l l i n i t y o f pulp bleached by NaC102 and C a ( C 1 0 ) observed  i n h i s l a t e r works (139,140).  2  were  He a l s o showed t h a t  the c r y s t a l l i n i t y of s u l p h i t e pulp i n c r e a s e d on h e a t i n g w i t h water f o r two hours a t 100 t o 190°C, but decreased w i t h h o t a i r f o r 1 t o 2 hours a t 110 t o 245°C.  on h e a t i n g  The r a t e of  36  decrease i n c r y s t a l l i n i t y The  i n c r e a s e d w i t h temperature  (143).  e f f e c t of b e a t i n g on c r y s t a l l i n i t y was observed by  Wijnman ( l 6 o ) .  He claimed  t h a t when p u r i f i e d c o t t o n  fibres  were s ub jected t o heavy b e a t i n g i n a Jokro m i l l , a marked decrease was observed i n the degree of p o l y m e r i z a t i o n ,  together  w i t h a moderate r e d u c t i o n i n the average s i z e of c r y s t a l l i t e and  a small reduction i n c r y s t a l l i n i t y .  Groundwood pulp was  found t o g i v e h i g h c a p a c i t y of s u l f u r i c  a c i d s o r p t i o n (117)»  which i n d i c a t e s t h a t the groundwood pulp might have a relatively (g)  h i g h value o f  accessibility.  Stretching S t r e t c h i n g u s u a l l y causes an i n c r e a s e i n  crystallinity. coagulated and  For i n s t a n c e , i t was estimated  v i s c o s e f i l a m e n t was about 40 percent  60 percent  crystalline  s t r e t c h e d , appeared t o be 70 percent  and 30 percent  amorphous (100).  R e l a t i o n s h i p between c r y s t a l l i n i t y of  crystalline  amorphous, whereas f i l a m e n t s o f the same  m a t e r i a l a f t e r being  4.  t h a t a normal  and p r o p e r t i e s  cellulose The r e l a t i o n s h i p between c r y s t a l l i n i t y  reactivity,  and chemical  d e n s i t y , moisture r e g a i n , and dye s o r p t i o n i n  terms of i o d i n e s o r p t i o n have been d e s c r i b e d i n d e t a i l . present  The  d i s c u s s i o n i s c o n f i n e d t o the r e l a t i o n s h i p between  c r y s t a l l i n i t y and remaining  p r o p e r t i e s of c e l l u l o s e .  37  (a)  Young's modulus I t has been p o i n t e d o u t by Mark ( l 6 l ) t h a t  u n c r y s t a l l i z e d and p o o r l y o r g a n i z e d c h a i n s w i l l e x h i b i t e l a s t i c i t y o f t h e type w h i c h has been r e c e n t l y i n v e s t i g a t e d i n h i g h l y e l a s t i c long polymers.  Measurements and,  c a l c u l a t i o n s o f v a r i o u s workers ( l 6 l ) a l s o showed t h a t t h e presence o f l o n g f l e x i b l e c h a i n s l e d t o a r e v e r s i b l e f.  e l a s t i c i t y , w i t h modulus o f about 10  7  t o 10' dynes p e r s q . cm.  and a r a t h e r h i g h range o f e x t e n s i b i l i t y .  On t h e o t h e r hand,  i f a f o r c e i s a p p l i e d t o a homopolar c o v a l e n t bond and t h e a s s u m p t i o n i s made t h a t t h e sample under i n v e s t i g a t i o n i s made up o f i n f i n i t e l y l o n g , u n i n t e r r u p t e d , p a r a l l e l c h a i n s , a IP  modulus o f e l a s t i c i t y i s o b t a i n e d of. about 2 x 10 s q . cm.  T h i s would c o r r e s p o n d  t o a completely  c  dynes p e r  crystallized  and p e r f e c t l y o r i e n t e d m a t e r i a l . C e l l u l o s e c a n be c o n s i d e r e d as a m i x t u r e o f c r y s t a l l i z e d and amorphous r e g i o n s i n w h i c h t h e former have an average e l a s t i c modulus o f about 1 0 ^ , whereas t h e l a t t e r have one  o f about 10^ dynes p e r s q . cm. ( l 6 l ) .  Applying  this  i d e a , Hermans and co-workers (44), and o t h e r s  (85),  the l o n g - r a n g e ,  o f c e l l u l o s e by  two m o d u l i .  low-modulus, e l a s t i c b e h a v i o r  explained  The one w h i c h corresponded t o t h e c r y s t a l l i n e  p a r t s had t h e o r d e r o f magnitude o f 1 0  X A  t o 10^  dynes, and  t h e one w h i c h c o r r e s p o n d e d t o t h e amorphous r e g i o n had an o r d e r o f 10^ t o 10? dynes p e r s q . cm.  I n s h o r t , from t h e  p o i n t o f view o f a c h a i n model, h i g h modulus i s t h e o r e t i c a l l y  38  understood to be a s s o c i a t e d w i t h a h i g h degree of crystallinity. (b)  Tensile strength I f i t i s assumed t h a t a sample c o n s i s t s of  uninterrupted p a r a l l e l g l u c o s i d i c chains, a t h e o r e t i c a l t e n a c i t y of about (10).  400,000  kg. per sq. cm.  In the case of completely  c h a i n s , having  parallel,  expected  overlapping  an average degree of p o l y m e r i z a t i o n of  glucose u n i t s , t h i s value has per sq. cm.  c o u l d be  (10,90).  been c a l c u l a t e d to be  $00  12,500 kg. /  From the t h e o r e t i c a l p o i n t of view, the  c r y s t a l l i t e forms the f i r m r e i n f o r c i n g p a r t of the s t r u c t u r e , whereas the amorphous r e g i o n s are the a c t u a l p o i n t s of weakness (100).  I t f o l l o w s t h a t c e l l u l o s e of h i g h  c r y s t a l l i n i t y u s u a l l y has h i g h t e n s i l e  strength.  On the other hand, both the o r i e n t a t i o n of m i c e l l e s and  c e l l u l o s e c h a i n l e n g t h d i s t r i b u t i o n are a l s o found to be  important  factors a f f e c t i n g t e n s i l e strength  109,ll8,135»l58). complicated  The  t h a t one  i n t e r a c t i o n s among these f a c t o r s are  has  no  t e n s i l e strength alone.  Ingersoll  shown by a p a r t i a l l i n e a r c o r r e l a t i o n technique  at a constant wet  so  can h a r d l y e s t a b l i s h a r e l a t i o n s h i p  between c r y s t a l l i n i t y and (65)  (14,21,29,56,86,  e l o n g a t i o n and  o r i e n t a t i o n , wet  tenacity i s  longer s i g n i f i c a n t l y a s s o c i a t e d w i t h l a t e r a l o r d e r .  the degree of c r y s t a l l i n i t y alone might not be a f a c t o r which a f f e c t s the t e n s i l e  strength.  that  Thus,  critical  39  (c)  Elongation Mark (85)  has  proposed t h a t f l e x i b i l i t y  r e a c t i v i t y of c e l l u l o s e are dependent upon the r e g i o n of c e l l u l o s e , whereas the t e n a c i t y and modulus are r e l a t e d t o the amount of ordered T h i s i s confirmed Ward (151)  by v a r i o u s experimental  and  disordered elastic  materials.  data.  demonstrated t h a t yarns from cottons  For of  example, decreased  c r y s t a l l i n i t y d i d have i n c r e a s e d e l o n g a t i o n as compared w i t h t h a t of the o r i g i n a l c o t t o n .  Conrad and Scroggie  that e l o n g a t i o n i n c r e a s e d w i t h a c c e s s i b i l i t y r e s u l t s were obtained  by I n g e r s o l l ( 6 5 ) ,  when o r i e n t a t i o n and wet  a l s o found  (22).  who  Similar  claimed  t e n a c i t y were kept constant  that by  the  method of p a r t i a l l i n e a r c o r r e l a t i o n , the r e l a t i o n s h i p between wet  e l o n g a t i o n and  l a t e r a l order remained  statistically  significant. (d)  A l p h a - c e l l u l o s e content Conrad and Scroggie  (22) demonstrated t h a t a  decrease i n a c c e s s i b i l i t y or an i n c r e a s e i n c r y s t a l l i n i t y , i n g e n e r a l , was content may  p a r a l l e l e d by an i n c r e a s e i n a l p h a - c e l l u l o s e  of the raw  material.  The  decrease i n a c c e s s i b i l i t y  a r i s e from somewhat s m a l l e r amounts of r e l a t i v e l y  molecular-weight m a t e r i a l s such as beta and i n the h i g h - a l p h a - c e l l u l o s e m a t e r i a l . results  low-  gamma c e l l u l o s e  Actual  experimental  (22) showed t h a t x y l o s e and pentosan evolved C 0  r,ate h i g h e r than c e l l u l o s e or even g l u c o s e .  An  2  at a  increase i n  40  a c c e s s i b i l i t y should t h e r e f o r e occur when m a t e r i a l s of t h i s type are p r e s e n t . cellulose  The  g e n e r a l r e l a t i o n between a l p h a -  content and c r y s t a l l i n i t y i s shown i n Table  T a b l e 2.  R e l a t i o n s h i p between a l p h a - c e l l u l o s e and c r y s t a l l i n i t y of c e l l u l o s e (22)  Alpha-cellulose content (%)  Source  Wood pulp from beech Wood pulp from southern pine Wood pulp from western hemlock High-alpha wood pulp from southern p i n e Cotton l i n t e r s  content  Accessibility* (%)  - 89.0  88.5 93.P  2.  H.5 10.0  9.0  91.5  - 95.0  94.5 98.5  7.5 5.3  •Determined by a c i d h y d r o l y s i s method  (e)  S w e l l i n g and dimensional s t a b i l i t y As f a r as s w e l l i n g due t o water i s concerned,  be c o n s i d e r e d as the f i n a l r e s u l t molecules  i n t o the c e l l u l o s e  of p e n e t r a t i o n of water  inter-molecular chain region,  which, i n t u r n , causes an expansion p e n e t r a t e between two molecule energy  cellulose  or to break the secondary  i n volume.  I n order to  molecular c h a i n s , a water  should have enough energy  molecular c h a i n s .  to overcome the l a t t i c e  bonds between  T h i s can be done e a s i l y  cellulose  i n amorphous  r e g i o n s or on the s u r f a c e of c r y s t a l l i t e s .where the m o l e c u l a r c h a i n bondings are weak, but not i n the region.  i t can  intercrystalline  T h e r e f o r e , i t i s reasonable t o expect that s w e l l i n g  41  w i l l decrease as the c r y s t a l l i n i t y  i s increased.  T h i s i s confirmed by the f a c t t h a t s w e l l i n g decreases as f i b r e d e n s i t y i n c r e a s e s . which s w e l l s 160  percent  For example, a rayon  of i t s i n i t i a l volume has  a density  of 1 . 5 0 3 , whereas c o t t o n which s w e l l s only 50 percent d e n s i t y of 1.534  (100).  has  a  I t should be reemphasized t h a t both  degree of c r y s t a l l i n i t y and  s i z e of c r y s t a l l i t e p l a y  e q u a l l y important r o l e i n the a b s o r p t i o n  of moisture  an and  s w e l l i n g of c e l l u l o s e . Based on the c h a r a c t e r i s t i c nature of the amorphous and  the c r y s t a l l i n e r e g i o n so f a r d i s c u s s e d , the r e s u l t s  shown i n Table  3  be expected i f the degree of  crystallinity  of c e l l u l o s e i s i n c r e a s e d .  T a b l e 3•  Variation i n cellulose properties c r y s t a l l i n i t y increases (110)  Increase density Young's modulus t e n s i l e strength a l p h a - c e l l u l o s e content dimensional s t a b i l i t y hardness  as  Decrease moisture r e g a i n dye s o r p t i o n chemical r e a c t i v i t y swelling elongation flexibility toughness  EXPERIMENTAL METHOD A.  Materials The study c o n s i s t s of t h r e e p a r t s , as f o l l o w s :  Part  I:  C r y s t a l l i n i t y of normal wood of v a r i o u s ages and seasons, i . e . , summerwood and springwood.  Part  I I . C r y s t a l l i n i t y of r e a c t i o n wood (compression wood and t e n s i o n wood.  P a r t I I I : C r y s t a l l i n i t y o f decayed wood. For  p a r t I , a c r o s s - s e c t i o n d i s c was taken from a  33-year o l d t r e e of western hemlock (Tsuga h e t e r o p h y l l a (Raf.) Sarg.) a t . a h e i g h t t e n f e e t above ground.  Several  s m a l l sample b l o c k s were prepared from the 3 r d , 9 t h , 1 5 t h and 21st the  growth r i n g from the p i t h at. randomized p o s i t i o n s w i t h i n r i n g , and separated w i t h a c h i s e l i n t o springwood and  summerwood.  The innermost p o r t i o n (about 1 mm. t h i c k ) of  each r i n g was taken as the springwood sample and the outmost p o r t i o n (about 1 mm. summerwood.  t h i c k ) of each r i n g was taken t o r e p r e s e n t  M i c r o s c o p i c examination showed that the summer-  wood sample c o n t a i n e d about 50 percent of springwood  trachelds.  A f i b r e was considered as a springwood t r a c h e i d i f the r a d i a l width of i t s c e l l lumen exceeded twice the c e l l w a l l thickness. The compression wood used i n p a r t I I was o b t a i n e d from an ^0-year o l d Douglas f i r (Pseudotsuga m e n z e i s i i (Mirb.)  43  Franco). 18th the  The compression wood sample  i n c l u d e d the 1 5 t h t o  growth r i n g s , whereas the normal wood sample taken from d i a m e t r i c a l l y opposed p o s i t i o n , i n c l u d e d from the 1 3 t h  to 21st growth r i n g s from the. p i t h , which gave the same average age i n both c a s e s .  For the t e n s i o n wood sample, a  l e a n i n g 28-year o l d n o r t h e r n b l a c k cottonwood t r i c h o c a r p a T o r r . and Gray) was sampled.  (Populus  T e n s i o n and normal  wood samples taken a t b r e a s t h e i g h t on o p p o s i t e s i d e s were of the  same age, i . e . , 20th t o 24th years from the p i t h . The decayed wood specimens used i n P a r t I I I were  o b t a i n e d by t r e a t i n g sample b l o c k s matched t o those used i n P a r t I I w i t h two brown-rot organisms, P o r i a i n c r a s s a t a and Poria monticola.  Treatment which caused about 6 p e r c e n t  weight l o s s due t o P o r i a i n c r a s s a t a was d e s i g n a t e d as stage A, whereas t h a t which r e s u l t e d i n 15 percent weight l o s s due t o P o r i a m o n t i c o l a was d e s i g n a t e d as stage B. B.  S t a t i s t i c a l design In p a r t I , two f a c t o r s were i n v o l v e d .  F a c t o r A:  Four d i f f e r e n t ages, i . e . , the 3 r d , 9 t h , 1 5 t h and 21st  F a c t o r B:  growth r i n g from the p i t h .  springwood  vs, summerwood.  S i n c e the summerwood sample c o n t a i n e d about 50 percent of springwood t r a c h e i d s , which might have obscured the  differences existing i n c r y s t a l l i n i t y  between springwood  and summerwood, the comparison of d i f f e r e n c e s w i t h i n f a c t o r B  44  required high efficiency.  Therefore, a s p l i t plot design  was a p p l i e d i n w h i c h f a c t o r A was a s s i g n e d as t h e u n i t , w h i l e f a c t o r B was a s s i g n e d as t h e sub-.urii.t w i t h t h r e e r e p l i c a t i o n s f o r X - r a y system A (wood p u l p ) and two r e p l i c a t i o n s f o r X - r a y system B ( h o l o c e l l u l o s e ) . I n p a r t I I , b o t h X - r a y method A (wood p u l p ) and X - r a y method B ( h o l o c e l l u l o s e ) were used as a randomized b l o c k d e s i g n , w i t h t h r e e r e p l i c a t i o n s f o r t h e former and two. f o r the l a t t e r , r e s p e c t i v e l y . A s p l i t p l o t d e s i g n was a l s o a p p l i e d i n p a r t I I I , i n o r d e r t o i n c r e a s e t h e e f f i c i e n c y f o r comparison o f d i f f e r e n c e s w i t h i n treatment e f f e c t s . Unit:  Thus:  Four t y p e s o f wood, i . e . , cottonwood t e n s i o n wood, cottonwood normal wood, Douglas f i r c o m p r e s s i o n wood and Douglas f i r normal wood.  Sub-unit:  Degree o f decay, i . e . , stage A ( a p p r o x i m a t e l y 6  p e r c e n t w e i g h t l o s s ) , s t a g e B ( a p p r o x i m a t e l y 15 p e r c e n t weight l o s s ) and c o n t r o l . Two r e p l i c a t i o n s were found t o be s u f f i c i e n t t o show d i f f e r e n c e s e x i s t i n g among t y p e s o f wood and degree o f decay. C.  P r e p a r a t i o n o f samples Wood p u l p and h o l o c e l l u l o s e samples were p r e p a r e d  f o r p a r t s I and I I o f t h i s s t u d y , whereas o n l y h o l o c e l l u l o s e was used f o r p a r t I I I .  The former was used t o p r e p a r e a  c y l i n d e r - t y p e specimen f o r X - r a y method A, w h i l e h o l o c e l l u l o s e  45  was used t o p r e p a r e a d i s c - t y p e specimen f o r X-ray method B. P r o c e d u r e s f o r p r e p a r a t i o n o f t h e s e samples a r e g i v e n below. 1.  Wood p u l p sample The sample b l o c k s were s p l i t a l o n g t h e g r a i n i n t o  s m a l l p i e c e s , p l a c e d i n t e s t tubes and b o i l e d i n water f o r eight hours.  The c h i p s were t h e n t r e a t e d w i t h a s o l u t i o n  c o n t a i n i n g e q u a l p a r t s o f 99»5 p e r c e n t a c e t i c a c i d and 30-35 p e r c e n t hydrogen p e r o x i d e .  The tubes were submerged i n a h o t  water b a t h and h e a t e d a t 100°C. f o r one hour.  The samples  were t h e n washed w i t h s e v e r a l runs o f water and shaken individual fibres.  into  The p u l p thus o b t a i n e d was t h o r o u g h l y  washed w i t h water f o r s e v e r a l d a y s , t o remove t h e l a s t t r a c e of a c i d , and f i n a l l y d r i e d a t 50°C. A c y l i n d e r - t y p e specimen, 15 mm. i n l e n g t h and 2 mm. i n diameter, was p r e p a r e d f o r X - r a y exposure.  To p r e p a r e such  a specimen, i t was n e c e s s a r y t o s e p a r a t e t h e a i r - d r i e d p u l p i n t o i n d i v i d u a l f i b r e s by a n e e d l e , i n o r d e r t o e l i m i n a t e t h e e f f e c t o f f i b r e o r i e n t a t i o n on X-ray d i f f r a c t i o n  (3,46,65,72).  E x a c t l y 50 mg. o f s e p a r a t e d f i b r e s were weighed and w e t t e d w i t h d i s t i l l e d water.  The f i b r e s were p u t i n t o a g l a s s tube  w i t h an i n n e r diameter o f 2 mm.  A s l i g h t p r e s s u r e was a p p l i e d  u n t i l t h e l e n g t h o f t h e specimen was reduced t o 15 mm. tube c o n t a i n i n g t h e specimen was t h e n d r i e d a t 50°C.  The After  two d a y s , t h e specimen was pushed from t h e tube and d r i e d i n the  open a i r .  The specimen thus p r e p a r e d was p e r f e c t l y  46  c y l i n d r i c a l and smooth; otherwise i t was r e j e c t e d . 2.  Holocellulose Wood meal was obtained by g r i n d i n g the sample  b l o c k s w i t h a Wiley m i l l .  S i n c e c r y s t a l l i n i t y w i l l decrease  i f the s i z e of p a r t i c l e i s too s m a l l , o n l y the f r a c t i o n  which  passed through a 20 mesh, and was r e t a i n e d on a 35 mesh s i e v e , was c o l l e c t e d . A m o d i f i c a t i o n of the c h l o r i t e method o f Wise,. Murphy and D'Addieco  (162),  suggested by Dr. A.P. Yundt,^ was  used f o r p r e p a r a t i o n of h o l o c e l l u l o s e . summarized b r i e f l y as f o l l o w s .  The procedure can be  To 0 . 7 g. of a i r - d r i e d wood  meal i n an Erlenmeyer f l a s k o f 60 ml. c a p a c i t y , were added 10 ml. of stock s o l u t i o n "A" c o n t a i n i n g 60 g. of a c e t i c and 20 g. of sodium hydroxide per l i t e r ,  acid  and 1 ml. o f stock  s o l u t i o n "B" c o n t a i n i n g 200 g. of sodium c h l o r i t e per l i t e r . The mixture was w e l l s t i r r e d and heated i n a hot water bath a t 75°C. the  After  .75, 1.5,  and 2 . 5 hours, an a d d i t i o n a l 1 ml. of  s t o c k s o l u t i o n "B" was added w i t h s t i r r i n g .  h e a t i n g , the f l a s k was c o o l e d i n i c e water. ice  A f t e r 4 hours  Then 15 ml. of  water was added, and the s o l u t i o n was removed by f i l t r a t i o n  through m i l d s u c t i o n .  The r e s i d u e was washed w i t h 100 ml. of  one percent a c e t i c a c i d s o l u t i o n , f o l l o w e d by two 5 nil* p o r t i o n s of acetone, and d r i e d i n the open a i r .  ^ P e r s o n a l correspondence w i t h Mr. J.M.  Jaworsky.  47  One hundred and f i f t y mg. of the a i r - d r i e d h o l l o c e l l u l o s e were put i n t o a s p e c i a l l y designed  compression  tube, and a gauge p r e s s u r e of 1000 p s i was a p p l i e d f o r f i v e minutes, using a l a b o r a t o r y p r e s s . specimen had a diameter approximately  The f i n a l d i s c - t y p e  of 14 mm. and a t h i c k n e s s of  0 . 7 5 mm.  D.  X-ray c o l l i m a t i n g system and procedure  1.  Method A The p r i n c i p l e of the Debye-Scherrer powder  was  a p p l i e d , as i l l u s t r a t e d i n F i g u r e 2, page 48.  technique  This  technique has been a p p l i e d by Ant-Wuorinen (5) f o r d e t e r m i n a t i o n of the c r y s t a l l i n i t y o f c e l l u l o s e .  The Cu K  o  alpha r a y having a wave l e n g t h o f 1.54 A was monochromized by a n i c k e l f i l t e r and passed  through a c o l l i m a t o r . When t h i s  i n c i d e n t r a y s t r i k e s the specimen r o t a t i n g a t one rpm, i t produces symmetrical  i n t e r f e r e n c e r i n g s on the f i l m .  The  specimen was s e t e x a c t l y a t the center o f the camera so t h a t a maximum, constant amount of f i b r e s were exposed t o the X-ray. In order t o c r e a t e an unexposed a r e a , the f i l m was covered w i t h a p i e c e o f l e a d f o i l a t the i n l e t bottom o f the collimator.  T h i s unexposed area g i v e s a zero r e a d i n g f o r the  densitometer  c a l i b r a t i o n t o be d e s c r i b e d l a t e r .  A P h i l i p s X-ray machine (No. 12045) was operated a t a v o l t a g e o f 45 k i l o v o l t s and c u r r e n t d e n s i t y o f 15 m i l l i a m p e r e s . The machine was allowed t o warm up f o r 30 minutes p r i o r t o  il-8  FIGURE  2.  CAMERA  ARRANGEMENT  POWDER  TECHNIQUE  30 | _ O  FIGURE  10 T 3.  \  EFFECT  FOR T H E  , 20 M E OF  (  X-RAY  CRYSTALLINITY  DEBYE-SCHERRER  , 30 M I  r-  40 N  )  EXPOSURE  INDEX  TIME  ON  49  introducing the f i r s t  sample.  I n order t o determine the  optimum e x p o s u r e t i m e , a p r e l i m i n a r y e x p e r i m e n t was out.  The r e s u l t s  shown i n F i g u r e 3 , p a g e 4 8 ,  optimum e x p o s u r e t i m e o f 20 m i n u t e s . X - r a y f i l m was u s e d . d e v e l o p e r D-19  i n d i c a t e an  Kodak m e d i c a l s a f e t y  The f i l m was d e v e l o p e d b y K o d a k X - r a y  f o r 5 m i n u t e s , f i x e d i n Kodak f i x e r  m i n u t e s , a n d h u n g up f o r d r y i n g . o b t a i n e d i s shown i n F i g u r e  Figure 4.  carried  The X - r a y d i a g r a m  f o r 10 thus  4.  Wood p u l p X - r a y  diagram  To o b t a i n q u a n t i t a t i v e d a t a o n t h e i n t e n s i t y o f t h e d i f f r a c t i o n pattern, a photovolt electronic densitometer ( M o d e l 525) was u s e d .  The z e r o r e a d i n g o f t h e d e n s i t o m e t e r was  c a l i b r a t e d b y t h e u n e x p o s e d a r e a o f t h e f i l m a n d i t s 100 p e r c e n t r e a d i n g , by p u t t i n g a p i e c e o f l e a d f o i l  on t h e f i l m .  The  50  f i l m was mounted on a microscope equipped w i t h a stage micrometer which c o n t r o l l e d p r e c i s e l y the movement of f i l m . The i n t e n s i t y r e a d i n g a t i n t e r v a l s of 0 . 2 mm.  along the  equator of the i n t e r f e r e n c e r i n g was p l o t t e d a g a i n s t the angle of  r e f l e c t i o n (2Q)  of  the powder camera was  on graph paper. 114.83 mm.,  S i n c e the inner diameter one degree of the 26  corresponded to one m i l l i m e t e r on the f i l m . curve thus o b t a i n e d was  The  intensity  the same as t h a t o b t a i n e d by method B  shown i n F i g u r e 6 , page $1. 2.  Method B A Geiger-counter X-ray spectrometer, type No.  was  used i n t h i s system.  i n F i g u r e 5«  The spectrometer geometry i s shown  A specimen was mounted on the g l a s s  h o l d e r and f i t t e d onto the sample p o s t . been c o l l i m a t e d by s l i t  1  (7 mm.  x 1.5  and c r e a t e d an angle of r e f l e c t i o n (2©) The d i f f r a c t e d r a y was passed through s l i t  12021,  specimen  The X-ray, which had  mm.),  h i t the specimen  as shown i n F i g u r e 5»  then f i l t e r e d by a n i c k e l f i l t e r  2 (4 mm.  x 0 . 5 mm.)  and  i n t o a goniometer.  The i n t e n s i t y of the d i f f r a c t e d beam r e g i s t e r e d by a goniometer 153)•  was r e c o r d e d a u t o m a t i c a l l y by a Brown Recorder (Model  A motor, a t t a c h e d t o the end of the goniometer, drove i t a t a constant speed o f \ rpm from r e f l e c t i o n angles of 90° The gear arm was  set t o run through a range of 32°  to 0 ° .  t o 10° o n l y .  The c h a r t of the r e c o r d e r was d r i v e n by a synchronous motor and c o u l d be c a l i b r a t e d d i r e c t l y i n degrees per minute. r e c o r d e d c h a r t , t h e r e f o r e , f u r n i s h e d a graph c o n t a i n i n g a  The  51 A - S O U R C E OF  X-RAYS  B-COLLIMATING SLIT NO. I C - SPECIMEN O-NICKEL  FILTER  E - COLLIMATING SLIT  NO.2  F - GONIOMETER G-MOTOR 26-ANGLE  FIGURE  5.  SPECTROMETER  10 FIGURE  GEOMETRY  20 2 6.  X-RAY  O  30  ( D E G R E E S )  DIFFRACTION  8 — THE  DRIVE OF R E F L E C T I O N  SPECTRUM  BREADTH OF T H E  0 0 2 P E A K IN  RADIANS  52  series  of peaks p r o p o r t i o n a l t o the i n t e n s i t y of the  d i f f r a c t e d X-ray beam p l o t t e d  a g a i n s t the angle of r e f l e c t i o n  (20). The X-ray machine was 20 v o l t , 60 c y c l e  operated from a  source of s u p p l y .  on the Brown Recorder was  normal  The m a g n i f i c a t i o n s c a l e  set a t 5 0 .  The d i f f r a c t i o n p a t t e r n  thus o b t a i n e d i s shown i n F i g u r e 5« E.  E v a l u a t i o n of  crystallinity  S i n c e the primary purpose  of t h i s study was  to  compare the r e l a t i v e v a r i a t i o n of c r y s t a l l i n i t y among c e r t a i n types of samples under t e s t , no attempt was the a b s o l u t e c r y s t a l l i n i t y .  made t o evaluate  C r y s t a l l i n i t y was  c r y s t a l l i n i t y index i n X-ray method A  e v a l u a t e d as a  (wood p u l p ) , and  c r y s t a l l i n i t y r a t i o i n X-ray method B ( h o l o c e l l u l o s e ) .  The  f ormulae rapplied are shown below. I.  C r y s t a l l i n i t y index C r y s t a l l i n i t y index ( C r . I . )  = (1  -  100 B I  )  100,  002 " min. I  where B i s the breadth of the 002 peak expressed i n r a d i a n s , I Q Q 2 i s the maximum i n t e n s i t y of the 002 peak i n a r b i t r a r y u n i t s , and I i m  and the (101 formula was  n  >  i s the minimum i n t e n s i t y between the 002 peak  + 101)  peak i n the same a r b i t r a r y u n i t s .  developed by Ant-Wuorinen (5)  This  and has been a p p l i e d  i n s t u d i e s of r e l a t i v e t r a n s i t i o n of c r y s t a l l i n i t y due t o v a r i o u s treatments  (72).  Because of the l i m i t e d accuracy i n  53  the measurement of i n t e n s i t y by the densitometer, was r e p o r t e d t o one decimal 2.  only.  Crystallinity ratio C r y s t a l l i n i t y r a t i o ( C r . R.) =  1  1  where I ( I Q I + 101) (101 + 101)  i  s  t i i e  peak, and I  M  m  a  x  I  N  #  i  m  u  m  (101 + 101)  (101 + 101)  + I  x  100,  min.  i n t e n s i t y o f the combined  i s the minimum i n t e n s i t y between  the 002 peak and the (101 + 101) The  the index  peak i n a r b i t r a r y u n i t s .  i n t e n s i t y should be c o r r e c t e d by s u b t r a c t i n g background  intensity, valid.  i f the c l a i m o f Anker-Rasch and McCarthy ( 3 ) i s  S i n c e the nature  experiment was d i f f e r e n t was necessary  o f the specimen h o l d e r used i n t h e i r from t h a t used i n t h i s experiment, i t  t o determine whether a background c o r r e c t i o n was  necessary. To do t h i s , two d i f f r a c t i o n i n t e n s i t y prepared,  c h a r t s were  one w i t h both specimen and sample h o l d e r , the other,  w i t h the specimen o n l y .  Comparison o f these two c h a r t s showed  t h a t the former gave a s l i g h t l y higher  intensity  on the  average due t o some r e f l e c t i o n caused by a specimen h o l d e r , but the d i f f e r e n c e was so s m a l l t h a t i t c o u l d be n e g l e c t e d . A c c o r d i n g l y , the i n t e n s i t y was c o r r e c t e d by s u b t r a c t i n g the i n i t i a l r e a d i n g from the I ( I Q ^ + IQT) and I the i n t e n s i t y c h a r t .  M  L  R  U  r e a d i n g on  The c r y s t a l l i n i t y r a t i o thus c a l c u l a t e d  was r e p o r t e d t o the n e a r e s t  hundredth.  I  RESULTS AND DISCUSSION A.  P a r t It  The degree o f c r y s t a l l i n i t y  o f pulp and  h o l o c e l l u l o s e of normal wood 1.  Results The r e s u l t s shown i n Table 4, page 55> and F i g u r e  page 56» i n d i c a t e t h a t c r y s t a l l i n i t y  7,  o f both wood pulp and  h o l o c e l l u l o s e i n c r e a s e s w i t h age from p i t h f o r about 15 y e a r s , then reaches a more or l e s s constant v a l u e . of  summerwood  The c r y s t a l l i n i t y  pulp and o f h o l o c e l l u l o s e , i s a l s o h i g h e r  t h a t o f the comparable springwood specimens.  than  These  d i f f e r e n c e s i n c r y s t a l l i n i t y are found t o be c l e a r l y s i g n i f i c a n t on a n a l y s i s o f v a r i a n c e , as shown i n Table page 57»  5j  F u r t h e r a n a l y s i s shows t h a t the d i f f e r e n c e i n  c r y s t a l l i n i t y between the 1 5 t h and the 2 1 s t non-significant.  growth r i n g s i s  T h i s i m p l i e s t h a t the c r y s t a l l i n i t y o f  j u v e n i l e wood t r a c h e i d s i n c r e a s e s w i t h age, whereas t h a t o f mature wood t r a c h e i d s i s more c o n s t a n t , e x h i b i t i n g variation.  negligible  M a t u r i t y i n t h i s case i s d e f i n e d as the age a t  which the curve o f c r y s t a l l i n i t y  v s age f l a t t e n s .  The n u m e r i c a l value o f c r y s t a l l i n i t y  index and  c r y s t a l l i n i t y r a t i o obtained i n t h i s study i s c o n s i d e r a b l y lower than those obtained by other workers. crystallinity  The range o f  index o f wood pulp i n the p r e s e n t r e s u l t i s  55 Table 4 .  Season  E f f e c t of age and season on c r y s t a l l i n i t y of wood pulp and h o l o c e l l u l o s e  Specimen  C r y s t a l l i n i t y index -X-ray method A(wood pulp)  3 Summerwood  1 2 3 av.  Springwood  1 2 3  av.  9  +  15  Crystallinity ratio -X-ray method B(holocellulose)  3  21  9  15  21  53.4 53-3 53-0 53.2  55.4 54.2 54.9 54.8  56.3 5 8 . 1 57.5 58.0 57.3 56.9 57.0 57.7  54.56 54.88 55.51 55.52 54.31 54.73 55.28 55.63  53.1 52.0 52.2 52.4  55.0 54.4 54.6 54.7  57.0 56.3 56.4 56.6  54.31 5 4 . 6 5 55.06 54.89 54.21 54.76 5 5 . 0 0 55.05  56.5 56.4 56.2 56.4  54.44 54.81 55.40 55.58  54.26 54.71  55.03 54.97  •Age from p i t h , y e a r s .  52.0 to 58.1, 63.O  whereas t h a t obtained by Ant-Wuorinen  (5) i s  (bleached s u l p h i t e wood p u l p ) , and t h a t by K o u r i s , Ruck  and Mason (72)  i s 70.6  (softwood d i s s o l v i n g wood p u l p ) .  The  range of c r y s t a l l i n i t y r a t i o of h o l o c e l l u l o s e obtained i n the p r e s e n t r e s u l t i s 54.21  t o 5 5 * 6 3 , whereas t h a t o b t a i n e d by  Anker-Rasch and McCarthy (3) c e l l u l o s e containing 96.7  i s about 6 4 . 5  percent a l p h a - c e l l u l o s e ) t o 6 5 . 0  (bleached k r a f t c e l l u l o s e c o n t a i n i n g 9 3 . 4 cellulose). cellulose  (bleached s u l p h i t e  percent a l p h a -  These are mainly due t o the d i f f e r e n t types of  examined. The i n c r e a s e i n c r y s t a l l i n i t y of wood t r a c h e i d s  d u r i n g the immature  stage (from the p i t h t o the 1 5 t h  growth  (A)  WOOD  PULP -  CRYSTALLINITY  INDEX  58 — • —  SUMMERWOOD  —O--SPRINGWOOD  57 X  w O  5 6  £  5 5  H W >"  5 3  z  z  o  52  51  (B) HOLOCELLULOSE -  >H Z  CRYSTALLINITY  RATIO  — • — SUMMERWOOD  56  < X  21  15  — O - - SPRINGWOOD  55 J  _J _J <  W  5 4  or o  53  FIGURE  7  .  VARIATION AND  OF  S E A S O N  CRYSTALLINITY IN  NORMAL  WITH W O O D  AGE  57  T a b l e 5« (A)  A n a l y s i s of v a r i a n c e o f c r y s t a l l i n i t y i n Table 4  C r y s t a l l i n i t y index  Source of v a r i a n c e  (wood pulp)  D. F.  S. S.  M. S»  F  Unit: replication age error  2 3 6  0.77 69.44 I.30  O.385 23.147 0.217  1.774106.668  N.S, ***  Sub u n i t : season AxS error  1 3 8  2.80 1.07 1.66  2.800 0.357 0.208  13.462 1.716  ** N.S,  23  77.04  Total  ** S i g n i f i c a n t a t 1. percent, l e v e l *** S i g n i f i c a n t a t 0 . 1 percent l e v e l N.S. N o n - s i g n i f i c a n t  (B)  Crystallinity ratio  Source of v a r i a t i o n  (holocellulose)  D.F.  S.S.  M. S.  Unit: replication age error  1 3 3  0.011 2.251 0.059  0.011 0.750 0.020  0.550 37.500  N.S. **  Subunit: season A x S error  1 3 4  O.388 0.152 0.030  O.388 0.051 0.008  48.500 6.375  ** N.S.  15  2.891  Total  * * S i g n i f i e a n t a t 1 percent N.S. N o n - s i g n i f i c a n t  level  F  58  ring)  seems to f o l l o w  a constant increment.  T h i s means that  the apparent degree of c r y s t a l l i n i t y might be age,  i f the  influence  of prepared f i b r e o r i e n t a t i o n i n  samples c o u l d be d i s c o u n t e d . f i b r e has  Such p r e f e r r e d  (46).  of  corresponding  interference  Neglect of t h i s e f f e c t d u r i n g the X-ray  experimental r e s u l t s The  o r i e n t a t i o n e f f e c t was  d u r i n g the X-ray exposure.  t h r e e - d i m e n s i o n a l one.  r o t a t i o n of specimen  only  two-  achieved r a t h e r  a p p a r e n t l y i n e v i t a b l e i n both X-ray methods.  T a n l g u c h i (142), i n which the  method, the  I t could be assumed t h a t  shown below.  Evidence s u p p o r t i n g t h i s p o i n t  to  difference  i n c r y s t a l l i n i t y might a c t u a l l y e x i s t among ages i n j u v e n i l e wood.  be  c o n s i d e r e d as s o l e l y a t t r i b u t a b l e  orientation effect.  present  by  o r i e n t a t i o n e f f e c t may  acid hydrolysis  was  Since' the  i n good agreement w i t h those obtained  be  than a  A slight orientation effect  completely r u l e d out by the  by  I n method B, no r o t a t i o n was .  dimensional randomness of f i b r e was  r e s u l t s can h a r d l y  the  minimized i n method A  d u r i n g the X-ray exposure, so t h a t  r e s u l t s are  in  (3,46,65,72)•  c a r e f u l p r e p a r a t i o n of sample, and  the  the  orientation  exposure w i l l cause a m i s l e a d i n g I n t e r p r e t a t i o n  applied  with  been found to g i v e r i s e t o - u n p r e d i c t a b l e changes  i n r e l a t i v e i n t e n s i t y of the pattern  correlated  the  of view i s  59 (a)  Tensile strength Wardrop  (152) has I l l u s t r a t e d that t e n s i l e  of t r a c h e i d s i n c r e a s e s w i t h t r e e age.  strength  Since an i n c r e a s e i n  t e n s i l e s t r e n g t h i s u s u a l l y accompanied by an i n c r e a s e i n crystallinity, crystallinity  i t i s t h e o r e t i c a l l y acceptable  that the  i n c r e a s e s w i t h age. But t h i s does not  n e c e s s a r i l y mean t h a t an i n c r e a s e i n t e n s i l e s t r e n g t h i s s o l e l y a t t r i b u t a b l e t o an i n c r e a s e i n c r y s t a l l i n i t y . angle and c e l l u l o s e molecular a l s o important (b)  i n this  Alpha-cellulose  Fibril  c h a i n l e n g t h d i s t r i b u t i o n are  respect. content  I t has been shown t h a t Cross and Bevan c e l l u l o s e content  ( 7 0 , 1 5 2 ) , or h o l o c e l l u l o s e content  (164),  w i t h age f o r a g i v e n p e r i o d i n c e r t a i n s p e c i e s .  increases Since  there  i s a strong p o s i t i v e c o r r e l a t i o n between a l p h a - c e l l u l o s e content  and h o l o c e l l u l o s e content  and Bevan c e l l u l o s e content a l p h a - c e l l u l o s e content  (164), as w e l l as the Cross  ( 7 0 ) , i t may be assumed that the  i n c r e a s e s w i t h age.  I f this i s true,  then the c r y s t a l l i n i t y can be expected t o i n c r e a s e w i t h age, s i n c e a c e l l u l o s e o f h i g h a l p h a - c e l l u l o s e content always gives a h i g h degree of c r y s t a l l i n i t y  cf.  page.38.  (22).  60  (c)  Moisture regain The h i g h e r the c r y s t a l l i n i t y , the lower  moisture r e g a i n w i l l be.? Wardrop (152)  Moisture r e g a i n data obtained by  showed i t to decrease w i t h age.  i n d i c a t e s the f o l l o w i n g two  the  This  possibilities:  i ) C r y s t a l l i n i t y might i n c r e a s e w i t h age so t h a t moisture r e g a i n would decrease w i t h  age.  i i ) The h e m i c e l l u l o s e f r a c t i o n c o u l d decrease w i t h age. t h i s i n s t a n c e , moisture r e g a i n would a l s o decrease  In with  age. o  I t has been noted by Ranby (11)  t h a t the  lower  l a t t i c e order of wood c e l l u l o s e , as compared w i t h t h a t of c o t t o n c e l l u l o s e , should be due to the presence monosaccharides i n the c e l l u l o s e c h a i n s . (22)  of other  Conrad and  a l s o claimed t h a t an i n c r e a s e i n a c c e s s i b i l i t y  occur when r e l a t i v e l y low-molecular-weight b e t a and gamma c e l l u l o s e are p r e s e n t .  Scroggie will  m a t e r i a l s such as  I f these workers are  c o r r e c t , then h o l o c e l l u l o s e near the p i t h , which c o n t a i n s h i g h e r h e m i c e l l u l o s e as r e v e a l e d by Zobel et a l (165), should give lower c r y s t a l l i n i t y . ' the present r e s u l t s .  T h i s i s i n good agreement w i t h  Thus both of the above mentioned  p o s s i b i l i t i e s are t h e o r e t i c a l l y a c c e p t a b l e . The present r e s u l t s d i s a g r e e w i t h those obtained by P r e s t o n , Hermans and Weidinger  7  c f . Table 3  ( 1 1 3 ) , who  found t h a t the  61  crystalline-non-crystalline  r a t i o decreased w i t h age.  samples used i n t h e i r study were Cross and Bevan  The  cellulose.  A c c o r d i n g t o the standard procedure f o r p r e p a r i n g the Cross and Bevan c e l l u l o s e , an end-point reached.  the sample should be d e l i g n i f i e d The time of d e l i g n i f i c a t i o n  until  required  to r e a c h t h i s end-point f o r v a r i o u s samples i s v a r i a b l e .  If  a sample taken near the p i t h i s assumed t o have a h i g h e r l i g n i n content than one near the bark, then the time of d e l i g n i f i c a t i o n f o r the former should be r e l a t i v e l y l o n g , and the d u r a t i o n of r e c r y s t a l l i z a t i o n of c e l l u l o s e  chains  d u r i n g the d e l i g n i f i c a t i o n would be c o n s i d e r a b l y prolonged. Consequently, the c e l l u l o s e  thus prepared might  give higher  c r y s t a l l i n i t y as compared w i t h the one near the bark, even .though the i n i t i a l c r y s t a l l i n i t y was  i d e n t i c a l f o r both  samples. In both the present experiment  and t h a t of  T a n i g u c h i (142), time of d e l i g n i f i c a t i o n was  kept c o n s t a n t .  The f i n a l l i g n i n content of each sample might t h e r e f o r e be v a r i a b l e s i n c e no end-point technique was  applied.  Thus the  lower v a l u e of c r y s t a l l i n i t y observed near the p i t h may  be  due t o a s l i g h t l y h i g h e r l i g n i n content i n the pulp sample. The v a r i a t i o n  of e x t r a c t i v e content may  also affect  the f i n a l  •J  result  since i t w i l l  i n f l u e n c e the r a t e of p e n e t r a t i o n of  c h e m i c a l s , which i n t u r n g i v e s d i f f e r e n t delignification.  degrees  of  I f i t i s assumed t h a t e x t r a c t i v e content i s  h i g h e r near the p i t h , then i t s d e l i g n i f i c a t i o n would be  62  poorer than that near the bark when the time o f Is kept constant f o r both samples.  delignification  I t i s apparent t h a t the  method of sample p r e p a r a t i o n w i l l c r i t i c a l l y a f f e c t the f i n a l r e s u l t s and w i l l l e a d t o d i f f e r e n t  interpretations.  The o b s e r v a t i o n t h a t summerwood has h i g h e r c r y s t a l l i n i t y than springwood i s i n good agreement w i t h H o l z e r and Lewis  ( 5 7 ) , and L i n d g r e n ( 7 7 ) .  The d i f f e r e n c e i n  c r y s t a l l i n i t y between summerwood and springwood i s s m a l l e r than was expected.  T h i s might be due t o the f a c t  that the  summerwood sample c o n t a i n e d about 50 percent o f springwood t r a c h e i d s because o f i n a c c u r a c y i n d i s s e c t i o n and t o the a n a t o m i c a l c h a r a c t e r i s t i c s o f a wood such as western hemlock. U s i n g the same argument o f the p r e v i o u s paragraph, one might expect summerwood t o be o f h i g h e r c r y s t a l l i n i t y , s i n c e i t c o n t a i n s a lower p r o p o r t i o n of l i g n i n than springwood. at  the end o f a g i v e n time o f d e l i g n i f i c a t i o n ,  might have been removed from the r e l a t i v e l y  less  Thus  lignin  lignin-rieh  springwood. 2.  Probable mechanism o f v a r i a b i l i t y o f c r y s t a l l i n i t y i n wood The mechanism o f v a r i a b i l i t y o f c r y s t a l l i n i t y w i t h  age and season i s unknown, because o f the inadequate i n f o r m a t i o n a v a i l a b l e about the mechanism o f the f o r m a t i o n of cellulose crystallites  and f i b r i l s  o f the c e l l w a l l .  (153) has proposed t h a t c r y s t a l l i z a t i o n  Wardrop  of c e l l u l o s e i s  f a c i l i t a t e d by the absence o f l i g n i n , based on the f a c t  that  63  c e l l u l o s e d i s p l a y s i t s h i g h e s t c r y s t a l l i n i t y v a l u e when the l i g n i n content i s low.  I f t h i s hypothesis i s c o r r e c t ,  summerwood c e l l u l o s e should be more h i g h l y c r y s t a l l i z e d  than  springwood c e l l u l o s e because the p r o p o r t i o n of c e l l u l o s e i n the summerwood has been found t o be h i g h e r than t h a t o f springwood, w h i l e the p r o p o r t i o n o f l i g n i n i n summerwood i s lower than t h a t o f springwood ( I l 6 , l 6 1 ) .  C r y s t a l l i n i t y might  a l s o i n c r e a s e w i t h age i n j u v e n i l e wood, s i n c e the c e l l u l o s e content has been shown t o i n c r e a s e w i t h age f o r g i v e n p e r i o d s i n c e r t a i n s p e c i e s (70,152,164).  The h y p o t h e s i s proposed by  Wardrop remains t o be proved. B.  P a r t I I : "• The degree o f c r y s t a l l i n i t y o f pulp and h o l o c e l l u l o s e from r e a c t i o n wood as compared to normal wood  1.  ,  ••  Results The c r y s t a l l i r i i t i e s o f pulp and h o l o c e l l u l o s e o f  r e a c t i o n wood as compared t o those o f normal wood are shown i n Table 6, page 64.  A n a l y s i s o f v a r i a n c e (Table 7, page 64)  shows t h a t c r y s t a l l i n i t y o f compression  wood f i b r e s and  h o l o c e l l u l o s e i s s i g n i f i c a n t l y lower than t h a t o f normal wood, w h i l e c r y s t a l l i n i t y o f t e n s i o n wood i s s i g n i f i c a n t l y h i g h e r than t h a t o f normal wood i n the form of both pulp and holocellulose.  These a r e d i s c u s s e d s e p a r a t e l y below.  64  Table 6 .  C r y s t a l l i n i t y index -X-ray method A(wood pulp)  Replication  1 2 3 av.  C-T*  C-N  D-N  D-C  C-T  C-N  D-N  D-C  6?.8 66.2 65.8 66.6  55.4 54.8 54.8 55.0  54.9 54.1 53.9 54.3  47.5 46.5 45.2 46.4  57.74 57.71  54.55 54.35  53.84 53.79  52.86 52.41  57.73  54.45  53.82  52.64  represents represents represents represents  Table 7.  cottonwood cottonwood Douglas f i Douglas f i  t e n s i o n wood normal wood r normal wood r compression wood  A n a l y s i s of v a r i a n c e o f c r y s t a l l i n i t y i n Table 6  Crystallinity  Source of v a r i a t i o n  ••Significant •••Significant  index  (wood pulp)  D. F. 2  Replication Type o f wood Error Total  (B)  Crystallinity ratio --X-ray method B(holocellulose)  1  •C-T C-N D-N D-C  (A)  C r y s t a l l i n i t i e s of r e a c t i o n wood  11  M. S.  •., 4 . 5 3 5 623.062 1.165 628.762  2.268 207.687 0.194  F 11.691 1070.552  ** ***  a t 1 percent l e v e l a t 0 . 1 percent l e v e l  Crystallinity ratio  Source o f v a r i a t i o n Replication Type o f wood Error Total  s. s.  (holocellulose)  D. F. 1 3 3 7  s. S.  M. S.  F  O.O67 28.506 0.056 28.629  O.O67 9.502 0.019  3.526 500.114  ••• S i g n i f i c a n t a t 0 . 1 percent N.S. N o n - s i g n i f i c a n t  level  N.S. ***  65  2.  Compression wood The  present  r e s u l t s might be expected i n view o f  the lower a l p h a - c e l l u l o s e content, h i g h e r l o n g i t u d i n a l shrinkage wood.  and lower s t r e n g t h values  observed i n compression  The c o r r e l a t i o n o f these three p r o p e r t i e s t o low degree  of c r y s t a l l i n i t y has been d i s c u s s e d p r e v i o u s l y . ^  The present  d i s c u s s i o n w i l l be c o n f i n e d t o the problem as t o why the c r y s t a l l i n i t y i n compression wood should be low. I n compression wood, the decreased t r a c h e i d l e n g t h is  u s u a l l y accompanied by an i n c r e a s e i n f i b r i l a n g l e .  These  a t t r i b u t e s are a s s o c i a t e d with an i n c r e a s e d number o f o b l i q u e a n t i c l i n a l d i v i s i o n s i n the cambium, occasioned i n c r e a s e d r a d i a l growth r a t e (156). t h a t vigorous  by the  I t has been p o i n t e d out  r a d i a l growth i s achieved  by p e r i c l i n a l  d i v i s i o n o f the f u s i f o r m i n i t i a l s o f the cambium ( 1 1 1 ) .  Thus,  i f r a p i d p e r i c l i n a l d i v i s i o n i s accompanied by an i n c r e a s e d number o f o b l i q u e a n t i c l i n a l d i v i s i o n s , then a wider growth r i n g w i l l produce s h o r t e r t r a c h e i d s (155)•  This implies that  f i b r i l angle as w e l l as f i b r e l e n g t h are simply a f u n c t i o n o f r a t e of change of growth i n c i r c u m f e r e n c e . Since the same r e l a t i o n s h i p s are found i n the j u v e n i l e wood, i t f o l l o w s t h a t the r e l a t i o n s h i p o f f i b r i l angle and f i b r e l e n g t h t o growth r a t e holds f o r both normal wood and compression wood.  8  cf.  Table 3 .  A c c o r d i n g l y , t h e r e would be no  66  appreciable differences i n f i b r i l  angle between two t r a c h e i d s  as long as they a r e formed i n a r i n g o f the same growth i r r e s p e c t i v e o f age or wood c o n d i t i o n .  rate,  T h i s i s confirmed by  Wardrop and Dadswell ( 1 5 5 ) J who claimed that compression wood t r a c h e i d s a r e a p p a r e n t l y no d i f f e r e n t from normal wood t r a c h e i d s of  t h e same l e n g t h so f a r as the f i b r i l  is  concerned.  angle o f the l a y e r S2  From t h i s p o i n t o f view, compression wood may  be c o n s i d e r e d more j u v e n i l e than a d j a c e n t wood o f the same age. The p r o p e r t i e s o f compression and j u v e n i l e wood compared t o normal, mature wood show t h a t both j u v e n i l e wood and compression wood have lower c e l l u l o s e c o n t e n t , t r a c h e i d l e n g t h , t e n s i l e s t r e n g t h , and h i g h e r f i b r i l shrinkage and l i g n i n c o n t e n t .  angle, l o n g i t u d i n a l  Consequently, t h e p r e v i o u s  assumption that compression wood can be regarded more j u v e n i l e t h a n adjacent normal wood seems a c c e p t a b l e . Under t h i s assumption, compression wood s h o u l d , t h e o r e t i c a l l y , give lower c r y s t a l l i n i t y as observed i n the present study. 3.  T e n s i o n wood The h i g h degree o f c r y s t a l l i n i t y o f c e l l u l o s e found  in  t e n s i o n wood as compared w i t h normal wood i s i n good  agreement w i t h the work o f Wardrop and Dadswell 157).^  The s t r u c t u r e o f t e n s i o n wood has been w e l l e s t a b l i s h e d  by means o f p o l a r i z i n g microscopy and X-ray  9NO  (11,153,154,  n u m e r i c a l data were g i v e n i n t h e i r  diffraction  results.  67  (154,157)•  I  n  b r i e f , there exists a t h i c k inner  gelatinous  l a y e r i n a d d i t i o n t o the l a y e r s S I , S 2 and S3, or the S3 l a y e r , or both S2 and S3  l a y e r s , may be l a c k i n g .  The f i b r i l  angle i n t h i s a d d i t i o n a l l a y e r has been shown t o be approximately 5° w i t h r e s p e c t fibre.  t o the l o n g i t u d i n a l a x i s of  F u r t h e r evidence has shown that t h i s l a y e r i s  u n l i g n i f i e d and that  i t s cellulose i s i n a highly crystalline  state. On r e v i e w i n g c h a r a c t e r i s t i c s o f t e n s i o n wood, the q u e s t i o n may be r a i s e d as t o whether the h i g h c r y s t a l l i n i t y o f c e l l u l o s e i n t e n s i o n wood i s a t t r i b u t a b l e t o a l l l a y e r s of the secondary w a l l or s o l e l y t o the a d d i t i o n a l g e l a t i n o u s Wardrop and Dadswell (157) point  have s t u d i e d  o f view o f e q u i l i b r i u m  layer.  t h i s problem from the  moisture c o n t e n t , d e n s i t y , and  sharpness o f an X-ray d i f f r a c t i o n p a t t e r n .  They f i n a l l y  concluded t h a t the h i g h degree o f c r y s t a l l i n i t y o f c e l l u l o s e i n tension  wood was s o l e l y a t t r i b u t a b l e t o a greater  l a t e r a l order i n the c r y s t a l l i n e r e g i o n  degree of  of the g e l a t i n o u s  l a y e r , whereas the p a r a c r y s t a l l i n e phase (or the amorphous phase) o f the r e s t o f the l a y e r s was s i m i l a r i n both normal and tension  wood. Since t e n s i o n wood c o n s i s t s  of c e l l u l o s e of high  c r y s t a l l i n i t y , i t should possess a l l the c h a r a c t e r i s t i c s of highly  c r y s t a l l i n e c e l l u l o s e g i v e n i n Table 2 .  several deviations  There a r e  from t h i s t h e o r e t i c a l e x p e c t a t i o n however:  abnormally h i g h l o n g i t u d i n a l shrinkage ( 1 7 , 2 0 , 2 4 , 1 5 4 ) , low  68  s t r e n g t h values  f o r f i b r e s t r e s s a t the p r o p o r t i o n a l l i m i t o f  bending, modulus o f r u p t u r e , modulus of e l a s t i c i t y , work t o the p r o p o r t i o n a l l i m i t , work t o u l t i m a t e shear ( 1 3 ) .  l o a d and l o n g i t u d i n a l  T e n s i o n wood does not decrease the toughness ( 1 9 ) ,  which i s supposed t o be lower i f c r y s t a l l i n i t y high.-  1,0  of c e l l u l o s e i s  S e v e r a l workers ( 1 7 , 1 9 , 1 5 4 ) have suggested p o s s i b l e  explanations,  but f u r t h e r i n v e s t i g a t i o n s a r e r e q u i r e d .  Even some chemical p r o p e r t i e s o f t e n s i o n wood are at  v a r i a n c e w i t h those expected.  F o r i n s t a n c e , the a l p h a -  c e l l u l o s e content of t e n s i o n wood i s s i g n i f i c a n t l y h i g h e r  than  t h a t of normal wood, whereas the pentosan content i s lower Thus some workers p o i n t e d  (17).  out t h a t the c e l l u l o s e i n t e n s i o n  wood was o f longer molecular c h a i n than the c e l l u l o s e i n normal wood ( 1 7 ) .  Nevertheless,  the degree o f p o l y m e r i z a t i o n  the h o l o c e l l u l o s e o f t e n s i o n wood was r e p o r t e d t h a t of normal wood  found i n  t o be lower than  (11).  I t i s c l e a r now t h a t a s i n g l e f a c t o r such as c r y s t a l l i n i t y , which i s found t o be s t r o n g l y c o r r e l a t e d w i t h p h y s i c a l and chemical p r o p e r t i e s o f c e l l u l o s e and wood under normal c o n d i t i o n s , cannot be a p p l i e d t o e x p l a i n the behavior of r e a c t i o n wood without c o n s i d e r i n g the e f f e c t s o f some factors.  other  Gross anatomical s t r u c t u r e a l s o has a r o l e as  important as f i n e s t r u c t u r e .  A s i m i l a r abnormality can a l s o be found i n compression wood, which has a lower c r y s t a l l i n i t y accompanied by a very low value o f toughness. i U  69  c  «  Part I I I :  The degree o f c r y s t a l l i n i t y  of h o l o c e l l u l o s e  of decayed wood 1.  Results Some of the X-ray  s p e c t r a of decayed wood  h o l o c e l l u l o s e a r e shown i n F i g u r e 8 , page 7 1 .  The v a r i a t i o n  i n the c r y s t a l l i n i t y r a t i o o f wood h o l o c e l l u l o s e due t o decay i s shown i n Table 8 , page 7 0 , and F i g u r e 9 , page 7 2 . A n a l y s i s o f v a r i a n c e (Table 9 , page 70) i n d i c a t e s t h a t both decay and type o f wood a r e c l e a r l y s i g n i f i c a n t a t 0 . 1 level.  percent  F u r t h e r a n a l y s i s shows the f o l l o w i n g :  (a) C r y s t a l l i n i t y  o f h o l o c e l l u l o s e i s g r e a t l y i n c r e a s e d due  to decay i n both normal and r e a c t i o n wood. (b) The r e l a t i v e magnitude of i n c r e a s e i n c r y s t a l l i n i t y i s approximately  i d e n t i c a l f o r each type of wood.  the order o f d e c r e a s i n g c r y s t a l l i n i t y  a f t e r decay  remains the same as t h a t o f the c o n t r o l s . crystallinity  Thus  The order of  of d i f f e r e n t types of decayed wood  depends mainly on the i n i t i a l  crystallinity  of wood  r a t h e r than on the h i s t o r y o f decay. (c) The r a t e of i n c r e a s e i n c r y s t a l l i n i t y the e a r l i e r  stage o f decay, r e p r e s e n t e d by a 6 percent  weight l o s s , but I t l e v e l s t o almost crystallinity  a slower r a t e .  statistically  constant  t h e r e a f t e r except i n compression  where c r y s t a l l i n i t y at  i s very r a p i d i n  is still  i n c r e a s i n g t o stage B, but  In this l a t t e r  significant.  wood,  case, the i n c r e a s e i s  70  Table 8 .  C r y s t a l l i n i t y r a t i o o f h o l o c e l l u l o s e o f decayed wood  Replication  Type o f wood  Control  Decay stage A  Decay stage B  Cottonwood t e n s i o n wood  1 2 av.  57.74 57-71 57.73  59.7O 59.50 . 59.60  59.56 59.70 59.63  Cottonwood normal wood  1 2 av.  54.35 54.55 54.45  55.95 55.83 55.89  55.90 56.17 56.04  Douglas f i r normal wood  1 2 av.  * 53.84 53.79 53.82  54.50 54.71 54.61  Douglas f i r compression wood  1 2 av.  Table 9 .  52.41 . 52.86 52.64  54.65 54.59 54.62 53.88 53.83  53.46 53.32  A n a l y s i s of v a r i a n c e o f c r y s t a l l i n i t y r a t i o i n Table 8  Source o f v a r i a t i o n  D. F.  S. S.  Unit: replication type o f wood error  1 3 3  0.061 111.009 O.O83  Subunit: treatment t x w error  2 6 8  8.911 I.I98 0.125  23  I2I.387  Total  '  '  ** S i g n i f i c a n t a t 1 percent l e v e l *** S i g n i f i c a n t a t 0.1,.percent l e v e l N.S. N o n - s i g n i f i c a n t  M. S.  0.061 ' 2.179 37.003 I3215.OOO 0.028 4.456 0.200 0.016  278.500 I2.50O  N.S. ***  *** **  71  —  i  10 2 FIGURE  8.  9  X-RAY FIR  i  •  >  20 ( D E G R E E S )  DIFFRACTION  SPECTRA  OF  •  30  DOUGLAS  HOLOCELLULOSE  A.  DECAYED  NORMAL  WOOD, STAGE  B  B. C  DECAYED COMPRESSION W O O D , S T A G E COMPRESSION W O O D , CONTROL  B  72  FIGURE  9.  EFFECT OF DECAY AND T Y P E O F WOOD ON CRYSTALLINITY RATIO OF HOLOCELLULOSE C-T C O T T O N W O O D T E N S I O N WOOD C-N C O T T O N W O O D NORMAL WOOD D-N D O U G L A S FIR NORMAL WOOD D-C D O U G L A S FIR C O M P R E S S I O N WOOD  73  In order t o understand  the probable mechanism  behind these experimental r e s u l t s , the b i o c h e m i c a l t r a n s f o r m a t i o n of c e l l u l o s e and wood which may decay should be 2.  occur d u r i n g  reviewed.  B i o c h e m i c a l t r a n s f o r m a t i o n of c e l l u l o s e Though much has been l e a r n e d r e g a r d i n g the  enzymatic  d e g r a d a t i o n of c o t t o n and m o d i f i e d  cellulose,  enzymatic  breakdown of whole wood i s l e s s w e l l  understood.  T h i s i s due t o the r e l a t i v e complexity of wood compared t o other c e l l u l o s i c m a t e r i a l s , and the inadequacy  of present  knowledge of the chemical s t r u c t u r e of wood, i n p a r t i c u l a r  of  the l i g n i n .  on  enzymatic  The f o l l o w i n g p r e s e n t a t i o n i s based p r i m a r i l y  d e g r a d a t i o n of c e l l u l o s e r a t h e r than wood. The energy  t h a t hyphae r e q u i r e f o r growth i s  d e r i v e d from that a v a i l a b l e available  i n glucose.  t o hyphae by the p h y s i o l o g i c a l  T h i s energy  o x i d a t i o n , i n which  one mole of glucose p r o v i d e s a t h e o r e t i c a l amount of equivalent to 676.6 k c a l . C  6 12°6 H  +  6 0  2  •  energy  (131).  6 H0 2  In order f o r t h i s r e a c t i o n transformed t o g l u c o s e .  i s made  + 6 C0  2  A F = -676.6 kcal.  t o proceed, c e l l u l o s e must be  The b i o c h e m i c a l t r a n s f o r m a t i o n of  c e l l u l o s e i n t o glucose i n c l u d e s two major s t e p s . Step 1:  T r a n s f o r m a t i o n of the n a t i v e c e l l u l o s e  into  i n d i v i d u a l l i n e a r c e l l u l o s e molecules by  splitting  of the t h r e e - d i m e n s i o n a l c r o s s - l i n k a g e . Step 2:  Breakdown of the l i n e a r c e l l u l o s e chains i n t o  glucose.  74  Both o f these r e a c t i o n s are c a r r i e d out by enzymes s e c r e t e d by hyphae.  Recent s t u d i e s (76,115) have shown t h a t  there a r e a t l e a s t two types o f enzymes which a r e r e s p o n s i b l e f o r the b i o c h e m i c a l t r a n s f o r m a t i o n o f c e l l u l o s e The  molecules.  f i r s t type of enzyme i s r e s p o n s i b l e f o r making c e l l u l o s e  molecules  a v a i l a b l e f o r r e a c t i o n , corresponding  t o step  1,  w h i l e t h e second type o f enzyme i s r e s p o n s i b l e f o r h y d r o l y s i s of the l i n e a r p o l y s a c c h a r i d e i n t o sugars, corresponding t o step 2 .  The former type i s known as c e l l u l a s e  the l a t t e r i s named Cx ( 1 1 5 ) .  The condensed  (130), whereas  stepwise  t r a n s f o r m a t i o n i s i l l u s t r a t e d i n Table 1 0 .  Table 10.  Stepwise b i o c h e m i c a l t r a n s f o r m a t i o n o f c e l l u l o s e i n t o glucose (131) Native c e l l u l o s e 1  crystalline region  (cotton) ,  amorphous r e g i o n (rapid)  (slow)  ... r u p t u r e o f H-bonds, van der Waals f o r c e s , by c e l l u l a s e Linear Polysaccharide ... P o l y s a c c h a r i d a s e enzyme, Cx, a c t i n g Cellobiose ... C e l l o b i a s e a c t i n g  A b s o r p t i o n i n t o organism  75  I n the case of wood, only r e s t r i c t e d groups of f u n g i are a b l e to u t i l i z e i t f o r food. a s s o c i a t i o n between c e l l u l o s e and r e s p o n s i b l e f o r such r e s t r i c t i o n .  The  nature of  the  l i g n i n of wood i s p r i m a r i l y I t has  been suggested t h a t  the b i o c h e m i c a l  transformation  of wood c e l l u l o s e i n t o l i n e a r  polysaccharides  Is c a r r i e d out by an unknown f a c t o r  "X"  presumably enzyma.tic, possessed only by f u n g i adapted to t h i s type of substance ( 2 3 ) .  The  symbol "X"  has been used t o  i d e n t i f y the as-yet-unknown enzymes r e s p o n s i b l e f o r t h i s transformation.  Absence of t h i s f a c t o r accounts f o r the  i n a b i l i t y of non-wood-destroying f u n g i to u t i l i z e wood f o r food. glucose 3.  The  transformation  from l i n e a r p o l y s a c c h a r i d e s  i s the same as t h a t of n a t i v e c o t t o n  Preference  of enzymic  to  (23).  attack  Evidence i n d i c a t e s t h a t the enzymic degradation  of  c e l l u l o s e s t a r t s p r e f e r a b l y from the amorphous r e g i o n r a t h e r than randomly.  On the b a s i s o f . a d i f f e r e n t i a l energy r e q u i r e -  ment, the amorphous r e g i o n i s p r e f e r a b l e to the  crystalline  r e g i o n because much l e s s energy w i l l be r e q u i r e d t o d i s l o d g e c e l l u l o s e c h a i n i n the former (131).  a  Assuming that, the a c t i o n  of the enzymes i s s i m i l a r to t h a t of d i l u t e m i n e r a l a c i d as d e s c r i b e d p r e v i o u s l y , i t i s reasonable t o presume that r e a c t i o n s t a r t s i n the amorphous r e g i o n and i n t o the c r y s t a l l i n e r e g i o n .  the  extends g r a d u a l l y  S e v e r a l workers (106,107,149)  have demonstrated the s i m i l a r i t y of a c i d and  enzymatic  h y d r o l y s i s by comparing the r a t e of h y d r o l y s i s .  Walseth  (150)  76  made use  of t h i s c h a r a c t e r i s t i c to determine the  of c e l l u l o s e , and  accessibility  h i s r e s u l t s were i n good agreement w i t h  those obtained by a c i d h y d r o l y s i s .  Norkrans and  Ranby  (106,107) a l s o claimed t h a t the enzymatic d e g r a d a t i o n apparently  occurred  i n e a s i l y a c c e s s i b l e regions  of  the  c e l l u l o s e aggregates, l e a v i n g more r e s i s t a n t p a r t i c l e s , and therefore  b e t t e r c r y s t a l l i z e d c e l l u l o s e , as a I t has  destroying  been shown (8)  residue.  t h a t there are c e r t a i n wood-  f u n g i whose hyphae advance by producing h e l i c a l l y  o r i e n t e d c a v i t i e s w i t h i n the t h i c k secondary w a l l of  fibres.  Such c a v i t i e s are of two  They  may  p r i n c i p a l geometric forms.  be b i c o n i c a l or c y l i n d r i c a l , w i t h c o n i c a l ends, and  o r i e n t e d p a r a l l e l t o the long a x i s of the f i b r i l . cases they may  be  These c a v i t i e s were found tcr be  r e s u l t of h y d r o l y s i s of c e l l u l o s e through enzymatic r e a c t i o n takes p l a c e  leaves  the c r y s t a l l i n e r e g i o n e n t i r e l y i n t a c t , so that  It  i s now  c l e a r that the i n i t i a l  s t a r t s from the amorphous r e g i o n . believed  fibril  the  activity.  i n the amorphous r e g i o n f i r s t ,  e x t e r n a l shape of the m i c r o f i b r i l and  and the  i s maintained.  enzymatic r e a c t i o n  This preference i s  to be the most probable f a c t o r r e s u l t i n g i n the  rapid increase  i n c r y s t a l l i n i t y during  decay observed i n t h i s study. may  In some  o r i e n t e d a t an angle of 20 t o 25 degrees to  the a x i s of the f i b r i l .  The  are  The  the e a r l i e r stage of  increase  in crystallinity  be a t t r i b u t e d to e i t h e r or both of the f o l l o w i n g f a c t o r s :  77  (a)  Removal of the amorphous m a t e r i a l s .  (b)  R e c r y s t a l l i z a t i o n during p r e p a r a t i o n of the specimen used f o r d e t e r m i n a t i o n  of  cellulose  crystallinity.  R e c r y s t a l l i z a t i o n i s q u i t e p o s s i b l e because the f r e e ends of the broken c h a i n on the s u r f a c e of the c r y s t a l l i t e always tend to arrange themselves f o r r e c r y s t a l l i z a t i o n . t h e r e i s no p o s s i b l e way  to show whether or not  l i z a t i o n a c t u a l l y took p l a c e , probably  Since  recrystal-  both r e c r y s t a l l i z a t i o n  and removal of amorphous m a t e r i a l s are r e s p o n s i b l e f o r an i n c r e a s e i n c r y s t a l l i n i t y a f t e r decay. As the decay p r o g r e s s e s ,  the enzymes w i l l  gradually  r e a c h the c r y s t a l l i n e r e g i o n which i s r e l a t i v e l y i n a c c e s s i b l e t o chemical  r e a c t i o n , and h i g h l y r e s i s t a n t t o enzymatic  hydrolysis. The r a t e of i n c r e a s e i n c r y s t a l l i n i t y w i l l slow down and  f i n a l l y l e v e l o f f , as shown i n stage B, F i g u r e  In other words, an i n c r e a s e d degree of c r y s t a l l i n i t y  9.  will  give r i s e t o g r e a t e r r e s i s t a n c e to enzymatic h y d r o l y s i s . T h i s i s i n good agreement w i t h r e s u l t s of other workers  (68,106,149,150). 4.  R e l a t i o n s h i p between l a t e r a l order and r a t e of enzymatic The  attack  present  r e s u l t shows that c r y s t a l l i n i t y  decayed-wood h o l o c e l l u l o s e depends l a r g e l y on of sound wood. two  points:  of  crystallinity  T h i s might be a t t r i b u t e d to the f o l l o w i n g  78  (a)  During the e a r l y stage o f deeay, the enzymes a t t a c k the amorphous r e g i o n s a t almost  the same r a t e f o r  v a r i o u s types o f wood. (b)  The degree o f p e r f e c t i o n of the l a t t i c e  structure i n  the c r y s t a l l i n e r e g i o n s i s heterogeneous r a t h e r than homogeneous.  There must be a s t a t i s t i c a l  of degree o f l a t e r a l  distribution  order.  Two mechanisms have thus f a r been p o s t u l a t e d i n order to e x p l a i n the breakdown o f c e l l u l o s e chains by enzymes. One i s a random cleavage mechanism and the other, an endwise a t t a c k mechanism (107)• much more probable  Since t h e former i s thought t o be  (131),  i t i s assumed t h a t the enzymes  randomly a t t a c k c e l l u l o s e chains a t the s u r f a c e of t h e crystallite. decrease  Thus both width and l e n g t h o f c r y s t a l l i t e  will  simultaneously as the decay advances. As shown i n p a r t I I , the order of d e c r e a s i n g  crystallinity  of h o l o c e l l u l o s e from v a r i o u s types o f wood i s  t e n s i o n wood, normal wood and compression wood. differences i n c r y s t a l l i n i t y schematic  These  can be r e p r e s e n t e d by the  l a t e r a l - o r d e r d i s t r i b u t i o n curve i l l u s t r a t e d by  Howsmon and S i s s o n ( 1 1 0 ) .  1 1  P o s t u l a t e d curves obtained i n  t h i s way a r e shown i n F i g u r e 10A, page 8 l . crystallinity  The h i g h  o f t e n s i o n wood i s c h a r a c t e r i z e d by a  n e g a t i v e l y skewed d i s t r i b u t i o n curve, whereas the low  c f . page 13  79 c r y s t a l l i n i t y of compression  wood i s c h a r a c t e r i z e d by a  p o s i t i v e l y skewed d i s t r i b u t i o n c u r v e . the sequence of enzymatic  In order to c o r r e l a t e  a t t a c k to the v a r i a t i o n of  c r y s t a l l i n i t y , the l a t e r a l order d i s t r i b u t i o n curves transformed F i g u r e 10B.  to two-dimensional The  diagrams as shown i n  l a t e r a l order i s assumed to be h i g h e s t at  the c e n t r a l p o r t i o n of the c r y s t a l l i n e r e g i o n , and g r a d u a l l y decrease  toward the s u r f a c e of the  to  crystallite.  Thus the h i g h l y c r y s t a l l i n e t e n s i o n wood possesses area of h i g h l a t e r a l order at the center of the w h i l e the weakly c r y s t a l l i n e compression area of low  are  a larger  crystallite,  wood has a l a r g e r  l a t e r a l order at the s u r f a c e of the  crystallite.  No d e f i n i t e b o r d e r l i n e a c t u a l l y e x i s t s between each phase of l a t e r a l o r d e r , so t h a t the t r a n s i t i o n of l a t e r a l order be regarded as As  should  continuous.  enzymatic  h y d r o l y s i s b e g i n s , the outermost a r e a  of low l a t e r a l o r d e r , which corresponds  to the amorphous  r e g i o n , w i l l be d i s s o l v e d away q u i c k l y to leave the r e l a t i v e l y h i g h l a t e r a l order p o r t i o n (see F i g u r e Consequently  IOC).  the degree of c r y s t a l l i n i t y of c e l l u l o s e  i n c r e a s e s r a p i d l y a t t h i s stage, as shown i n F i g u r e 9.  Since  the r e l a t i v e area of the h i g h l a t e r a l - o r d e r p o r t i o n i s not changed through F i g u r e 10D, expected  s u c c e s s i v e stages of decay, as shown i n  the order of degree of c r y s t a l l i n i t y can  t o remain the same as i n the  control.  be  8o  When a l l r e a d i l y a c c e s s i b l e c e l l u l o s e i s d i s s o l v e d and decay advances from stage A t o B, enzymatic a t t a c k  still  proceeds, but presumably a t slow r a t e , and only a t the s u r f a c e of the c r y s t a l l i t e  (150).  Hence the r a t e o f i n c r e a s e i n  c r y s t a l l i n i t y w i l l be n e g l i g i b l e a t t h i s stage, as demonstrated by the experimental  r e s u l t s summarized i n (c)  page 6 9 . As mentioned p r e v i o u s l y , c r y s t a l l i n i t y o f compression wood h o l o c e l l u l o s e i n c r e a s e d throughout stage B. low  lateral  T h i s can be e x p l a i n e d by i t s abnormally  order as i l l u s t r a t e d  there i s s t i l l  continuously  i n F i g u r e 10B.  At stage A,  a c o n s i d e r a b l e amount o f r e l a t i v e l y  l a t e r a l - o r d e r m a t e r i a l l e f t on the c r y s t a l l i t e  low  s u r f a c e of  compression wood (see F i g u r e IOC). The enzymatic a t t a c k continues  t o proceed a t a f a s t r a t e , a l l o w i n g the  crystallinity Figure  9.  t o i n c r e a s e as shown i n F i g u r e 10D, and  81  D  F I G U R E 10. S C H E M A T I C L A T E R A L ORDER DISTRIBUTION CURVE AND S E Q U E N C E O F ENZYMATIC A T T A C K ON T H E C R Y S T A L L I N E REGION A . S C H E M A T I C L A T E R A L ORDER DISTRIBUTION CURVE dQ _ QUANTITY OF CELLULOSE BELONGING TO A dO B.  CROSS  PARTICULAR SECTION  ORDER OF T H E  CRYSTALLINE  REGION  OF  CONTROL C.  DECAY  STAGE  A  (APPROX.  PERCENT  WT.  LOSS)  D.  DECAY  STAGE  B  ( A P P R O X . 15 P E R C E N T  WT.  LOSS)  LATERAL  ORDER  » M  6  >  >•  > ffigjgjjg  THE  CONCLUSIONS 1.  C r y s t a l l i n i t y o f wood p u l p and h o l o c e l l u l o s e o f t h e normal w e s t e r n hemlock wood sampled significantly  through successive  increases  growth r i n g s from t h e  p i t h t o about 15 y e a r s , a f t e r w h i c h i t r e a c h e s a more or l e s s constant 2.  value.  C r y s t a l l i n i t y o f wood p u l p and h o l o c e l l u l o s e o f summerwood from t h e w e s t e r n hemlock higher  3.  sampled i s s i g n i f i c a n t l y  t h a n t h a t o f springwood.  C r y s t a l l i n i t y o f wood p u l p and h o l o c e l l u l o s e o f t h e Douglas f i r c o m p r e s s i o n wood specimens i s c o n s i d e r a b l y l o w e r t h a n t h a t o f normal wood, whereas c r y s t a l l i n i t y o f wood p u l p and h o l o c e l l u l o s e o f t h e t e n s i o n wood samples o f cottonwood i s s i g n i f i c a n t l y h i g h e r wood.  4.  t h a n t h a t o f normal  '  The abnormal 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 r e a c t i o n wood - s u g g e s t t h a t c r y s t a l l i n i t y i s n o t t h e o n l y f a c t o r w h i c h a f f e c t s r e a c t i o n wood p r o p e r t i e s . other f a c t o r s responsible  There must be  f o r the properties of r e a c t i o n  wood. 5.  C r y s t a l l i n i t y o f cottonwood and Douglas f i r wood holocellulose increases  significantly  d u r i n g decay caused  by t h e brown^rot f u n g i , P o r i a i n c r a s s a t a and P o r i a monticola.  83  6.  The r a t e of increase i n c r y s t a l l i n i t y due t o decay i s very r a p i d during the i n c i p i e n t stage of decay represented by 6 percent weight l o s s , but becomes very slow and shows almost a constant value of c r y s t a l l i n i t y thereafter.  I n the case of compression wood, the  c r y s t a l l i n i t y increases through the stage of decay represented by 15 percent weight l o s s , but at a r a t e s l i g h t l y , lower than that of the e a r l i e r stage of decay. 7.  The order of degree of c r y s t a l l i n i t y f o r various woods a f t e r decay i s the same as the c o n t r o l s , i . e . , t e n s i o n wood e x h i b i t s the highest and compression wood the lowest value of c r y s t a l l i n i t y .  The ^relative value of  c r y s t a l l i n i t y a f t e r decay depends mainly upon the i n i t i a l c r y s t a l l i n i t y r a t h e r than the h i s t o r y of decay.  BIBLIOGRAPHY 1.  A l m i n , K.E. 1952. The r e a c t i o n between c e l l u l o s e and heavy water. Svensk P a p p e r s t i d n i n g . 55:767-770.  2.  Andress, K.R. 1928. Uber d i e Einwirkung von ma*ssig K o n z e n t r i e r t e r S a l p e t e r s a u r e auf C e l l u l o s e . Z. P h y s i k . Chem. A 1^6:279-288.  3.  Anker-Rasch, 0 . and McCarthy, J . L . 1954. Behaviour of c e l l u l o s e s i n sodium h y d r o x i d e s o l u t i o n s . Norsk Skogindustri. 10:329-333-  4.  Anker-Rasch, 0 . 1955* Some remarks r e g a r d i n g ' E v a l u a t i o n of the c r y s t a l l i n i t y of c e l l u l o s e from the X-ray d i f f r a c t i o n p i c t u r e s ' by 0 . Ant-Wuorinen. P a p e r i J a  Puu.  31:550.  5.  Ant-Wuorinen, 0 . 1955. E v a l u a t i o n of the c r y s t a l l i n i t y of c e l l u l o s e from X-ray d i f f r a c t i o n p i c t u r e s . F i n l a n d , The S t a t e I n s t i t u t e f o r T e c h n i c a l Research. Report No. 146. 82 pp.  6.  1955. Comments on the remarks by 0. AnkerRasch. P a p e r i Ja Puu. 3Z*551•  7.  A s s a f , A.G., Haas, R.H. and Purves, C.B. 1944. A study of the amorphous p o r t i o n of dry swollen c e l l u l o s e by an Improved t h a l l o u s e t h y l a t e method. J . Am. Chem.  8  Soc.  66:59-65.  8.  B a i l e y , I.W. 1954. C o n t r i b u t i o n s t o p l a n t anatomy. C h r o n i c a B o t a n i c a Co., Waltham. 258 pp.  9.  B a r r y , A . J . , P e t e r s o n , F.C. and K i n g , A . J . 1936. X-ray s t u d i e s of r e a c t i o n s of c e l l u l o s e i n non-aqueous systems. 1. I n t e r a c t i o n of c e l l u l o s e and l i q u i d ammonia. J . Am. Chem. Soc. £ 8 : 3 3 3 - 3 3 7 .  10.  Boer, J.H. 1935. The i n f l u e n c e o f van der Waal's f o r c e s and primary bonds on b i n d i n g energy, s t r e n g t h and o r i e n t a t i o n , w i t h s p e c i a l r e f e r e n c e t o some a r t i f i c i a l r e s i n s . Trans. F a r a . Soc. 3 2 : 1 0 - 3 8 .  11.  Bolam, F. ( e d . ) . 1958. Fundamentals of papermaking f i b r e s . B r i t i s h paper and Board Makers' A s s o c i a t i o n , England. 487 pp.  12.  Bonhoeffer, K.F. Wasserstoff.  1934. Reaktionen mit Schwerem Z. Elektrochem. 40:469-474.  85  13.  Brown, H.P., Panshin, A r . J . and F o r s a i t h , C.C. 1949. Textbook o f wood technology, V o l . I I . McGraw-Hill Book Co., Inc., New York. 783 pp.  14.  C a r o t h e r s , W.H. and Van N a t t a , F . J . 1933. Studies of p o l y m e r i z a t i o n and r i n g f o r m a t i o n . X V I I I . P o l y e s t e r s from w-hydroxy decanoic a c i d . J . Am. Chem. Soc. 5 5 : 4 7 1 4 - 4 7 2 8 .  15.  Champetier, G. and V i a l l a r d , R. I 9 3 8 . Exchange. r e a c t i o n o f c e l l u l o s e and heavy water. B u l l . Soc. Chem. 5:1042-1048.  16.  C h i t a l e , A.G. 1955* The e f f e c t o f temperature on the a b s o r p t i o n o f i o d i n e by c e l l u l o s e . Text. Res. J .  25:886-887.  17.  Chow, K.Y. 1946. A comparative study of the s t r u c t u r e and chemical composition o f t e n s i o n wood and normal wood i n beech. Forestry 20:62-77.  18.  C l a r k , G.L. and P a r k e r , E.A. 1937. An X-ray d i f f r a c t i o n study of the a c t i o n of l i q u i d ammonia on c e l l u l o s e and i t s d e r i v a t i v e s . J . Phys. Chem.  41:777-786.  19.  C l a r k , G.L. and T e r f o r d , H.C. 1955. Q u a n t i t a t i v e X-ray d e t e r m i n a t i o n of amorphous phase i n wood pulps as r e l a t e d t o p h y s i c a l and chemical p r o p e r t i e s . A n a l . Chem. £2:888-895.  20.  C l a r k e , S.H. 1937. The d i s t r i b u t i o n , s t r u c t u r e , and p r o p e r t i e s of t e n s i o n wood i n beech. Forestry  11:85-91.  21.  C l i b b e n s , D.A. and Ridge, B.P. 1928. The t e n s i l e s t r e n g t h and f l u i d i t y of c h e m i c a l l y m o d i f i e d c o t t o n . J . Text. I n s t . 12:T389-404.  22.  Conrad, C.C. and S c r o g g i e , A.G. 1945. Chemical c h a r a c t e r i z a t i o n o f rayon yarns and c e l l u l o s i c raw m a t e r i a l s . Ind. Eng. Chem. 32*592-598.  23.  Cowling, E.B. 1958. A review o f l i t e r a t u r e on the enzymatic d e g r a d a t i o n o f c e l l u l o s e and wood. U.S. F o r . Serv., F o r . Prod. Lab. Rept. No. 2116. 26 pp.  24.  Dadswell, H.E. 1958. Wood s t r u c t u r e v a r i a t i o n s o c c u r r i n g d u r i n g t r e e growth and t h e i r i n f l u e n c e on p r o p e r t i e s . J . I n s t , of Wood S c i . 1:1-24.  86  25.  2  °.  Davidson, G.F. 1940. P r o p e r t i e s of the o x y c e l l u l o s e s formed i n the e a r l y stages of o x i d a t i o n of c o t t o n c e l l u l o s e by p e r i o d i c a c i d and metaperiodate. J . T e x t . I n s t . 3JL:T8l-96. . .... 1943. The r a t e of change i n the p r o p e r t i e s of c o t t o n c e l l u l o s e under the prolonged a c t i o n of a c i d s . J . T e x t . I n s t . 34:T 87-96. :  27.  Denham, W.S. and Woodhouse, H. 1914. The m e t h y l a t i o n of c e l l u l o s e P a r t I I . H y d r o l y s i s of methylated c e l l u l o s e . J . Chem. Soc. T r a n s . 105:2^57-2^68.  28.  Doree, C. 1950• The methods of c e l l u l o s e c h e m i s t r y . 2nd ed. Chapman and H a l l L t d . , London. 543 pp.  29.  Douglas, S.D. and Stoops, W.N. 1936. Polymer d i s t r i b u t i o n i n v i n y l e s t e r r e s i n s . Ind. Eng. Chem.  28:1152-1155. 30.  Fahraeus, G. 1946. Enzyme p r e p a r a t i o n s from c e l l u l o s e decomposing b a c t e r i a . E x p e r i m e n t i a . 2:412-415.  31.  F l a s c h n e r , L. 1948. Rontgenographic d e t e r m i n a t i o n of the r e l a t i o n s h i p between c r y s t a l l i n e and amorphous substances i n c e l l u l o s e f i b r e s . Ann. P h y s i k . 2 ( 6 ) : 3 7 0 - 3 9 2 , Chem. A b s t . 42:8595.  32.  F l e t c h e r , H. and Houston, M.H. 1940. E f f e c t of l i g h t and heat on c o l o r and d e t e r i o r a t i o n of v i s c o s e , a c e t a t e and cuprammonium f a b r i c s . T e x t . Res. J .  11:4-11.  33.  F o r z i a t i , F.H., Stone, W.K., Rowen, J.W. and A p p e l , W.D. C o t t o n powder f o r i n f r a - r e d t r a n s m i s s i o n measurements. J . Res. Nat. Bur. Stand. 4 5 : 1 0 9 - 1 1 3 .  34.  F o r z i a t i , F.H. and Rowen, J.W. 1951. E f f e c t of changes i n c r y s t a l l i n e s t r u c t u r e on the i n f r a - r e d a b s o r p t i o n spectrum of c e l l u l o s e . J . Res. Nat. Bur. Stand. 46:38-42.  35.  F r e y - W y s s l i n g , A. 1936. Der Aufbau der p f l a n z l i c h e n Zellwande. Protoplasma £5:261-300.  36.  F r i l e t t e , V . J . , Hanle, J . and Mark, H. 1948. Rate of exchange of c e l l u l o s e w i t h heavy water. J . Am. Chem.  Soc.  37.  20:1107-1113.  G l a d d i n g , E.K. and Purves, C.B. 1943. E s t i m a t i o n of c a r b o n y l groups i n chromic anhydride o x y s t a r c h and o x y c e l l u l o s e by means of hydroxylamine. Paper Trade J . 1 1 6 ( 1 4 ) : 2 6 - 3 1 , Chem. A b s t . 320594.  8  7  38.  Glegg, R.E. 1951. The o x i d a t i o n of c e l l u l o s e by chromium t r i o x i d e . T e x t . Res. J . 21:143-140.  39.  G l u c k l i c h , E . 1943. The e f f e c t of heat on f i b r e s and yarns. T e x t i l e - R i n g . 1 : 2 9 - 3 3 , Chem. Abst. 40:5925.  40.  G o l d f i n g e r , G., Mark, H. and S i g g l a , S. 1943. Kinetics of o x i d a t i o n of c e l l u l o s e w i t h p e r i o d i c a c i d . Ind. Eng. Chem. 35:1083-1086.  41.  Greathouse, G.A. 1950. M i c r o b i o l o g i c a l d e g r a d a t i o n of cellulose. T e x t . Res. J . 2 0 : 2 2 7 - 2 3 8 .  42.  Gross, S.T. and C l a r k , G.L. 1938. A t e s t of the a l t e r n a t i v e s t r u c t u r e s proposed f o r c e l l u l o s e . Z. K r i s t . 422:357-366.  43.  Hermans, P.H. 1946. C o n t r i b u t i o n s t o the p h y s i c s of c e l l u l o s e f i b r e s . E l s e v i e r Pub. Co., I n c . , New York. 224 pp.  44.  . 1949. P h y s i c s and chemistry of c e l l u l o s e f i b r e s . E l s e v i e r Pub. Co., I n c . , New York. 534 pp.  45.  and Weidingger, A. 1946. t i o n of amorphous c e l l u l o s e .  68:2547-2552. 46.  On the r e c r y s t a l l i z a J . Am. Chem. Soc.  and . 1948. Q u a n t i t i a t l v e X-ray i n v e s t i g a t i o n on the c r y s t a l l i n i t y o f c e l l u l o s e f i b r e s , a background a n a l y s i s . J . A p p l . Phys.  12:491-506.  47.  _______ and . 1949. X-ray s t u d i e s on the c r y s t a l l i n i t y of c e l l u l o s e . J . Poly. S c i . 4:135-144.  48.  and . 1949. Degree o f l a t e r a l order In v a r i o u s rayons as deduced from X-ray measurements. J . P o l y . S c i . 4:145-151.  49.  and . 1949. Change i n c r y s t a l l i n i t y upon heterogenous a c i d h y d r o l y s i s of c e l l u l o s e f i b r e s . J . Poly. S c i . 4:317-322.  50.  and . 1949. Estimation of c r y s t a l l i n i t y of some polymers from X-ray i n t e n s i t y measurements. J . Poly. S c i . 4:709-723.  51.  and . 1950. Quantitative investigation of X-ray d i f f r a c t i o n by "amorphous" polymers and some other n o n - c r y s t a l l i n e substances. J . P o l y . S c i .  5:269-281.  88  52.  and . 1950. precipitated cellulose.  C r y s t a l l i n i t y of J . Poly. S c i . 5 565-568. :  53*  and . 195°• Note on d e n s i t y d e t e r m i n a t i o n of c e l l u l o s e f i b r e s by the f l o t a t i o n method i n carbon t e t r a c h l o r i d e . J . P o l y . S c i . 5 : 7 3 4 - 7 3 5 .  54.  and . 1951. C r y s t a l l i n i t y of c e l l u l o s e a f t e r treatment w i t h sodium hydroxide ( m e r c e r i z a t i o n ) . J . Poly. S c i . 6:533-538.  55. 56.  Herzog, R.O. K o l l . Z.  1926. Uber d i e Quellung der Z e l l u l o s e . 32:98-107.  . 1926. The nature o f the s t r u c t u r e o f c e l l u l o s e and i t s s i g n i f i c a n c e i n chemical t r a n s f o r m a t i o n s . J . Phys. Chem. 30:457-469.  57.  H o l z e r , W.F. and Lewis, H.F. 1950.. The c h a r a c t e r i s t i c s of unbleached k r a f t pulps from western hemlock, Douglas f i r , western r e d cedar, l o b l o l l y pine and b l a c k spruce. V I I . Comparison o f springwood and summerwood f i b r e s o f Douglas f i r . Tappi. 33:110-112.  58.  Hess, K., K i e s s i g , H. and Gundermann, J . 1941. Rontgenographische und elektronenmikroskopische Untersuchung der Vorgange beim Vermahlen von C e l l u l o s e . Z. Phys. Chem. B49:64-82.  59.  H e s s l e r , L.E. and Power, R.E. 1954. The use o f i o d i n e a b s o r p t i o n as a measure o f c e l l u l o s e f i b r e crystallinity. Text. Res. J . 2 4 : 8 2 2 - 8 2 7 .  60.  H i g g i n s , H.G. 1957* The use o f potassium c h l o r i d e d i s k s i n the i n f r a - r e d examination of f i b r o u s c e l l u l o s e and other s o l i d m a t e r i a l s . A u s t . J . Chem. 10:496-501.  61.  Holden, M. and Tracey, M.V. 1950. A study of enzymes t h a t can break down t o b a c c o - l e a f components. 2 . Digestive j u i c e of h e l i x o n defined substrates. Biochem. J . 42:407-414.  62.  Houston, M.H. and F l e t c h e r , H. 1940. The e f f e c t of l i g h t and heat on the breaking s t r e n g t h , c o l o r and copper number o f v i s c o s e , c e l l u l o s e a c e t a t e and cuprammonium rayon f i b r i c s . T r a n s . Kansas Acad. S c i . 4 3 : 3 0 9 - 3 1 1 , Chem. Abst. 35:2330.  63.  Howsmon, J.A. 1949. Water s o r p t i o n and the polyphase s t r u c t u r e o f c e l l u l o s e f i b r e s . T e x t . Res. J .  i#  12:152-162.  89  64.  Immergut, E.A. and Ranby, B.G. 1956. Heterogeneous a c i d h y d r o l y s i s of n a t i v e c e l l u l o s e f i b r e s . Ind. Eng. Chem. 4 8 : 1 1 8 3 - 1 1 8 9 .  65.  I n g e r s o l l , H.G. 1946. F i n e s t r u c t u r e of v i s c o s e rayon. J . A p p l . Phys. 1Z:924-939.  66.  I r v i n e , J.C. and H i r s t , E.L. 1922. The c o n s t i t u t i o n of p o l y s a c c h a r i d e s . P a r t V. The y i e l d of glucose from c o t t o n c e l l u l o s e . J . Chem. Soc. 121:1585-1591.  67.  _______ and __. 1923. The c o n s t i t u t i o n of polysaccharides. P a r t V I . The molecular s t r u c t u r e of c o t t o n c e l l u l o s e . J . Chem. Soc. 12^:518-5^2.  68.  K a r r e r , P., Schubert, P. and W e h r l i , W. 1925. Polysaccharide. XXXIII. Uber enzymetischeri Abbau von Kunstseide und n a t i v e r C e l l u l o s e . H e l v . Chim. Acta. 8:797-810.  69.  K a s t , W. and F l a s c h n e r , L. 1948. Eine rontgengraphische Methode zur Bestimmung des V e r h a l t n i s s e s von K r i s t a l l i n e r und amorpher Substanz i n Z e l l u l o s e f a s e r n , K o l l . Z. 111:6-15.  70.  Kennedy, R.W. and Jaworsky, J.M. i960. Variation i n c e l l u l o s e content of Douglas f i r . Tappi. 43(1)t 25-27.  71.  Kohara, J . and Okamota, H. 1955 • Permanence of wood. C r y s t a l l i n e r e g i o n of c e l l u l o s e i n o l d timber. J . Jap. F o r . Soc. 3Z*392-395? Chem. A b s t . 5 0 : 4 4 9 8 .  72.  K o u r i s , Iff., Ruck, H. and Mason, S.G. 1958. The e f f e c t of water removal on the c r y s t a l l i n i t y of c e l l u l o s e Can. J . Chem. 3 6 : 9 3 1 - 9 4 8 .  73.  , and . 1959. Note on the d e t e r m i n a t i o n of c r y s t a l l i n i t y index of c e l l u l o s e . Can. J . Chem. 3 Z * 9 9 8 .  74.  Kratky, 0 . 1935« Uber den m i z e l l a r e n Aufbau und d i e DeformationsvorgSnge b e i F a s e r s t o f f e n . K o l l . Z. 20:14-19.  75»  Kubo, T. and Kanamaru, K. 1938. Untersuchungen tiber d i e Umwandlung von H y d r a t c e l l u l o s e i n n a t h r l i c h e C e l l u l o s e . Z. Phys. Chem. 4 1 8 2 : 3 4 1 - 3 6 0 .  76.  Levinson, H.S. and Reese, E.T. 1950. Enzymatic h y d r o l y s i s of s o l u b l e c e l l u l o s e d e r i v a t i v e s as measured by change i n v i s c o s i t y . J . Gen. P h y s i o l . 33:601-628.  90  77•  L i n d g r e n , P.H. 1958. X-ray o r i e n t a t i o n i n v e s t i g a t i o n on some Swedish c e l l u l o s e m a t e r i a l s . A r k i v . f o r Kemi. 1 2 ( 3 8 ) : 4 3 7 - 4 5 2 .  78.  Loeb, L. and S e g a l , L. 1955. S t u d i e s of the e t h y l e n e d i a m i n e - c e l l u l o s e complex. I . Decomposition of complex by s o l v e n t s . J . P o l y . S c i . 15:343-354.  79.  and __. 1955. The treatment of c o t t o n c e l l u l o s e w i t h aqueous s o l u t i o n s of ethylamine. Text. Res. J . 2 5 : 5 1 6 - 5 1 9 .  80.  L o v e l l , E.L. and Goldschmid, 0. 1946. Ind. Eng. Chem. 3 8 : 8 1 1 - 8 1 7 .  81.  Magne, F.C., P o r t a s , H.J. and Wakeham, H. 1947. A c a l o r i m e t r i c i n v e s t i g a t i o n of moisture i n t e x t i l e f i b r e s . J . Am. Chem. Soc. 6J:1896-1902.  82.  Majury, T.G. 1956. Iodine s o r p t i o n as an index of f i b r e c r y s t a l l i n i t y . . T e x t . Res. J . 2 6 : 4 3 7 .  83.  Mann J . and Marrinan, H.J. 1956. The r e a c t i o n between c e l l u l o s e and heavy water. Trans. F a r . Soc. 52:481-497.  84.  M a r c h e s s a u l t , R.H. and Howsmon, J.A. 1957* Experimental e v a l u a t i o n of the l a t e r a l - o r d e r d i s t r i b u t i o n i n c e l l u l o s e . T e x t . Res. J . 22:30-41.  85.  Mark, H. 1940. I n t e r m i c e l l a r h o l e and tube system i n f i b r e s t r u c t u r e . J . Phys. Chem. 44:764-788.  Rayon s t r u c t u r e .  86.  . 1941. R e l a t i o n between c h a i n l e n g t h d i s t r i b u t i o n curve and t e n a c i t y . Paper Trade J . 113 (3):34-40.  87.  Marrinan, H.J. and Mann, J . 1954. A study by i n f r a - r e d spectroscopy of hydrogen bonding i n c e l l u l o s e . J . A p p l . Chem. 4:204-211.  88.  M e l l e r , A. 1949. J . Poly. S c i .  89.  Meyer, K.H. 1937. Uber den Bau des k r i s t a l l i s i e r t e n A n t e i l s der C e l l u l o s e . V. M i t t e i l . B e r i c h t e der Deutschen Chem. G e s e l l s c h a f t . B70:266-274.  90.  R e a c t i v i t y of f i b r o u s 4:619-628.  cellulose.  and Mark, H. 1929. Uber den Bau des k r i s t a l l i s i e r t e n A n t e i l der c e l l u l o s e I I . Chem. B2:115-145.  Z. Phys.  91 91•  ' and Badenhuizen, N.P. 1937. T r a n s f o r m a t i o n o f hydrate c e l l u l o s e i n t o n a t i v e c e l l u l o s e . Nature.  140i281-282.  92.  Mhatre, S.H. and P r e s t o n , J.M. 1 9 5 3 . observations on the r e l a t i o n s between the d e n s i t y , moisture a b s o r p t i o n s and c r y s t a l l i n i t i e s o f c e l l u l o s e f i b r e s . X I t h I n t e r n a t i o n a l Congress o f Pure and A p p l . Chem. S  o  m  e  _:I6I-I67.  93.  Monier-Williams, G.W. 1 9 2 1 . The h y d r o l y s i s o f c o t t o n c e l l u l o s e . J . Chem. Soc. 119:80V805.  94.  Morehead, F.F. 1 9 5 0 . U l t r a s o n i c d i s i n t e g r a t i o n o f c e l l u l o s e f i b r e s before and a f t e r h y d r o l y s i s . Text.  Res. J . 2 0 : 5 4 9 - 5 5 3 .  95.  Nelson, M.C. and Conrad, C M . 1 9 4 8 . Improvements i n the a c i d - h y d r o l y s i s method of determining the c r y s t a l l i n i t y o f c e l l u l o s e . T e x t . Res. J .  18:149-154.  96.  Nickerson, R.F. 1941. H y d r o l y s i s and c a t a l y t i c oxidation of c e l l u l o s i c materials. Hydrolysis of n a t u r a l , regenerated and s u b s t i t u t e d c e l l u l o s e s . Ind. Eng. Chem. 1 3 : 1 0 2 2 - 1 0 2 7 .  97«  98.  99* 100.  • 1 9 4 2 . H y d r o l y s i s and c a t a l y t i c o x i d a t i o n o f c e l l u l o s i c materials. H y d r o l y s i s o f mercerized cottons. I n d . Sng. Chem. 34:85-88. .  1 9 4 2 . H y d r o l y s i s and c a t a l y t i c o x i d a t i o n o f c e l l u l o s i c materials. Characterization of celluloses. Ind. Sng. Chem. _ 4 : 1 4 8 0 - 1 4 8 5 . • 1 9 5 1 . A c c e s s i b i l i t y o f c e l l u l o s e by formic a c i d e s t e r i f i c a t i o n . Text. Res. J . 2 1 : 1 9 5 - 2 0 2 . . 1951. celluloses.  The r e l a t i v e c r y s t a l l i n i t y of Adv. i n Carbohydrate Chem. _ 1 0 3 - 1 2 6 . :  101.  and H a b r l e , J.A. 1945- H y d r o l y s i s and c a t a l y t i c oxidation of c e l l u l o s i c materials. Determination o f s t r u c t u r a l components o f c o t t o n linters. Ind. Eng. Chem. _Z:1115-1118.  102.  and . 1 9 4 6 . H y d r o l y s i s and c a t a l y t i c o x i d a t i o n of c e l l u l o s i c m a t e r i a l s . Structural components o f v a r i o u s c e l l u l o s i c m a t e r i a l s . I n d . Eng. Chem. 38:299-301.  103.  and . 1947. C e l l u l o s e i n t e r c r y s t a l l l n e s t r u c t u r e . Study by h y d r o l y t i c method. Ind. Eng. Chem. 32:1507-1512.  92  104.  Nishikawa, S. and Ono, S. 1913. T r a n s m i s s i o n of X-rays through f i b r o u s , l a m e l l a r and g r a n u l a r substances. P r o c . Math .-Phys. S o c , Tokyo. £ • 1 3 1 - 1 3 8 , Chem. Abst. 2 : 8 8 8 .  105.  Nishikawa, S. 1914. The spectrum of X-rays obtained by means of l a m e l l a r or f i b r o u s substances. Proc. Math.-Phys. S o c , Tokyo. 2 2 9 6 - 2 9 8 , Chem. A b s t . J  2:888.  106.  Norkrans, B. 1950. I n f l u e n c e of c e l l u l o l y t i c enzymes from hymenomycetes on c e l l u l o s e p r e p a r a t i o n s of d i f f e r e n t c r y s t a l l i n i t y . P h y s i o l o g i a Plantarum  2:75-87.  107.  and Ranby, B.G. 1956. S t u d i e s of the enzymatic d e g r a d a t i o n of c e l l u l o s e . P h y s i o l o g i a Plantarum 2:198-211.  108.  O'Connor, R.T., Dupre, E.F. and Mitcham, D. 1958. A p p l i c a t i o n s of i n f r a - r e d a b s o r p t i o n spectroscopy to i n v e s t i g a t i o n s of c o t t o n and m o d i f i e d c o t t o n s . Text. Res. J . 2 8 : 3 8 2 - 3 9 2 .  109.  O t t , E. 1940. C e l l u l o s e d e r i v a t i v e s as b a s i c m a t e r i a l s for p l a s t i c s . Ind. Eng. Chem. 3£:l641-l647.  110.  , S p u r l i n , H.M. and G r a f f l i n , M.W. (ed.). 1954. C e l l u l o s e and c e l l u l o s e d e r i v a t i v e s . P a r t I . 2nd ed. I n t e r s c i e n c e Pub. I n c , New York. 509 PP»  111.  P r i e s t l e y , J.H. 1930. S t u d i e s i n the p h y s i o l o g y of cambial a c t i v i t y . I . C o n t r a s t e d types of cambial a c t i v i t y . New P h y t o l . £2(1):56-73.  112.  P r e s t o n , R.D. 1952. plant c e l l walls.  113.  The molecular a r c h i t e c t u r e of Chapman and H a l l , London. 206  pp.  , Hermans, P.H. and Weidinger, A. 1950. The c r y s t a l l i n e - n o n - c r y s t a l l i n e r a t i o i n c e l l u l o s e of b i o l o g i c a l i n t e r e s t . J . Exp. Bot. 1.344-352.  114.  P r e s t o n , J.M. and Tawde, G.P. 1956. Freezing point d e p r e s s i o n i n assemblages of moist f i b r e s . J . Text I n s t . Trans. 42:Tl54-l65.  115.  Reese, E.T., S i u , R.G.H. and L e v i n s o n , H.S. 1950. The b i o l o g i c a l d e g r a d a t i o n of s o l u b l e c e l l u l o s e d e r i v a t i v e s and i t s r e l a t i o n s h i p to the mechanism of c e l l u l o s e h y d r o l y s i s . J . Bact. 59:485-497.  93 116.  R i t t e r , G.J. and F l e c k , L.C. 1926. IX. Springwood and summerwood.  18:608-609.  Chemistry of wood. Ind. Eng. Chem.  117.  R i c h t e r , G.A., H e r d l e , L.E. and Gage, I.L. 1953. A c c e s s i b l e c e l l u l o s e as measured by s o r p t i o n of s u l f u r i c a c i d . Ind. Eng. Chem. 45:2773-2779.  118.  Rocha, H.J. 1930* F r a c t i o n a l p r e c i p i t a t i o n of actonesoluble a c e t y l c e l l u l o s e . Kolloidchem. B e i h e f t e . 20:230-248, Chem. A b s t . 24:2597.  119.  Rogovin, Z.A., K a r g i n , V.A. and Smirnov, V. 1941. E f f e c t of h i g h temperatures on f i b r e s . Tekstil. Prom. 3:40-42, Chera. A b s t . 32*6134.  120.  Roseveare, W.E. and Spaulding, D.W. 1955* E f f e c t of s w e l l i n g and supermolecular s t r u c t u r e on r e a c t i o n of c e l l u l o s e w i t h n i t r o g e n d i o x i d e . Ind. Eng. Chem.  42:2172-2175.  121.  Rowen, J.W. and P l y l e r , E.K. 1950. E f f e c t of d e u t e r a t i o n , o x i d a t i o n , and hydrogen-bonding on the i n f r a - r e d spectrum of c e l l u l o s e . J . Res. Nat. Bur. Stand. 4 4 S 3 1 3 - 3 2 0 .  122.  Sandeman, I . and K e l l e r , A. 1956. Crystallinity s t u d i e s of polyamides by i n f r a - r e d , s p e c i f i c volume and X-ray methods. J . P o l y . S c i . 12:401-435.  123.  Sakurada, I . and. Hutino,- K. 1936. Uber d i e i n t r a m i z e l l a r e Quellung der Z e l l u l o s e durch Wasser. K o l l .  Z.  2Z.346-351.  124.  Schwertassek, K. 1950. E x p l a n a t i o n of dyeing d e f e c t s i n c e l l u l o s e f i b r e s by measurements of i o d i n e s o r p t i o n , I I . R e l a t i o n of i o d i n e s o r p t i o n and c r y s t a l l i n i t y of c e l l u l o s e f i b r e s . M e l l i a n d T e x t i l b e r . 3 1 : 7 6 4 - 7 6 9 , Chem. A b s t . 45:5931.  125.  . 1951' Iodine s o r p t i o n of v i s c o s e f i b r e s and the v i s c o s e p r o c e s s . I I I . The r e l a t i o n of i o d i n e s o r p t i o n and the degree of c r y s t a l l i z a t i o n of c e l l u l o s e f i b r e s . M e l l i a n d T e x t i l b e r . 32:460-465*  126.  . 1952. V. Methods of determining i o d i n e a b s o r p t i o n , reduced i o d i n e a d s o r p t i o n , and normal mercerization. F a s e r f o r s c h U. T e x t i l t e c h . 3*87-95*  127*  * 1953* IX. The q u a l i t a t i v e a p p l i c a t i o n of the i o d i n e a b s o r p t i o n to f i b r e a n a l y s i s . F a s e r f o r s c h U. T e x t i l t e c h . 4 : l 8 l - l 8 7 , Chem. A b s t . 48:10335.  94  128.  S e g a l , L. and Jonassen, H.B. 1953« Evidence f o r i n t e r a c t i o n between c h l o r o f o r m and monoethylamine.  J . Am. Chem. Soc. Z4:3697-3699.  129.  S e g a l , L., Loeb, L. and C r e e l y , J . J . 1954. X-ray study o f the decomposition product of the ethylaminec e l l u l o s e complex. J . P o l y . S c i . 13:193-206.  130.  S i u , R.G.H. 1950. Mechanism o f m i c r o b i o l o g i c a l decomposition o f c e l l u l o s e . T e x t . Res. J .  20:281-288.  131.  . 1951. M i c r o b i a l decomposition of c e l l u l o s e . R e i n h o l d Pub. Corp., New York. 531 PP«  132.  Sobue, H. and Fukuhara, S. 1957. Study of a c c e s s i b i l i t y , degree of c r y s t a l l i n i t y and f i n e s t r u c t u r e o f c e l l u l o s e f i b r e by t h e i n f r a - r e d a b s o r p t i o n method. Kogyo Kagaku Z a s s h i 60:320-323.  133.  Sobue, H. and Minato, H. 1957. Pine s t r u c t u r e of c e l l u l o s e by X-ray method. Kogyo Kagaku Zahhi  60:327-331.  134.  S p o n s l e r , O.L. 1926. M o l e c u l a r s t r u c t u r e of p l a n t f i b r e s determined by X - r a y s . J . Gen. P h y s i o l .  2:677-695. 135.  S p u r l i n , H.M. 1938. Homogeneity and p r o p e r t i e s o f nitrocellulose. Ind. Eng. Chem. 30:538-542.  136.  S t e u r e r , E . 1940. Uber den E i n f l u s s des L i c h t e s auf C e l l u l o s e l S s u n g e n . Z. Phys. Chem. B47:127.  137.  and Hess, K. 1944. Uber d i e Vorgange b e i der Verformung und dem mechanochemischen Abbau hochpolymer S t o f f e durch Schwingraahlung. Z. Phys. Chem. A193-:  248-257.  138.  139.  T a n i g u c h i , E . 1952. V I I . The e f f e c t o f b l e a c h i n g on the s t r u c t u r e o f p u l p . J . J a p . F o r . Soc. ^4:^52357, Chem. A b s t . 47_:10837. 1953. IX. The e f f e c t s of b l e a c h i n g on the f i n e s t r u c t u r e of c e l l u l o s i c m a t e r i a l s . J . Yamagata  Agr. and For. Soc. 5:1-6, Chem. Abst.  42:1321.  140.  . 1953. V I I I . E f f e c t of cooking c o n d i t i o n and the b l e a c h i n g method on the f i n e s t r u c t u r e o f s u l f a t e pulp o f bamboo s t a l k . J . J a p . F o r . Soc. 35:128-133. Chem. A b s t . 48:6lll.  141.  . 1954. X. The change of c r y s t a l l i n e r e g i o n d u r i n g the s u l f a t e p u l p i n g . JJ..J; J a p . F o r . Soc. 36:133-135, Chem. A b s t . 42:'~~ 1321.  95  142.  . 1956. X I V . V a r i a t i o n s o f f i n e s t r u c t u r e i n P i n u s d e n s i f l o r a and P h y l l o s t a c h y s e d u l i s t h r o u g h t h e i r growth. J . J a p . Wood R e s . S o c . 2 : 1 5 2 - 1 5 7 . Chem. A b s t . 5 1 : 9 1 4 5 .  143.  . 1956. X I I . D e f o r m a t i o n o f f i n e s t r u c t u r e i n p u l p by h o t - a i r o r h o t - w a t e r t r e a t m e n t . Mokuzai G a k k a i s h i R e s . Soc. 2:148-152. Chem. A b s t . 51:9145.  144.  Tarkow, H. 1950. The a c c e s s i b i l i t y o f c e l l u l o s e . Tappi. 33:595-599.  145.  T r e i b e r , E. 1957. D i e Chemie d e r P f l a n z e n z e l l w a n d , S p r i n g e r - V e r l a g , B e r l i n . "5H pp.  146.  U r q u h a r t , A.R. and W i l l i a m s , A.M. 1925. Moisture r e l a t i o n s o f c o t t o n . The a b s o r p t i o n o f water by cotton mercerized without tension. J . Text. I n s t . 16:T155-166.  147.  V a l e n t i n e , L. 1956. A b s o l u t e c r y s t a l l i n i t i e s o f c e l l u l o s e from m o i s t u r e s o r p t i o n d e t e r m i n a t i o n s . Chem. and I n d . Nov. 1279-1280.  148.  W a k e l i n , J.H., V i r g i n , H.S. and C r y s t a l , E. 1959. Development and comparison o f two X - r a y methods f o r determining the c r y s t a l l i n i t y of c o t t o n c e l l u l o s e . In press.  149.  W a l s e t h , C.S. 1952. Occurrence o f c e l l u l a s e s i n enzyme p r e p a r a t i o n s from m i c r o o r g a n i s m s . Tappi. !5(5):228-233.  150.  . 1954. The i n f l u e n c e o f t h e f i n e s t r u c t u r e o f c e l l u l o s e on t h e a c t i o n o f c e l l u l a s e s . Tappi. 35(5);233-238.  151.  Ward, K. J r . 1950. C r y s t a l l i n i t y o f c e l l u l o s e and i t s s i g n i f i c a n c e f o r the f i b r e p r o p e r t i e s . Text. Res. J . 20:363-372.  152.  Wardrop, A.B. 1951* C e l l w a l l o r g a n i z a t i o n and t h e p r o p e r t i e s of the xylem. 1. C e l l w a l l o r g a n i z a t i o n and t h e v a r i a t i o n o f b r e a k i n g l o a d i n t e n s i o n o f t h e xylem i n c o n i f e r stems. A u s t . J . S c i . R e s . B4:391-414.  153.  • 1956. V. The d i s t r i b u t i o n and f o r m a t i o n o f t e n s i o n wood i n some s p e c i e s o f E u c a l y p t u s . A u s t . J . Bot. 4:152-166.  154.  and D a d s w e l l , H.E. 1948. The n a t u r e o f r e a c t i o n wood. A u s t . J . S c i . R e s . B l : 3 - l 6 .  96  155-  and . 1950. I I . The c e l l w a l l o r g a n i z a t i o n o f compression wood t r a c h e i d s . J . S c i . Res. B _ : l - 3 .  Aust.  156.  and . 1952. I I I . C e l l d i v i s i o n and c e l l w a l l formation i n c o n i f e r stems. A u s t . J . S c i . Res. B_>:385-398.  157.  and . 1955. IV. V a r i a t i o n s i n c e l l w a l l o r g a n i z a t i o n of t e n s i o n wood f i b r e s . A u s t . J . Bot. 3:177-189.  158.  Werner, K. and Engelmann, H. 1929. Some p r o p e r t i e s o f acetone-soluble c e l l u l o s e acetate. Angew Chem. 42:438-444.  159.  Whitaker, D.R. 1953. P u r i f i c a t i o n of Mvrothecium v e r u c a r i a c e l l u l a s e . A r c h . Biochem. and B i o p h y s . 43:253-268.  160.  Wijnman, C.F. 1954. I n f l u e n c e of heavy b e a t i n g of c o t t o n f i b r e s on moleculer l e n g t h and c r y s t a l l i n i t y . Tappi. 32:96-98.  161.  Wise, L.E. (ed.) 194-6. Wood c h e m i s t r y . 1 s t ed. R e i n h o l d Pub. Corp., New York. 900 pp.  162.  Wise, L.E., Murphy, M. and D'Addieco, A.A. 1946. C h l o r i t e h o l o c e l l u l o s e , I t s f r a c t i o n a t i o n and b e a r i n g on summative wood a n a l y s i s and on s t u d i e s on the hemicellulose. Paper Trade J . 122(2) :35-4-3.  163.  Wolfrom, M.L., Sowden, J.C. and L a s s e t t r e , E.N. 1939. The molecular s i z e o f methylated c e l l u l o s e . J . Am. Chem. Soc. 61:1072-1076.  164.  Z o b e l , B . J . and McElwee, R.C. 1958. V a r i a t i o n of c e l l u l o s e In l o b l o l l y p i n e . Tappi. 41(4):167-I7O.  165.  Z o b e l , B., Webb, C. and Henson, F. 1959. Core or j u v e n i l e wood o f l o b l o l l y and s l a s h pine t r e e s . Tappi. 4 2 ( 5 ) : 34-5-3 5 6 .  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0105951/manifest

Comment

Related Items