University of Southern California Dissertations and Theses

Method and technique in chromatographic separation of high polymers

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Method and technique in chromatographic separation of high polymers

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Content METHOD AMD TECHNIQUE IN CHROMATOGRAPHIC SEPARATION OF HIGH POLYMERS, fey S i Ju n g YeH A T h e s is P r e s e n te d to th e FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA I n P a r t i a l F u l f i l l m e n t o f th e R e q u ire m e n ts f o r th e D egree M a s te r o f S c ie n c e ( C h e m istry ) J a n u a r y 1957 UMI Number: EP41614 All rights reserved IN FO RM ATIO N TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Dissertation Publishing UMI EP41614 Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 0 6 - 1346 U N IV E R SITY O F S O U T H E R N C A L IF O R N IA GRADUATE SC H O O L UNIVERSITY PARK LO S A N G E L E S 7 d ‘5 1 u This thesis, written by s i mm ybh • under the guidance of h.t:S...Faculty Committee, and approved by all its members, has been pre sented to and accepted by the Faculty of the Graduate School, in partial fulfillment of the requirements for the degree of MASTER W SCIENCE .................................... - ................-JOHN-IX-GODKR.. . . Acting D ean ^ a n Date .... Faculty Committee u Chairman ACKNOW LEDGM ENT The a u th o r w ish e s t o th a n k D r. H. L. F r i s c h f o r t h e i' e n c o u ra g e m e n t and g u id a n c e w h ic h a lo n e h av e made t h e w r i t i n g o f t h i s t h e s i s p o s s i b l e . The a u th o r a l s o l i k e s t o th a n k D r. K. J . M ysels f o r t h e v a l u a b l e s u g g e s t i o n s and d i s c u s s i o n s i n c a r r y i n g o u t t h i s w o rk . TABLE OF CONTENTS CHAPTER PAGE I . INTRODUCTION ...................................................... 1 C l a s s i f i c a t i o n o f f r a c t i o n a t i o n m eth o d s a v a i l a b l e f o r h i g h p o ly m e rs . . . . . . . . . 2 A d v a n tag e s o f c h ro m a to g ra p h ic a d s o r p t i o n . . . . 1 + I I . LITERATURE RESEARCH ............................ 6 Review o f t h e work done i n t h i s f i e l d ..... 6 j i i C o n c lu s io n d e r i v e d fro m th e l i t e r a t u r e r e s e a r c h j I and p r o p o s e d p l a n o f i n v e s t i g a t i o n . . . . . . llj. | I I I . CHROMATOGRAPHIC ADSORPTION OF POLYSTYRENE . . . . 17 i | A n a ly s is o f f r a c t i o n s . . . . . . . . . . . . . 17 ! j E x p e r im e n ta l ............................ 20 ! R e s u l ts and d i s c u s s i o n s . . . . . . . . . . . . 30 IV . MEASUREMENT OF VISCOSITY AVERAGE MOLECULAR WEIGHT j \ ■ I OF POLYMER SOLUTIONS OF UNKNOW N CONCENTRATION. . 59 ! | I i P r i n c i p l e ......................................................... 59 j - I E x p e r im e n ta l and r e s u l t s . . . . . . . . . . . . . . 65 | V. SUMMARY AND CONCLUSIONS ........................................ . 70 BIBILIOGRAPHY 73 i LIST GF TABLES TABLE PAGE I . C l a s s i f i c a t i o n o f f r a c t i o n a t i o n m ethods a v a i l a b l e f o r high , p o ly m e rs . . • . • . . • • • 3 I I . A n a ly s is o f f r a c t i o n s e l u t e d w i t h t o lu e n e ( lo n g colum n ) . . . . . . . . . . . . . . . • 3^ I I I . A n a ly s is o f f r a c t i o n s e l u t e d w i t h to lu e n e ( s h o r t colum n ) . . . . . . . . . . . . . . . 3k IV . A n a ly s is o f f r a c t i o n s e l u t e d w i t h t e t r a l i n . . . 38 V. A n a ly s is o f f r a c t i o n s e l u t e d s t e p w i s e l y w i t h t h r e e s o l v e n t s . . ■ . « ~. . • . . . . . . . . . 1^-2 . V I. A n a ly s is o f f r a c t i o n s e l u t e d w i t h m ixed s o l v e n t s . j?0 j V I I . K and a v a l u e s f o r p o l y s t y r e n e a t 2 5 * 0 .1*C , . . « 66 / V I I I . S p e c i f i c v i s c o s i t y r a t i o s a t 2 5 * 0 .1 "C . . . . . . 68 IX . G o m p a risio n b e tw e e n c a l c u l a t e d and e x p e r im e n ta l LIST OP FIGURES - FIGURE PAGE 1 . D iagram o f th e a d s o r p t i o n colum n .- 25 2* C hrom atogram o f p o l y s t y r e n e e l u t e d w i t h t o l u e n e (lo n g colum n) ... • . • « . . . • . . . 35 3 . C hrom atogram p f p o l y s t y r e n e e l u t e d w i t h t o l u e n e ( s h o r t colum n) . . . . « . . . . . ... . . 35 4 . C hrom atogram o f p o l y s t y r e n e e l u t e d w i t h t e t r a l i n . 39 5 . . C hrom atogram o f p o l y s t y r e n e e l u t e d s t e p w i s e l y w i t h t h r e e s o l v e n t s . . ., . . . .. . . . . . . . . 44 6a* T o ta l w e ig h t v s . M v p l o t o f F i g . 5 * . • . . . . . 45 6 b . dW/dMy v s . My p l o t o f F i g . 6 a ..................... . . . 4 6 7 . C hrom atogram o f p o l y s t y r e n e e l u t e d w i t h m ixed s o l v e n t s . . .. . . . . . . . . . . . . . . . . 52 j 8 a . T o ta l w e ig h t v s . My p l o t o f F i g . 7; . . . . . . . . 53 i . | 8 b . dW/dMy v s . My p l o t o f F i g . 8 a . . . . . . . . . . 54 CHAPTER I INTRODUCTION A m o le c u le o f a p o ly m e r ic s u b s ta n c e i s fo rm ed fro m a g iv e n num ber o f s t r u c t u r a l u n i t s c l o s e l y r e l a t e d t o t h e m o le c u le s o f t h e monomer fro m w h ic h t h e p o ly m e r i s d e r i v e d . B o th n a t u r a l and s y n t h e t i c h i g h p o ly m e rs a r e m ix tu r e s i n t h e s e n s e t h a t t h e m o le c u le s may d i f f e r i n s i z e ( i . e . d e g re e o f p o l y m e r i z a t i o n ) , i n sh a p e ( i . e . d e g r e e o f b r a n c h in g o r c r o s s l i n k i n g ) and e v en i n c h e m ic a l c o m p o s itio n ( i . e . i n c o - \ i j [p o ly m e rs ). I n o r d e r t o i n t e r p r e t a g iv e n p r o p e r t y o f a ! I ' i jpolym er we a r e f o r c e d t o p ro c e e d by c o n s i d e r i n g th e e o n t r i - I | j i b u ti o n o f e a c h m o le c u la r s p e c i e s t o t h a t p r o p e r t y ; t h e f i n a l i . . ! ; r e s u i t b e in g o b t a i n e d by summing th e c o n t r i b u t i o n fro m a l l I < - ■ ■ ■ ■ j s p e c i e s p r e s e n t . i I I t i s t h e r e f o r e o f u tm o s t im p o r ta n c e i n t h e s tu d y o f ]a p o ly m e ric sy ste m t o know t h e m o le c u la r w e ig h t d i s t r i b u t i o n i ■ ' | jof t h e p o ly m e r a s a lm o s t a l l p h y s i c a l and c h e m ic a l p r o p e r t i e s * I !©f t h e p o ly m e r a r e fo u n d a s some ty p e o f s t a t i s t i c a l mean j ! • I jv a lu e o f t h e p r o p e r t i e s o f t h e i n d i v i d u a l m o le c u le s . The jd e t e r m i n a t i o n o f m o le c u la r w e ig h t d i s t r i b u t i o n f u n c t i o n i s | [th u s one o f t h e m ain p ro b le m s i n h ig h p o ly m er c h e m is tr y and jhas a c c o r d i n g l y b e e n a t t a c k e d b y a g r e a t num ber o f w o r k e r s . I h p r i n c i p l e , t h e m o le c u la r w e ig h t d i s t r i b u t i o n o f a p o ly m er may be d e r i v e d fro m s t a t i s t i c a l c o n s i d e r a t i o n s by I [ c o n s id e r in g t h e c ir c u m s ta n c e s w h ic h c o n t r o l th e m o le c u la r j g ro w th u n d e r g iv e n c o n d i t i o n s o f p o l y m e r i z a t i o n i n co n ju n ct-? L i-on-w -i-th--the-w eli-es1rabl-i-shed— te n d e n c y — o f — ehemi-cal--r-ea-ctl-ons t o p r o c e e d i n a random m an n e r. H ow ever, t h e m o st common way o f o b t a i n i n g t h e m o le c u la r w e ig h t d i s t r i b u t i o n h a s b e e n a c h ie v e d b y t h e e x p e r im e n ta l a p p ro a c h c o n s i s t i n g o f s e p a r a t i o n o f t h e p o ly m e rs by f r a c t i o n a t i o n and r e c o n s t r u c t i o n o f t h e d i s t r i b u t i o n c u rv e fro m t h e am ount and t h e a v e r a g e m o le c u la r w e ig h t o f e a c h f r a c t i o n . Thus f r a c t i o n a t i o n i s a f u n d a m e n ta l p r o c e d u r e f o r t h e d e t e r m i n a t i o n o f t h e m o le c u la r w e ig h t d i s t r i b u t i o n o f t h e p o ly m e r . B e s i d e s , f r a c t i o n a t i o n i s a n e c e s s a r y p r e l i m i n a r y s t e p i n t h e a p p l i c a t i o n o f v i s c o s i t y m easurem ent t o ! t h e d e t e r m i n a t i o n o f t h e v i s c o s i t y a v e ra g e m o le c u la r w eig h t! j o f th e p o ly m e r, and i t m akes th e c o r r e l a t i o n o f o t h e r j j p h y s i c a l p r o p e r t i e s w i t h t h e a v e r a g e m o le c u la r w e ig h t i | d i s t r i b u t i o n p o s s i b l e . I | I n t h e l i g h t o f t h e f o r e g o i n g , t h e r e h a s b e e n a | s t e a d i l y i n c r e a s i n g r e c o g n i t i o n o f t h e im p o rta n c e o f t h e | f r a c t i o n a t i o n o f p o ly m e rs b o th i n r e s e a r c h and f o r i n d u s t r i - | I a l c o n t r o l . j I | I . C l a s s i f i c a t i o n o f F r a e t i o n a t i o n M ethods i i A v a i l a b l e f o r H igh P o ly m e rs ! ! ! The f r a c t i o n a t i o n m ethods t h u s f a r d e v e lo p e d may b e | I i ! c l a s s i f i e d on t h e b a s i s o f t h e s e p a r a t i o n p r i n c i p l e and I ! , i j sum m arized i n t h e t a b l e shown b e lo w .x (T a b le I ) The m ost | ! j jcommon m ethod i s th e f r a c t i o n a l p r e c i p i t a t i o n m eth o d . T h is; i ! ~ J- L. G rag g , and H. H am m erschlag, Chem. R ev. 39 79 (19*4-6). “ 3 TABLE X CLASSIFICATION OF FRACTIONATION METHODS AVAILABLE FOR POLYMERS M ethods P r i n c i p l e on i^hich s e p a r a t i o n i s b a s e d I . S o l u b i l i t y m ethod | 1 . F r a c t i o n a l p r e c i p i t a t i o n S o l u b i l i t y d e c r e a s e s w ith i n c r e a s i n g m o le c u l a r w e ig h o f p o ly m e r. a . By a d d i t i o n o f p r e c i p i t a n t b . By c o o li n g 2 . F r a c t i o n a l s o l u t i o n a . S o lv e n t o f v a r i n g c o m p o s itio n ! b . V a rin g t e m p e r a t u r e i 3 . D i s t r i b u t i o n b e tw e e n two D i s t r i b u t i o n c o e f f . deJ im m is ib le s o l v e n t s p en d s on M. W. o f p o ly m e r. I I . R ate o f s o l u t i o n m ethod | ( D i f f u s i o n i n t o a s i n g l e j s o l v e n t ) S m all m o le c u le d i f f u s e \ f a s t e r . j I I I . U l t r a c e n t r i f u g e m ethod S e d im e n ta tio n v e l o c i t y I i n c r e a s e s w ith M.W. o f j p o ly m e r. ! TV. U l j s r a f i l t r a t i o n th r o u g h g ra d e d mem branes S ie v in g a c t i o n . V. C h ro m a to g ra p h ic a d s o r p t i o n P r e f e r e n t i a l a d s o r p t i o n p r o e e d W e T s ^ h b w e v e r , v e r y ”l a b o r i o u s and r e q u i r e s a l s o f a i r l y l a r g e am ounts o f s u b s t a n c e . F u r th e r m o r e , s h a r p s e p a r a t i o n s a r e n e v e r a c h ie v e d , and r e l i a b l e r e s u l t s r e q u i r e tim e consum ing, f r a c t i o n a t i o n and r e f r a c t i o n a t i o n i n t o a l a r g e num ber o f c u t s . S e v e r a l more e l e g a n t p h y s i c a l m e th o d s, m ethod I I t h r o u g h IV i n t h e t a b l e shown a b o v e , h a v e b e e n p ro p o s e d , b u t t h e s e r e q u i r e r a t h e r e x t e n s i v e a p p a r a t u s and s p e c i a l t e c h n i q u e . ?I I . A d v a n ta g e s o f t h e C h ro m a to g ra p h ic A d s o r p tio n M ethod C h ro m a to g ra p h ic a d s o r p t i o n i s a u s e f u l m ethod f o r s e p a r a t i n g m ix tu r e s i n t o t h e i r c o m p o n e n ts; e v e n c l o s e l y r e l a t e d s u b s ta n c e s h a v e o f t e n b e e n s u c c e s s f u l l y s e p a r a t e d , | The m ethod c o n s i s t s i n f i l t e r i n g t h e s o l u t i o n c o n t a i n i n g | th e m ix tu r e s t o b e s e p a r a t e d th r o u g h a colum n o f an a d s o r b e n t , i | d e v e lo p in g t h e chro m ato g ram by w a sh in g w ith p u r e s o l v e n t , | and e l u t i n g v a r i o u s p a r t s o f th e colum n s e p a r a t e l y t o t i r e c o v e r t h e a d s o rb e d m a t e r i a l . The p r i n c i p l e on w h ic h t h e s e p a r a t i o n i s b a s e d i s p r e f e r e n t i a l a d s o r b t i o n ; n a m e ly , th e co m ponents p r e f e r e n t i a l l y a d s o rb e d a r e fo u n d i n th e u p p e r | p a r t s o f t h e colum n, t h o s e more w e a k ly a d s o rb e d i n t h e ! lo w e r p a r t s , and t h o s e m ost w e a k ly a d s o r b e d i n th e f i l t r a t e s . E l u t i o n r e v e r s e t h e p r o c e s s o f a d s o r p t i o n , t h a t i s , i t c a u s e s t h e s u b s ta n c e s t o p a s s fro m t h e a d s o rb e d l a y e r i n t o s o l u t i o n a g a i n . I t c an be c a r r i e d o u t by f i l t e r i n g t h e e l u t a n t th r o u g h t h e colum n and c o l l e c t i n g th e f i l t r a t e s i n 5 a s e r i e s o f c o n t a i n e r s a s t h e b a n d s a r e w ashed o u t o f t h e colum n. The a d v a n ta g e s o f t h i s te c h n iq u e o v e r t h e o t h e r s a r e t h a t i t i s s im p le t o c a r r y o u t w i t h r e l a t i v e l y a s m a ll am ount o f t h e p o ly m e rs u n d e r c o n s i d e r a t i o n , and i t m ig h t b e a b l e t o y i e l d s h a r p f r a c t i o n s by th e p r o p e r c h o ic e o f a d s o r b e n t - s o l v e n t p a i r . I f one c o n s i d e r s t h e f a c t t h a t th e a p p l i c a t i o n o f c h ro m a to g ra p h ic t e c h n i q u e t o th e s e p a r a t i o n s o f n a t u r a l l y o c c u r r i n g p o ly m e rs , e . g . p r o t e i n s and a m in o a c id s , a r e so s u c c e s s f u l , i t i s w o rth w h ile t o t r y t h e a p p l i c a t i o n o f c h ro m a to g ra p h ic a d s o r p t i o n t o th e s y n t h e t i c p o ly m e rs . CHAPTER I I j LITERATURE RESEARCH i i ! I . R eview o f t h e Work Done i n T h is F i e l d i ! ' ' i i * j I t i s r a t h e r a r e m a r k a b le f a c t t h a t v e r y few p a p e r s j | d e a l i n g w i t h c h ro m a to g ra p h ic s t u d i e s o f h ig h p o ly m e rs o th e r t h a n n a t u r a l l y o c c u r r i n g p o ly m e rs h a v e b e e n p u b l i s h e d , ! ■ The e a r l i e s t w ork on th e s tu d y o f t h e c h ro ra a to g ra - | p h i c p r o c e s s a p p l i e d t o t h e f r a c t i o n a t i o n o f h i g h p o ly m e rs I • I was c a r r i e d o u t i n 1936 by Mark and S a i t o . 2 I n an a tt e m p t , ‘ ' i t o f r a c t i o n a t e c e l l u l o s e a c e t a t e , b lo o d c h a r c o a l was u s e d ! I ■ ; i a s a d s o r b e n t and a c e to n e a s s o l v e n t . A g l a s s t u b e , 3 cm. j | i n d ia m e te r and *+2 cm. i n l e n g t h , was f i l l e d w i t h t h r e e j i I ; l a y e r s (10 g r . e a c h ) o f pow dered c h a r c o a l (th e l a y e r s w e re j j s e p a r a t e d fro m e a c h o t h e r by ro u n d p i e c e s o f c l o t h ) . 30 I I l m l. o f 0 .5% s o l u t i o n o f c e l l u l o s e a c e t a t e i n a c e to n e was j j I ! f i l t e r e d th r o u g h t h i s colum n u n d e r p r e s s u r e . A f t e r w ash - j I j i ! i n g t h e ch ro m ato g ram w i t h a c e t o n e , e a c h l a y e r o f c h a r c o a l j \ ' ! j was t h e n d r i e d , sh a k e n w ith 50 m l. o f d io x a n e f o llo w e d by j i ■ i | s t a n d in g f o r one d a y . Then t h e s o l u t i o n w ere s e p a r a t e d j | and e v a p o r a te d a t 60°C . t o a d r y r e s i d u e . The r e s u l t i n g j ; f r a c t i o n s w ere fo u n d t o d i f f e r i n m o le c u la r w e ig h t ( d e t e r - ; I m ined v i s c o m e t r i c a l l y ) b u t n o t i n t h e a c e t y l c o n t e n t . j | L e v i and G e r a ,3 i n 1937, fo u n d t h a t c e l l u l o s e | I i } I ! j I | 2 H. Mark and G. S a i t o , M o n tash 68 239 (1936 ) ; j 3 G. L e v i and A. G e ra , OrAZZ. Chim. I t a l . 67 719 | (1 9 3 7 ) d i a c e t a t e c o u ld be c h r o m a to g r a p h ic a ll y f r a c t i o n a t e d . They s u g g e s te d t h e u s e o f 2 :1 e t h e r - a l e o h o l m ix tu r e a s a s o l v e n t f o r th e c h ro m a to g ra p h ic f r a c t i o n a t i o n o f c e l l u l o s e n i t r a t e w i t h b lo o d c h a r c o a l a s a d s o r b e n t . k h a n d le r h a s c a r r i e d o u t a s t u d y o n t h e c h ro m a to g r a p h ic f r a c t i o n a t i o n o f s y n t h e t i c e l a s t o m e r s . T h ree e l a s t o m e r s , GR-S, P e rb u n a n and V i s t a n e x , w ere f r a c t i o n e d b y f i l t r a t i o n o f t h e i r s o l u t i o n s i n t o l u e n e w h ic h c o n t a i n s j u s t to o l i t t l e m e th a n o l t o p r e c i p i t a t e t h e e la s t o m e r s th r o u g h a tu b e c o n t a i n i n g t h r e e l a y e r s o f an a d s o r b e n t m ix tu r e s o f 75% g a s b l a c k and 25% a c t i v e g r a n u l a t e d c a rb o n ! b l a c k . The colum n was w ashed w ith t h e same s o l v e n t . Then t h r e e l a y e r s w ere s e p a r a t e d and w ashed w i t h t h r e e s o l v e n t s , t o l u e n e , c a r b o n t e t r a c h l o r i d e and b e n z e n e . I t was con c lu d e d t h a t i n low c o n c e n t r a t i o n an e la s t o m e r o f low m ole c u l a r w e ig h t i s a d s o rb e d f i r s t , b u t i n h i g h e r c o n c e n tr a t i o n i t i s a d s o rb e d l a s t . The p e r c e n t a g e o f e la s to m e r a d s o rb e d i n c r e a s e s w i t h i n c r e a s e i n c o n c e n t r a t i o n o f th e s o l u t i o n . I n 19*+8, some p r e l i m i n a r y e x p e r im e n ts on t h e a d s o r p t i o n a n a l y s i s o f h ig h p o ly m e rs h a v e b e e n c a r r i e d o u t! I by C la e s s o n and C la e s s o n 5 i n o r d e r t o i n v e s t i g a t e t h e i i j p o s s i b i l i t i e s o f u s i n g f r o n t a l a n a l y s i s i n t h e s tu d y o f h ig h p o ly m e r s . The e x p e r im e n ts w ere c a r r i e d o u t w i t h n i t r o c e l l u l o s e , p o l y v i n y l a c e t a t e and s y n t h e t i c r u b b e r . * * I . L a n d le r , Com pt. R end. 225 23b (1 9 ^ 7 ) 5 I . C la e s s o n and C la e s s o n S . , P h v s . R ev . 7R 1221 (1 9 ^8 ) 8 The s o l u t i o n w as f o r c e d th r o u g h a colum n w i t h e h a r e o a l a s a d s o r b e n t , and t h e c o n c e n t r a t i o n o f t h e e f f l u e n t was d e t e r m ined c o n t i n u o u s l y w ith a m i c r o - i n t e r f e r e n c e r e f r a c t o m e r . i t was fo u n d t h a t t h e r e w ere p o s s i b i l i t i e s o f o c c u r r e n c e o f d i f f e r e n t d i s c r e t e f r a c t i o n s and t h e f r a c t i o n s fro m t h e a d s o r p t i o n a n a l y s i s w e re l e s s p o l y — d i s p e r s e t h a n t h e o r i g i n a l s o l u t i o n s . A s e p a r a t e s tu d y ^ showed t h a t t h e am ount a d s o rb e d d e c r e a s e s w ith i n c r e a s e i n m o le c u la r w e ig h t o f t h e p o ly m e rs and t h e same i s t r u e f o r t h e r a t e o f ad so rp j- | t i o n . B o th t h e s e e f f e c t s s u g g e s t t h a t t h e h ig h m o le c u la r i | s p e c i e s w i l l be e x p e c te d i n t h e f i r s t f r a c t i o n s m aking i t i i i j p o s s i b l e t o f r a c t i o n a t e p o ly m e rs a c c o r d in g t o m o le c u la r j w e ig h t. | The t h e o r e t i c a l t r e a t m e n t o f f r o n t a l a n a l y s i s , s i | e s p e c i a l l y t h e r e l a t i o n b e tw e e n s p e c i f i c r e t e n t i o n volum e i j j and m o le c u la r w e ig h t d i s t r i b u t i o n h a s b e e n g iv e n by 1 j C l a e s s o n ? who r e a c h e d t h e c o n c l u s i o n t h a t i f t h e f r o n t a l | a n a l y s i s d ia g ra m i s e x t r a p o l a t e d t o z e r o c o n c e n t r a t i o n , i t i ! I w i l l g iv e an u p s i d e down p i c t u r e o f t h e m o le c u la r w e ig h t ! ' d i s t r i b u t i o n f u n c t i o n . S e v e r a l e x p e r im e n ts w ith f r a c t i o n s j 5 and s y n t h e t i c m ix tu r e s w e re made t o c o n firm t h e c o n c l u s i o n . I i ; The e x p e r im e n ts w ere d one w i t h p o ly m e th y l m e t h a c r y l a t e and | ! j n i t r o c e l l u l o s e a t v a r i o u s c o n c e n t r a t i o n i n a c e to n e and i n I | a c e to n e m e th a n o l m i x t u r e s . I n o r d e r t o g e t h ig h s e l e c t i v i t y ! t ; ! . i 1 i n l a r g e am ount o f a d s o r b e n t and a s e r i e s o f c o u p le d . C la e s s o n and I . C la e s s o n , A rk . Kem i. M in. G e o l. I i£ A No. 5 (19M O 7 S . C la e s s o n , A rk . Kemi. M in. G e o l. 26k No. 2*+ (1 9 ^ 9 ) f i l t e r s w e re u s e d and v e r y d i l u t e s o l u t i o n and low r a t e o f flo w w e re p r e f e r r e d . I t i s p o i n te d o u t by C la e s s o n him s e l f t h a t t h i s f r o n t a l a n a l y s i s te c h n iq u e i s n o t an a b s o l u t e o n e , s i n c e i t i s n e c e s s a r y t o d e te r m in e t h e r e l a t i o n b e tw e e n s p e c i f i c r e t e n t i o n volu m e and t h e m o le e u - i l a r w e ig h t by some o t h e r m e th o d s. H ow ever, t h i s t e c h n iq u e i s u s e f u l a s a com plem ent t o o t h e r f r a c t i o n a t i o n p r o c e d u r e s . A n o th e r e x p e rim e n t ® c a r r i e d o u t a t a s e r i e s o f c o n c e n tr a t i o n s down t© 0.G 2% and e x t r a p o l a t e d t o z e r o c o n c e n t r a t i o n | I w i t h a s o l u t i o n o f p o ly m e th y l m e t r a c r y l a t e i n a c e to n e and I | a s o l u t i o n o f p o l y v i n y l a c e t a t e i n a c e to n e showed t h a t t h e I I S c u r v e s o b t a i n e d by f r o n t a l a n a l y s i s p r o v i d e i n f o r m a t i o n i I | a b o u t t h e c o m p o s itio n o f h i g h poly m er s o l u t i o n s , and th e I a g re e m e n t w i t h o t h e r m eth o d s o f d e te r m i n i n g m o le c u la r 1 w e ig h t d i s t r i b u t i o n w h ic h w ere c a r r i e d o u t by Kinell^ on t « I I j t h e f r a c t i o n a l p r e c i p i t a t i o n and v i s c o s i t y m easu rem en t was 1 v e r y g o o d • i * li • A d i f f e r e n t a p p ro a c h t o t h e s tu d y o f t h e c h ro ra a to - ! | g r a p h i c a d s o r p t i o n s o f h ig h p o ly m er was r e p o r t e d by | B a n n i s t e r , P h i l l i p s and Williams-*-^ who c r i t i c i z e d t h e j i ' I j f r o n t a l a n a l y s i s c a r r i e d o u t by C la e s s o n by s a y in g t h a t i t | ! ‘ "' ' ! 1 d i d n o t f r a c t i o n a t e t h e p o ly m e r. The f r a c t i o n a t i o n | i | &S. C la e s s o n , D i s c u s s . F a r a d . S o c . No. 7 321 (1 9 ^ 9 ) ! 9 p . K i n e l l . A c ta Chem. S c a n d . 1 832 (1 9 ^ 7 ) ! / i . _ - r - r t — r j m m [ j | 10 D. B a n n i s t e r , C. P h i l l i p s and R. W illia m s , A n a l. Chem. 26 l b $ l (1 9 5 ^) p ro p o s e d b y t h e s e a u t h o r s w as an a p p l i c a t i o n o f g r a d i e n t e l u t i o n . - 1 -1 12 i n t h i s t e c h n iq u e th e d i f f e r e n t m o le c u la r w e ig h t f r a c t i o n s o f s i l i c o n e p o ly m e rs w h ic h a r e known t o be l i n e a r w ere a d s o rb e d o n to t h e a d s o r b e n t . The d e v e lo p ment o f t h e zone commences w i t h th e p o o r s o l v e n t b u t e l u t i o n i s c a r r i e d on w i t h i n c r e a s i n g m ore p o w e rf u l e l u t i n g s o l v e n t f o r t h e s u b s t a n c e s . A good s o l v e n t m ust be s o c h o se n t h a t i t w i l l e l u t e t h e s u b s ta n c e u n d e r c o n s i d e r a t i o n fro m t h e colum n q u a n t i t a t i v e l y and w i t h v e r y s m a ll r e t e n t i o n . P r e l i m i n a r y t e s t s showed t h a t f o r s i l i c o n e p o ly m e rs a lu m in a and s i l i c a g e l w ere u n s u i t a b l e a d s o r b e n t s i | b e c a u s e no s o l v e n t w ould e l u t e th e h i g h m o le c u la r w e ig h t p o ly m e rs o u t . H ow ever, i f s i l i c o n e s w ere a d s o r b e d o n to a n im a l c h a r c o a l t h e y w ould be q u a n t i t a t i v e l y e l u t e d by d i e t h y l e t h e r . I t was fo u n d t h a t n o n e o f th e m a t e r i a l , e v en o f th e h ig h m o le c u la r w e ig h t, h a d b e e n i r r e v e r s i v e l y a d s o r b e d . I n p r a c t i c e , 3 . 5 g r . o f s i l i c o n e p o ly m er f l u i d was a p p l i e d t o t h e to p o f th e colum n, 3 5 cm. i n l e n g t h and 1 .5 cm. i n d i a m e t e r , w h ic h was p r e p a r e d i n m e th a n o l, a p o o r s o l v e n t . The e l u t i o n w as commenced w i t h a b e t t e r s o l v e n t , e t h a n o l and t h e e f f l u e n t was c o l l e c t e d on a tim e b a s i s . The flo w r a t e was m a in ta in e d a t 5~10 nil. / h r . . A f t e r 230 m l. had flo w e d fro m t h e colum n, t h e s o l v e n t was chang ed H R . W illia m s and A. T i s e l i u s , A c ta Chem. S c a n d . 6 826 (1952) ________ 12 R. W illia m s . A n a ly s t 77 905 (1952)_________________ t o a 5 0 -5 0 m ix tu r e o f d i e t h y l e t h e r and e t h a n o l . The s o l v e n t w a s, a g a i n , c h an g ed t o 2 5 -7 5 m ix tu r e o f d i e t h y l e t h e r and e t h a n o l a f t e r a f u r t h e r 60 m l. o f e f f l u e n t had ; flo w e d fro m t h e colu m n. I t was f i n a l l y c h an g ed t o p u r e j e t h e r a f t e r 60 m l. o f e f f l u e n t had b e e n c o l l e c t e d . As t h e f r a c t i o n s w e re e l u t e d b y d i f f e r e n t s o l v e n t s th e v i s c o s i t y o f th e f r a c t i o n c o u ld n o t b e d e te r m in e d d i r e e t l y . The s o l v e n t was d i s t i l l e d o f f and t h e w e ig h t o f t h e p o ly m e r i n e a c h f r a c t i o n was d e te r m in e d by d i r e c t w e ig h in g . E ach f r a c t i o n o f t h e p o ly m er was t h e n d i s s o l v e d i n t o l u e n e and ; t h e v i s c o s i t y o f t h e s o l u t i o n was m ea su re d a t 1 5 ° C. by an © stw ald v i s c o m e te r . The v i s c o s i t y m easu rem ent showed t h a t i j s i l i c o n e p o ly m e rs w ere e l u t e d o u t i n o r d e r o f i n c r e a s i n g m o le c u la r w e i g h t. I t was c o n c lu d e d t h a t t h i s t e c h n i q u e , w h ic h d e p e n d s on t h e c h o ic e o f s o l v e n t g r a d i e n t i s t h e m o st | s u i t a b l e m ethod f o r t h e f r a c t i o n a t i o n o f s i l i c o n e p o ly m e r s . f i A n a l y s i s o f m ix tu r e s o f v a r i o u s s i l i c o n e p o ly m e rs w ith i i ; 1 d i f f e r e n t m o le c u la r w e ig h ts h a s b e e n t r i e d . The r e s u l t s ! | showed t h a t a v e r y h i g h c o n c e n t r a t i o n o f low m o le c u la r j w e ig h t p o ly m e rs a p p e a re d i n t h e f i r s t few f r a c t i o n s . i | I t i s v e r y i n t e r e s t i n g t o n o te t h e f a c t t h a t no ! a tte m p t h a s b e e n made t o a p p ly t h e c h ro m a to g r a p h ic s tu d y j j t o p o l y s t y r e n e u n t i l , r e c e n t l y , B ak er and Williams1^ u s e d j p o l y s t y r e n e a s a t e s t i n g m a t e r i a l t o d e v e lo p a new i j 13 C. B ak er and R. W illia m s , J . Chem. S o c . J u l y L235-2__(.1.9-5-6.)_ _ _ — ---------------------------------------------------------------------------- 1 z c h ro m a to g r a p h ie t e c h n iq u e b a s e d on t h e e q u i l i b r a t i o n o f s u b s ta n c e s b e tw e e n a s t a t i o n a r y p r e c i p i t a t e d p h a se and a m oving s o l u t i o n . The e s s e n t i a l r e q u i r e m e n t s t o be met f o r i t h i s new t e c h n i q u e a r e ; j I ; 1 . A colum n o f i n e r t m a t e r i a l ( g l a s s b e a d s ) k e p t i n a t e m p e r a t u r e j a c k e t w h ic h i s d e s ig n e d i n su c h a way t h a t a t t h e to p o f i t i s h e ld a t a i h i g h e r te m p e r a tu r e t h a n a t th e b o tto m . | I 2 . E l u t i o n o f th e p o ly m er d e p o s i t e d on t h e t o p o f j t h e colum n. j j 3 . S u b s ta n c e s u n d e r c o n s i d e r a t i o n must h a v e a i j p o s i t i v e t e m p e r a t u r e c o e f f i c i e n t o f s o l u b i l i t y . The g e n e r a l p r o c e d u r e c an b e sum m arized a s f o l l o w s . The colum n u s e d i s a g l a s s t u b e , 35 em. i n l e n g t h and 2 .b cm. i n e x t e r n a l d i a m e t e r , i n w h ic h t h e g l a s s b e a d s w e re p a ck e d a s a s l u r r y i n t h e p o o r s o l v e n t . N ear t h e b o tto m I o f th e g l a s s s o l u t i o n i s f i t t e d a s i n t e r e d g l a s s d i s c , and t h e colum n i s t a p e r e d a t th e b o tto m t o a f i n e c a p i l l a r y ; w h ic h c o n t r o l s th e r a t e o f flo w o f s o l v e n t th r o u g h th e I colum n a s t h e g l a s s b e a d s p e r m it to o r a p i d f l o w . The J t e m p e r a tu r e j a c k e t i s a c y l i n d r i c a l alum inum b lo c k i n w h ic h j j h a s b e e n d r i l l e d o u t a h o l e m aking a c lo s e f i t w ith t h e I i i e x t e r n a l d i a m e t e r o f t h e co lu m n . The t o p o f t h e j a c k e t i s j h e a t e d by an e l e c t r i c a l l y h e a t e d s p i r a l i n su c h a way t h a t j t h e b o tto m o f t h e colum n i s h e ld c l o s e t o 1 0 ° C. , t h e to p I j a t 6 o ° C 6 5 ° C . . 300 mg. o f p o l y s t y r e n e w e re d i s s o l v e d i n j 10 m l. o f m ethy l e t h y l k e t o n e . The s o l u t i o n was added t o 13. T 3 0 g r . o f g l a s s b e a d s and th e s o l v e n t was e v a p o r a te d w ith ; a h o t a i r f a n . Thus p o l y s t y r e n e c o a t s t h e g l a s s a s a t h i n f i l m . A f t e r t h e s e b e a d s w e re added t o t h e to p o f t h e colum n, e l u t i o n was commenced w i t h p o o r s o l v e n t , t h e n g r a d u a l l y ch an g ed t o t h e b e t t e r o n e . The p o ly m e r s o l u t i o n s c o l l e c t e d i n t h e t e s t tu b e w ere t r a n s f e r r e d i n th e b e a k e r and f l o o d e d q u i c k l y w i t h a n e x c e s s am ount o f m e th a n o l t o fo rm a s u s p e n s io n o f p o l y s t y r e n e . The p o l y s t y r e n e p r e c i p i t a t e d was d e c a n te d and w ashed w ith m e th a n o l t h o r o u g h ly [ I and f i n a l l y t r a n s f e r r e d t o a w a tc h g l a s s o f known w e i g h t. ; ' I J The w a tc h g l a s s was w e ig h ed a g a i n a f t e r e v a p o r a t i n g t h e j i s o l v e n t . I n t h i s way t h e am ount and h e n c e t h e c o n c e n t r a - I ■ | t i o n o f t h e po ly m er i n e a c h f r a c t i o n was f o u n d . The i i | f r a c t i o n s w e re a n a ly z e d by m easu rem en t o f t h e i r s p e c i f i c | v i s c o s i t y (0,5% s o l u t i o n i n t o l u e n e ) u s i n g an O stw ald \ v i s c o m e t e r . A c a l i b r a t i o n c u rv e o f v i s c o s i t y v s . num ber j I I I i ; a v e r a g e m o le c u la r w e ig h t was s e t up by u s i n g some o f t h e I I ! I f r a c t i o n a t e d m a t e r i a l s . From t h i s c a l i b r a t i o n and t h e i i n f o r m a t i o n fro m t h e f r a c t i o n a t i o n on th e colum n a cu rau la- t t i v e p e r c e n t a g e c o m p o s itio n a g a i n s t m o le c u la r w e ig h t c h a r t j was o b t a i n e d . T h u s, c o n c l u s i v e r e s u l t s h a v e b e e n r e p o r t e d : I : ! j b y t h e s e a u t h o r s . N e v e r t h e l e s s , i t i s o b v io u s t h a t t h i s j j | | t e c h n iq u e i s e s s e n t i a l l y a c o n tin u o u s r e p r e c i p i t a t i o n ( o r j r e e r y s t a l i z a t i o n ) - l e a c h i n g o u t p r o c e s s r a t h e r t h a n a d s o rp 4 | t i o n - d e s o r p t i o n c h ro m a to g ra p h y . I I . C o n c lu s io n s D e riv e d From The L i t e r a t u r e R e s e a r c h and P ro p o s e d P l a n o f I n v e s t i g a t i o n The f o r g g o i n g l i t e r a t u r e r e s e a r c h l e a d s t o th e f o l lo w in g c o n c l u s i o n . F i r s t o f a l l , i t s h o u ld be p o i n t e d o u t t h a t no a tt e m p t h a s b e e n made t o a p p ly c h ro m a to g ra p h ic a d s o r p t i o n t o p o l y s t y r e n e . S eco n d , i t i s a v e r y r e m a r k a b le t h a t v e r y few p a p e r s d e a l i n g w i t h c h ro m a to g r a p h ic s tu d y o f | h i g h m o le c u la r s u b s ta n c e s o t h e r t h a n n a t u r a l l y o c c u r r i n g I p o ly m e rs h a v e b e e n p u b l i s h e d . I f one c o n s i d e r s t h a t a lm o s t I a l l o t h e r ty p e o f compounds h a v e b e e n t h o r o u g h ly i n v e s t i - i g a te d b y many d i f f e r e n t a u t h o r s , o n e m ight w e l l a s k why | so few s t u d i e s h a v e b e e n done o n t h e s u b j e c t o f c h ro m a to - | g r a p h i c a d s o r p t i o n o f h i g h p o ly m e rs . S e v e r a l r e a s o n s f o r ! I t h i s may be sum m arized a s f o l l o w s . I | I t i s g e n e r a l l y d i f f i c u l t t o o b s e r v e t h e s e c o l o r l e s s | s u b s ta n c e s on t h e colum n o r i n t h e e f f l u e n t s . Of c o u r s e a i ' ' l o t o f s u g g e s t i o n s h a v e b e e n made t o f a c i l i t a t e th e u s e o f I ; a d s o r p t i o n a n a l y s i s o f c o l o r l e s s s u b s t a n c e s . Among them , | W in s te in and Schoen'p4 ’ K a r r e r and S e h o e p p -^ h a v e s u g g e s te d i o b s e r v in g t h e colum n i n t h e u l t r a v i o l e t l i g h t b y t a k i n g i j I ; a d v a n ta g e o f t h e d i f f e r e n c e s i n t h e f l u o r e s c e n c e e x h i b i t e d by t h e z o n e s . B ro c k m a m r^ ” ^ h a s s u g g e s te d u s i n g W in s te in and S ch o en , Z .P h y s i o l . Chem. 230 139 (193*+) 15 P . K a r r e r and K. S ch o ep p , H e lv . Chim. A c ta 17 692 (193*+) 16 m. B rockm ann, Angew. Chem.~ A^9 199 Cl9^7) ^ ” > D i s c u s s . F a r a d . S o c . 2, 58 #19^9) l o and— F~.—Vol-p e r ^ -Ghem-.— B e r — §2— 95—^1- 9 1+9-)----- 19 « and E . B e y e r, Agnew. C hon. 63 133 (1 9 5 1 ) 1 $ f l u o r e s c e n t a d s o r b e n t s . A n o th e r p o s s i b i l i t y i s t o c o n v e r t a c o l o r l e s s s u b s ta n c e i n t o a c o lo r e d one by m eans o f a s u i t a b l e r e a c t i o n e i t h e r b e f o r e o r a f t e r a d s o r p t i o n . T here a r e a l s o c e r t a i n p o s s i b i l i t i e s o f t r e a t i n g t h e colum n w i t h i n d i c a t o r s w h ic h l o c a t e t h e ban d th r o u g h o u t t h e e n t i r e | e x p e r im e n ts a s i n t h e e a s e o f t h e a d s o r p t i o n a n a l y s i s o f o r g a n i c a c i d s and am ino a c i d s . H ow ever, t h e s e m ethods m e n tio n e d ab o v e c an n o t be a p p l i e d t o s y n t h e t i c h ig h p o ly m e r s . On t h e o t h e r h a n d , i t i s w e l l known t h a t a l l s y n t h e t i c j h i g h p o ly m e rs c o n s i s t o f m o le c u le s o f s i m i l a r s t r u c t u r e j b u t w ith m o le c u la r w e ig h ts c o v e r in g a f a i r l y b ro a d r a n g e j o f v a l u e s . They h a v e a c o n tin u o u s d i s t r i b u t i o n o f m o lecu l a r w e ig h t and no d i s c r e t e zone w i l l be e x p e c te d . I t i s t h e r e f o r e n o t p r o f i t a b l e t o s tu d y a l i m i t e d num ber o f j ! j f r a c t i o n s i n th e e f f l u e n t . F u r th e r m o r e , due t o t h e c o n tin u - i w i o u s d i s t r i b u t i o n o f m a t e r i a l on th e colum n, i t i s a l s o n e c e s s a r y t o h a v e a v e r y w e l l p a ek e d colum n b e c a u s e a n u n e v e n f r o n t w i l l c a u s e g r e a t e r r o r s i n t h e o b s e rv e d d i s t r i b u t i o n o f m a t e r i a l . A d d i t i o n a l d i f f i c u l t y i s e n c o u n te r e d due t o t h e f a c t t h a t t h e am ounts o f p o ly m e r a d s o rb e d a r e i n g e n e r a l , low and t h e r a t e o f a d s o r p t i o n i s a l s o v e r y s lo w .^ R e c o g n iz in g t h e s e d i f f i c u l t i e s i n c a r r y i n g o u t t h e s tu d y o f c h ro m a to g ra p h y o f h ig h p o ly m e rs , t h e f o l lo w in g a p p ro a c h i s p ro p o s e d f o r i n v e s t i g a t i o n . I t i s w o r th n o t i n g t h a t no w o rk h a s b e e n don e on th e s tu d y o f c h r o m a to g r a p h ic a d s o r p t i o n o f p o l y s t y r e n e . I n t h i s s t u d y t h e p o l y s t y r e n e f r a c t i o n s o f known m o le c u la r w e ig h ts w i l l be u s e d . A c t i v a t e d c h a r c o a l and c e l i t e w i l l be u se d a s a d s o r b e n t and t h r e e s o l v e n t s , m e th y l e t h y l k e to n e , p o o r s o l v e n t , t o l u e n e , b e t t e r s o l v e n t , and t e t r a l i n , b e s t s o l v e n t , w i l l be u s e d s e p a r a t e l y f o r t h e e l u t i o n t o i n v e s t i g a t e t h e s o l v e n t e f f e c t s . L a t e r t h e s e t h r e e s o l v e n t s w i l l be com bined t o e l u t e s t e p w i s e l y t h e p o l y s t y r e n e d e p o sij- | t e d on t h e colum n. F i n a l l y , t h e e l u t i o n w i l l be c a r r i e d o u t ! w i t h m ixed s o l v e n t s t o i n v e s t i g a t e t h e e f f e c t i v e n e s s o f t h e i s e p a r a t i o n o f p o l y s t y r e n e . The r e a s o n f o r t h i s c h o ic e i s ! i i i t h a t s t u d i e s on t h e a d s o r p t i o n b e h a v io r o f p o l y s t y r e n e o n tc c a rb o n h a v e b e e n done t o some e x t e n t . T h i s , we s h a l l s e e , j > ' ' | w i l l l e a d t o a b e t t e r u n d e r s t a n d i n g o f th e o b s e r v a t i o n s . | The a n a l y s i s o f f r a c t i o n s w i l l be c a r r i e d o u t by means o f \ | v i s c o m e t r y . The e s s e n t i a l a d v a n ta g e s o f v i s c o m e tr y a r e t h a t i t i s s im p le t o p e r f o r m , and r e l a t i v e l y r e l i a b l e d a t a a r e o b t a i n a b l e , fro m w h ic h t h e v i s c o s i t y a v e r a g e m o le c u la r w e ig h t o f th e p o l y s t y r e n e i n t h e f r a c t i o n c a n b e o b t a i n e d . On th e o t h e r h a n d , i n view o f t h e f a c t t h a t th e 1 j i a p p l i c a t i o n o f t h e p a r t i t i o n colum n c h ro m a to g ra p h y to t h e j I ! ; 1 s e p a r a t i o n o f n a t u r a l l y o c c u r r i n g p o ly m e rs h a s b e en shown J I v e r y s u c c e s s f u l , an a tt e m p t w i l l a l s o b e made t o i n v e s t i - | i ! I g a t e th e p o s s i b i l i t y o f a p p ly in g t h i s t e c h n i q u e t o t h e i ; i i ■ i s e p a r a t i o n o f s y n t h e t i c h i g h p o ly m e r, p o l y s t y r e n e . CHAPTER I I I CHROMATOGRAPHIC ADSORPTION OF POLYSTYRENE I . A n a ly s is o f F r a c t i o n s S in c e t h e f i n a l i n t e r e s t i n t h i s s tu d y i s t o s e e w h e th e r t h e f r a c t i o n a t i o n o f p o l y s t y r e n e o c c u r s o r n o t , a te c h n iq u e f o r t h e d e t e c t i o n o f t h e m o le c u la r w e ig h t o f f r a c t i o n s h a s t o be e s t a b l i s h e d . The s i m p l e s t r e l i a b l e way i s t h e d e t e r m i n a t i o n o f t h e v i s c o s i t y a v e r a g e m o le c u la r w e ig h t o f t h e p o l y s t y r e n e p r e s e n t i n t h e f r a c t i o n . I t h a s b e e n o b s e r v e d t h a t t h e e m p i r i c a l r e l a t i o n = K M a (1 ) h o l d s f o r f a i r l y l a r g e ra n g e o f m o le c u la r w e ig h t o f t h e | l i n e a r p o ly m e rs , M. H e r & £ $ $ i s th e i n t r i n s i c v i s c o s i t y , i S K and a a r e c o n s t a n t s f o r a g iv e n p o ly m e r - s o lv e n t p a i r a t i a g iv e n t e m p e r a t u r e . F o r s u f f i c i e n t l y d i l u t e s o l u t i o n s i t I | may b e assum ed t h a t c v j t z s ( ? s p / c ) c (2 ) w h e re ^)Sp i s s p e c i f i c v i s c o s i t y o f a p o ly m er s o l u t i o n h a v in g t h e c o n c e n t r a t i o n , C i n gram s o f p o ly m er p e r 100 ml, i ' s o l u t i o n . I f th e c o n c e n t r a t i o n o f th e polym er o f e a c h f r a c t i o n c a n be o b t a i n e d b y some m eans t h e n o n ly th e S m easu rem en t o f th e ^sp w i l l g iv e t h e a v e ra g e m o le c u la r | w e ig h t o f t h e p o ly m er p r e s e n t i n th e f r a c t i o n p r o v id e d | t h a t K and a h a v e b e e n e s t a b l i s h e d f o r a g i^ e n po ly m er j i n a g iv e n s o l v e n t a t a s p e c i f i e d t e m p e r a t u r e . I n c i d e n t a l l y , t h e m o le c u la r w e ig h t c a l c u l a t e d by E q. (1 ) i s th e v i s c o s i t y a v e ra g e m o le c u la r w e ig h t (M^.) w h ich i s r e l a t e d t o w e ig h t 9 0 a v e r a g e m o le c u la r w e ig h t b y ^ w ^ f t v = I 2 wt M i< " 1 (3) Where UOi and Mi a r e w e ig h t f r a c t i o n and w e ig h t a v e ra g e m o le c u la r w e ig h t o f s p e c i e s i , r e s p e c t i v e l y , a t h e same c o n s t a n t w h ic h a p p e a re d i n E q. C l) . S e v e r a l ways o f m e a s u rin g t h e c o n c e n t r a t i o n o f p o ly m e rs h a v e b e e n p r o p o s e d . Nam ely, (1 ) d i r e c t w e ig h in g o f p o ly m e rs l e f t a f t e r th e e v a p o r a t i o n o f t h e s o l v e n t.^ * (2 ) d i r e c t w e ig h in g o f p o ly m e rs w h ic h a r e p r e c i p i t a t e d w i t h a l a r g e am ount o f p r e c i p i t a n t (M e th an o l i n t h e c a s e o f p o l y s t y r e n e ) f o llo w e d by d e c a n t a t i o n and d r y in g p r o c e s s . 13>22 (3 ) M e a su rin g th e r e f r a c t i v e in d e x o f t h e poly m er s o l u t i o n w i t h a m i c r o - i n t e r f e r o m e t e r .7 >23 (H-) m e a s u rin g t h e t u r b i l i t y p ro d u c e d by a d d i t i o n o f p r e c i p i t a n t w i t h a n e p h e l o m e t e r .2 ^ 20 p. F l o r y , P r i n c i p l e s o f P olym er C h e m is try . C o r n e l l U n i v e r s i t y P r e s s , p . 3 1 3 , 1953 21 j . Hobden and H. J e l l i n e k , J . P o ly m er S c io I I 365 (19 53) 22 h . J e l l i h e k and H. N o rth e y , I b i d . ] h 583 (1 9 5 ^ ) 23 A. T i s e l i u s and S . C la e s s o n , A r k i v . Kem i. M in. G e o l. B15 No. 18 (1 9 ^ 2 ) 2¥ e . J e n e k e l and B. Rumbach, Z . E le c tr o c h e m . 55 -6l-2“-(195"l“)-------------------------------------------------------------------------------------------- __________________________ . _ 19 | (5 ) m e a s u rin g t h e v i s c o s i t y a v e ra g e m o le c u la r w e ig h t o f p o ly m er s o l u t i o n s o f unknown c o n c e n t r a t i o n by u s i n g two m i s c i b l e s o l v e n t s . 25 A n o th e r p o s s i b l e way o f m e a su rin g t h e c o n c e n t r a t i o n o f p o ly m er i n th e f r a c t i o n c a n be a c h ie v e d by u s i n g a B .S . d i f f e r e n t i a l r e f r a c t o m e t e r 26 by w h ic h a d i f f e r e n c e i n r e f r a c t i v e in d e x b e tw e e n a d i l u t e s o l u t i o n and i t s s o l v e n t c an be m ea su re d d i r e c t l y . The i n s t r u m e n t w as o r i g i n a l l y d e s ig n e d f o r o b t a i n i n g th e a d d i t i o n a l o p t i c a l d a t a r e q u ir e c . I f o r d e t e r m i n a t i o n o f th e m o le c u la r w e ig h t by t h e l i g h t j I I s c a t t e r i n g m eth o d . H ow ever, i t a l s o c a n b e u s e d f o r t h e i | d e t e r m i n a t i o n o f t h e c o n c e n t r a t i o n o f a d i l u t e s o l u t i o n . | The e s s e n t i a l a d v a n ta g e s o f t h i s m ethod a r e : j i ! 1 . I t i s s im p le t o o p e r a t e , and o n ly 1 m l. o f t e s t j l i q u i d i s r e q u i r e d . ! i I 2 . The l i m i t i n g s e n s i t i v i t y i s b e t t e r t h a n 3 u n i t s j i n th e s i x t h d e c im a l p l a c e . : i I 3 . S in c e th e d i f f e r e n c e i n t h e r e f r a c t i v e i n d e x i ! b e tw e e n s o l u t i o n and s o l v e n t i s m ea su re d by t h i s i n s t r u m e n t , on e c a n c o r r e c t th e p o s s i b l e e r r o r w h ic h m ig h t be e x p e c te d i n t h e e f f l u e n t due t o I i I t h e i m p u r i t y o f a d s o r b e n t by u s i n g th e w a sh in g ; a s a r e f e r e n c e i n s t e a d o f t h e p u r e s o l v e n t . i i I ______ _____________ j 25 h . F r i s c h and S . Yeh, J . P olvm er S c i . 20 *+31 ( 1 9 5 6 ). I , . . — ! 26 b . B r i c e and R. S p e i s e r , J . O p t. S o c . Am. 36 363 ( 1 9 ^ 6 ) . From t h i s p o i n t o f v ie w , t h i s m ethod i s b e s t f o r th e d e t e r m i n a t i o n o f p o ly m er c o n c e n t r a t i o n o f e a c h f r a c t i o n , w h ere a s i n g l e s o l v e n t i s u s e d f o r e l u t i o n . H ow ever, t h i s m ethod i s n o t a p p l i c a b l e when a m ix tu r e o f s o l v e n t s i s u se e f o r e l u t i o n . M ethod (1 ) i s s u i t a b l e f o r t h i s c a s e when a r e l a t i v e l y v o l a t i l e s o l v e n t i s u s e d and m ethod (2 ) f o r a r e l a t i v e l y h i g h e r b o i l i n g s o l v e n t . I I . E x p e r im e n ta l M a t e r i a l s . i ■ ' - ■ ■ ■ 1 ■ ■ ■ i | (A) P o l y s t y r e n e . * ( f r a c t i o n s ) | L i s t e d below a r e th e p o l y m e r i s a t i o n te m p e ra - I i \ t u r e s and t h e a v e r a g e m o le c u la r w e ig h ts o f p o l y s t y r e n e j f r a c t i o n s u s e d i n t h i s s t u d y . M o le c u la r w e ig h ts w ere d e te r m in e d by l i g h t s c a t t e r i n g ! F r a c t i o n No. M. W. POLYMERISATION TEMPERATURE No. 1 6 0 ,0 0 0 1 8 0 ° C No. 2 6 7 0 ,0 0 0 6 0 ° C j No. 3 1 ,5 0 0 ,0 0 0 3 0 ° G | | (B) A d s o r b e n ts . j I i C arbons A c t i v a t e d c h a r c o a l made by Merk & Co.I was d r i e d a t 1 1 0 ° C. f o r U -8 h o u r s and ! s t o r e d o v e r PifC^Q i n a d e s i c c a t o r . I * P o l y s t y r e n e f r a c t i o n s u s e d i n t h i s s tu d y w ere s u p p lie d ; I b y Dow C h em ical Company. D ata on t h e s e was o b t a i n e d froni D r. R. B. D ahl o f t h e P l a s t i c B a s ic R e s e a r c h L a b o r a to r y j o f t h e Dow C hem ical Company, M id la n d , M ich . j C e l i t e : A n a l y t i c a l g r a d e o f J o h n s - M a n v ille Col p r o d u c t was t r e a t e d i n t h e same way a^ t h e c a r b o n . f A l a r g e amount ©f a m ix tu r e o f t h e c a rb o n and j c e l i t e (1 p a r t c a rb o n and 3 p a r t s c e l i t e b y w e i g h t ) , a s recom m ended by C la e s s o n , was made by g r i n d i n g th e p r e - d r i e d a d s o r b e n t s i n a m o rta r t o make i t hom ogeneou s. A f t e r m i x i n g 't h e m ix tu r e w as k e p t o v e r the-P^O ^Q i n a d e s i c c a t o r , , t h i s m ix tu r e was u s e d t h r o u g h o u t t h i s s t u d y . (C) S o l v e n t s . j T o lu e n e : B aker & Adamson p r o d u c t s . (G e n e ra l i i | C h e m ica l D i v i s i o n , A l l i e d Chem. & i i I Dye C o .) A .C .S . R e a g e n t g ra d e d r i e d i w i t h m e t a l l i c so d iu m . M e th y l e t h y l k e to n e : M ath eso n Colem an & B e l l Co. D rie d w i t h c a lc iu m c h l o r i d e a n h y d r id e . i i j T e t r a l i n : E astm an o r g a n i c c h e m ic a ls p r o d u c t , i I " ' | i p r a c t i c a l g r a d e ; d r i e d w ith m e t a l l i c i I sodium . | M eth y l A lc o h o l: B a k er & Adamson P r o d u c t (Geneij- > i I a l C h e m ica l D i v i s i o n . A l l i e d I j C h em ical & Dye C o .) . A .C .S . I | | r e a g e n t g ra d e ( a b s o l u t e ) . ? I | A l l s o l v e n t s , e x c e p t a b s o l u t e m e th a n o l, w e re d i s t i l l e d a f t e r d r y i n g , and th e c o n s t a n t b o i l i n g p o r t i o n was c o l l e c t e d f o r u s e . T h e_ b c d L lin g _ p o in ts_ a n d — r-e.fr.ac.tive----------- 2 2 i n d i c e s o f t h e s o l v e n t s a r e shown b e lo w : i B. P . % 2b°C T o lu e n e 1 1 0 .5°C 1 .^ 9 5 1 M eth y l E th y l K e to n e 7 9 .7 °C 1 .3 7 8 2 T e t r a l i n 207 .9°C 1 .5 ^ 0 2 P r o c e d u r e . The g e n e r a l c h ro m a to g ra p h ic p r o c e d u r e c a n be d i v i d e d i n t o t h r e e s t e p s , n a m e ly , ( a ) p a c k in g o f t h e colum n, (b ) a p p ly in g t h e sa m p le t o t h e colum n and (e ) i i e l u t i o n and t h e c o l l e c t i o n o f f r a c t i o n s . i j j A l l colum ns w ere p a c k e d by a "w et m e th o d ": A known! ! w e ig h t o f a d s o r b e n t was p l a c e d i n t h e b e a k e r , and a s l u r r y i ! was made i n su c h a way t h a t i t h a d s u i t a b l e f l u i d i t y t o flo w by a d d in g a s m a ll am ount o f s o l v e n t t o be u se d f o r t h e e l u t i o n . W hile t h e s l u r r y was p o u r in g i n t o a colum n w hose b o tto m i s s u p p o r te d b y g l a s s w o o l, t h e s o l v e n t i s a llo w e d I ^ • \ \ t o r u n th r o u g h t h e colum n . A t y p i c a l s m a ll column" was | made a s f o l l o w s . A s l u r r y was made w i t h 1 0 .0 g r . o f a d - | I * | ; j s o r b e n t , a m ix tu r e o f c a rb o n and c e l i t e , and a b o u t 60 m l. ! o f s o l v e n t . Then t h e s l u r r y was p o u re d i n t o 50 m l. b u r e t ( i n t e r n a l d ia m e te r 1 .1 cm .) i n w h ic h was p la c e d 0 .2 5 g r . j i \ o f g l a s s w ool f o r s u p p o r t . The a d s o r b e n t r e m a in in g i n the! ; t I b e a k e r w as w ashed i n t o t h e colum n b y a d d i t i o n a l s o l v e n t , i ! j i I i The colum n was t h e n w ashed w i t h t h e s o l v e n t f o r 12 h r s . j I ; ! I I c o n t i n u o u s l y . T h is a l s o a llo w s t h e colum n to s e t t l e down ! ! - 1 ! t o an a p p ro x im a te h e i g h t o f 55 cm. A n o th e r t y p e o f column! i ( i n t e r n a l d ia m e te r 2 .3 cm) was made w ith 3 2 g r . o f c a rb o n and c e l i t e m ix tu r e i n a p y r e x tu b e a t w hose b o tto m i s p l a c e d 1 g r . o f g l a s s w ool on w h ic h a s m a ll p o r c e l a i n d i s c p e r f o r a t e d w i t h a h o l e o f a p p r o x im a te ly 1 mm. r e s t s . T r e a t i n g i n a s i m i l a r m anner t h i s colum n g i v e s a n a d s o r p t i o n colum n o f a b o u t 30 cm. o f h e i g h t . T h is p a c k in g t e c h n iq u e h a s t h e a d v a n ta g e o f a v o id in g t h e p r e s e n c e o f a i r b u b b le s i n t h e colum n, w h ich t e n d s t o c a u se n o n - u n ifo rm p a c k in g and i r r e g u l a r flo w o f s o l v e n t . A f t e r w a sh in g o f t h e colum n t h e s o l v e n t r e m a in in g o n t h e to p o f th e colum n w as w ith d ra w n by s y r i n g e t o l e a v e o n ly a v e r y s m a ll am ount; j u s t enough t o k e e p t h e t o p o f t h e colum n w e t. S in c e t h e to p o f t h e a d s o r b e n t m ust be f l a t and s h o u ld n o t be d i s t u r b e d when th e t e s t l i q u i d i s I a p p l i e d , t h e p o ly m er s o l u t i o n t o b e f r a c t i o n a t e d , 0 . 5% I (w t./lO O ml s o l u t i o n ) , was a p p l i e d by p i p e t whose t i p was I | made t o t o u c h t h e i n n e r w a l l o f t h e colum n, a s n e a r th e t j i t o p o f t h e colum n a s c a n be m anaged w i t h o u t to u c h in g t h e i s u r f a c e o f t h e a b s o r b e n t . The colum n was t h e n a llo w e d t o | r u n u n t i l t h e s u r f a c e o f t h e l i q u i d w as b ro k e n by t h e p r o t r u d i n g p a r t i c l e s o f t h e a d s o r b e n t . A f t e r t h i s a s m a ll q u a n t i t y o f s o l v e n t was a p p l i e d s e p a r a t e l y , i n a s i m i l a r I ; i ' ’ j m an n e r, t o rem ove a l l t r a c e o f t h e t e s t sam ple and c a r r y tike i I l a s t down t h e colum n. T h is colum n i s now r e a d y t o b e e l u t e d . The g e n e r a l schem e o f th e e l u t i o n p r o c e d u r e i s whown j | i n F i g . 1 . I t h a s b e e n o b s e r v e d t h a t t h e r a t e o f a d s o r p - i t i o n f o r h i g h p o ly m e rs i s , i n g e n e r a l , v e r y s l o w .0 T h e r e f o r e , 2.4 i n o r d e r t o r e a e h a d s o r p t i o n e q u i l i b r i u m t h e r a t e o f f lo w th r o u g h t h e colum n, w h ic h i s a d j u s t a b l e by s t o p c o c k s a t t h e b o tto m o f colum n and s o l v e n t r e s e r v o i r ; o r th e h e i g h t o f s o l v e n t r e s e r v o i r , m ust be k e p t slo w ( 0 . 1 ~ G .2 m l./m in .) j. • I [ I n c o n j u n c t i o n w i t h t h e low r a t e o f f l o w , c a r e was ta k e n I t o a v o id th e e v a p o r a t i o n o f t h e s o l v e n t fro m t h e f r a c t i o n and t o p r e v e n t t h e c o n ta m in a tio n by w a t e r v a p o r o f th e f r a c t i o n . Such c o n ta m i n a ti o n w ould a f f e c t th e r e f r a c t i v e in d e x o f t h e s o l u t i o n . The p r e s s u r e ab o v e t h e colum n was j t ! r ! j m a in ta in e d a s shown i n F i g . 1 by u s e o f r e s e r v i o r . T h is j | m a i n t a i n s a c o n s t a n t l e v e l o f t h e s o l v e n t i n t h e colum n i | i t s e l f w h ile t h e p r e s s u r e v a r i e d s l i g h t l y a s t h e l e v e l l r I i n t h e l a r g e r e s e r v o i r b u lb c h an g ed w i t h t i m e . i \ The f r a c t i o n s , 10 m l. e a c h , w e re c o l l e c t e d i n a g r a d u a te d c e n t r i f u g e tu b e o n a volum e b a s i s . The room ! t e m p e r a t u r e was r e c o r d e d by a n a u to m a tic r e c o r d e r I n a l l | c a s e s , t h e room t e m p e r a t u r e c h a n g e s d u r in g t h e r u n do n o t } e x c e e d ^ d e g r e e s , ( i . e , T = » 2j> ± 2°C ) j i J D e t e r m in a t io n o f P o ly m er C o n c e n t r a t i o n i n t h e ! C h ro m a to g ra p h ic F r a c t i o n s . As p o i n t e d o u t b e f o r e , t h e 1 ! | p o ly m er c o n c e n t r a t i o n i n e a c h f r a c t i o n c a n be m ea su re d by ! ! ! | a B .S . d i f f e r e n t i a l r e f r a c t o m e t e r when a s i n g l e s o l v e n t i was u s e d f o r t h e e l u t i o n . The i n s t r u m e n t c o n s i s t s o f a j I m e rc u ry lam p , m o n o ch ro m atic f i l t e r s ( g r e e n f i l t e r , "X - « 5^60 2 ) , p r o j e c t o r l e n s and t h e d i f f e r e n t i a l c e l l . The i ■ | l a t t e r i s p r o b a b ly t h e m ost i m p o r t a n t and d e l i c a t e o f t h e M g . 1 DIAGRAM OF THE ABSORPTION COLUMN w h o le a s s e m b ly . I t i s an o p t i c a l s i n t e r - f u s e d c e l l w i t h two c o m p a rtm e n ts and i s m ounted by m eans o f s e t sc re w s j b e a r i n g a g a i n s t p l a s t i c s h e e t s o n a r o t a t a b l e h o l d e r i n a j | j a c k e t e d h o u s i n g . R o t a t i o n o f th e c e l l th r o u g h l 8 0 ° i s t | I a c c o m p lis h e d by m eans o f a h a n d le w i t h a d j u s t a b l e s t o p s . s The e y e - p i e e e s c a l e was d i v i d e d i n t o t e n e q u a l d i v i s i o n s w h ile t h e m ic ro m e te r drum was d i v i d e d i n t o a h u n d re d d i v i s i o n s . The s o l u t i o n s a r e added w i t h a p i p e t t e and | rem oved fro m c e l l w i t h a v e r y f i n e ty g o n t u b e by w a te r I ! | pump s u c t i o n . The c e l l i s c le a n e d w i t h t h e s o l v e n t s e v e r a l j tim e s b e f o r e e a c h m e a su re m e n t. Tap w a t e r i s c i r c u l a t e d i n j ! t h e j a c k e t s u r r o u n d in g t h e h o u s in g o f t h e c e l l . Of c o u rse ,j l i j h e r e , we a r e i n t e r e s t e d i n t h e d i f f e r e n c e o f r e f r a c t i v e i ’ \ j in d e x b e tw e e n two l i q u i d s and n o t i n t h e a b s o l u t e v a l u e ! i i o f t h e r e f r a c t i v e in d e x o f any l i q u i d , and h e n c e t h i s j i i | te m p e r a t u r e c o n t r o l n e e d n o t b e v e r y r i g o r o u s . A s l i g h t ! v a r i a t i o n i n t e m p e r a t u r e w i l l h a v e t h e same e f f e c t o n t h e i | I r e f r a c t i v e i n d i c e s o f t h e s o l v e n t and t h e d i l u t e s o l u t i o n I ; ' i : and t h e d i f f e r e n c e w i l l be t h e same p r o v id e d s o l u t i o n and j i ' I ; i i s o l v e n t a r e k e p t a t t h e same t e m p e r a t u r e . I n c i d e n t a l l y , I | ! I t h e t e m p e r a t u r e o f th e t a p w a te r was c h e c k e d e v e r y t i m e . j ' I t a lw a y s s c a t t e r e d w i t h i n 2*+.5 £ 0 . 5 °C • j : i | To s t a r t w i t h , 1 m l. o f s o l v e n t was k e p t i n e a c h ) ; co m p artm en t o f t h e c e l l . The m ic r o s c o p e w as f o c u s s e d on j • t h e s l i t im age and th e v e r n i e r drum w as r o t a t e d so a s t o I I b r i n g t h e c r o s s h a i r e x a c t l y on t h e im a g e . The p o s i t i o n I f„of„the_drum_w.as„noJLed.. LeJb_i_t_be_._c_alleii_d.2_. When., t h e I c e l l was t u r n e d th r o u g h l 80° , t h e m ic ro s c o p e a g a i n f o c u s s e d , i f n e c e s s a r y , and t h e c r o s s h a i r a d j u s t e d t o b e e x a c t l y on t h e im age a g a i n and t h e r e a d i n g t a k e n , 6.2* T h is p r o c e d u r e was r e p e a t e d s e v e r a l tim e s t o o b t a i n d^ and a l t e r n a t i v e l y by r o t a t i n g t h e c e l l t h r o u g h l 8o ° . The a v e r a g e v a l u e o f d j - d 2 i s c a l l e d 1 1 z e r o - c o r r e c t i o n " . A f t e r t h e z e r o - c o r r e c t i o n was d e te r m in e d , t h e s o l v e n t fro m one o f t h e c o m p a rtm e n ts was r e p l a c e d w i t h t h e s o l u t i o n and a llo w in g 5 -1 0 m in u te s f o r t e m p e r a t u r e e q u i l i b r i u m , d^ and I d 2 w ere d e te r m in e d i n a s i m i l a r m an n e r. The a v e r a g e v a l u e | I ' ! j o f d]_-d2 f o r t h e s o l u t i o n m inus t h e z e r o c o r r e c t i o n g i v e s [ t h e c o r r e c t e d v a lu e o f a d f o r t h e s o l u t i o n . The d i f f e r - i i ! e n ce i n r e f r a c t i v e in d e x b e tw e e n a s o l u t i o n and t h e s o l v e n t c a n be c a l c u l a t e d fro m t h e f o r m u la ^ n - K Ad (k) i I j w h ere a n i s th e d i f f e r e n c e i n r e f r a c t i v e in d e x and i d i s j 1 t h e q u a n t i t y d e f i n e d a b o v e , and K i s c a l l e d th e i n s t r u - i 1 m ent c o n s t a n t . I i j F o r t h e d e t e r m i n a t i o n o f c o n c e n t r a t i o n s , k n o w led g e i o f t h e d i f f e r e n c e i n r e f r a c t i v e in d e x b e tw e e n th e s o l u t i o n and t h e s o l v e n t i s r e a l l y u n n e c e s s a r y . I f a g r a p h o f A d v s . i i I c o n c e n t r a t i o n i s p l o t t e d , t h e n t h e c o n c e n t r a t i o n o f th e j unknown s o l u t i o n c an be c a l c u l a t e d from t h e g r a p h know ing t h e v a lu e o f Ad f o r t h a t s o l u t i o n . T hus t h e v a l u e o f t h e I | i n s t r u m e n t c o n s t a n t , K i s n e c e s s a r y o n ly when we a r e I i n t e r e s t e d i n know ing A n and n o t o t h e r w i s e . I i H ence t o e s t i m a t e t h e c o n c e n t r a t i o n o f an unknown p o l y s t y r e n e s o l u t i o n , a c a l i b r a t i o n was c a r r i e d o u t . N am ely, s o l u t i o n s o f d i f f e r e n t c o n c e n t r a t i o n s w ere p r e p a r e ^ and t h e v a l u e s o f d w e re d e te r m in e d . Thus a g ra p h o f Ad ! i i v s . c o n c e n t r a t i o n w as c o n s t r u c t e d . By know ing Ad f o r an y unknown s o l u t i o n i t s c o n c e n t r a t i o n c a n be fo u n d by i n t e r p o l a t i o n . The c a l i b r a t i o n f o r p o l y s t y r e n e i n b e n z e n e , p o l y s t y r e n e i n t e t r a l i n a r e shown b e lo w . P o l y s t y r e n e S o lv e n t f r a c t i o n s Ad » K'C . . T o lu e n e 1 .5 x 1 0 6 a d - = 1.33 2C 6*0 x 10* * a d 4 i.3*f9C T e t r a l i n 1 . 5 x 106 a d = 0 . 6 3 8c 6 .0 x . 0* * a d - 0.6M fC The r e l a t i o n a d 55 k 'G (5 ) w as o b s e r v e d w i t h i n th e c o n c e n t r a t i o n r a n g e we a r e i n t e r - e s t e d i n ( 0 . 1- 0 . 3$ ) . H ere K 1 i s a c o n s t a n t and C i s a i i j c o n c e n t r a t i o n i n gram p e r 100 m l. s o l u t i o n . F u r th e r m o r e , | • i ! t h e c o n s t a n t , K ’ , i n E q. (5 ) i s d e p e n d e n t on t h e s o l v e n t ! i ! v e r y much, b u t v e r y s l i g h t l y on t h e m o le c u la r w e ig h t o f j I | t h e p o l y s t y r e n e . The p r e c i s i o n i n m e a s u rin g t h e v a l u e s ; o f a d i s — 0 .3 d i v i s i o n s on t h e m ic ro m e te r drum and h e n c e j j th e c o n c e n t r a t i o n e s t i m a t i o n i s good up t o t h e 3r d d e c im a l ! p l a c e . I n p r a c t i c e , f o r th e m e a su re m e n ts o f poly m er e o n - i ' j | c e n t r a t i o n o f e a c h f r a c t i o n t h e colum n w a sh in g s o l v e n t j j I w as u s e d a s a r e f e r e n c e i n s t e a d o f p u r e s o l v e n t . S in c e t h e m ethod d e s c r i b e d a b o v e i s n o t a p p l i c a b l e t o m ix t u r e s o r s o l v e n t s , th e am ount o f p o ly m e r p r e s e n t i n t h e f r a c t i o n s w h ic h w e re e l u t e d w ith t h e m ix tu r e o f s o l v e n t s was o b t a i n e d a s f o l l o w s : I f t h e s o l v e n t i s r e l a t i v e l y v o l a t i l e , e . g . MEK o r t o l u e n e , t h e f r a c t i o n s w e re t r a n s f e r r e d i n t o s m a ll p r e -w e ig h e d e rle n m y e r f l a s k s , and t h e s o l v e n t was d i s t i l l e d o f f u n d e r vacuum . A f t e r a l l s o l v e n t h a s e v a p o r a t e d , t h e p o ly m e rs w ere d r i e d a t 50°C u n d e r s u c t i o n by w a te r pump u n t i l c o n s t a n t w e ig h t was o b t a i n e d . The c o n c e n t r a t i o n o f p o ly m e r was t h e n c a l c u l a t e d . When s o l v e n t s w ith h i g h b o i l i n g p o i n t s w ere u s e d , i . e . , t e t r a l i n , t h e f r a c t i o n s w e re t r a n s f e r r e d i n t o a 1G0 m l. b e a k e r , and 60 m l. o f m e th a n o l was added t o p r e c i p i t a t e t h e p o l y s t y r e n e . A f t e r a c e r t a i n tim e , th e p o l y s t y r e n e s e t t l e d down a t t h e b o tto m o f t h e b e a k e r , was d e c a n te c l and w ashed w i t h a s m a ll am ount o f m e th a n o l ( a t l e a s t s i x v. t im e s ) and t r a n s f e r r e d i n t o t h e p re w e ig h e d e rle n m y e r f l a s k and t r e a t e d i n a s i m i l a r m anner a s d e s c r i b e d a b o v e . The I i a d v a n ta g e o f t h i s p r o c e d u r e i s t h a t t h e d e s i r e d c o n c e n tr a - j t i o n o f t h e po ly m er s o l u t i o n c a n be o b t a i n e d f o r a v i s c o s - | i t y m e a su re m e n t. V i s c o s i t y M e a su re m e n ts. The v i s c o s i t y o f e a c h f r a c t i o n was m easu red a t 25 ~ 0 .1 °C w i t h an O stw ald ty p e v i s c o m e te r w h ich h a s a flo w tim e o f a b o u t 700 se c o n d s f o r t o l u e n e . The s o l u t i o n was f i l t e r e d t h r o u g h a medium s i n t e r g l a s s f i l t e r b e f o r e p i p e t t i n g i n t o t h e v i s c o m e t e r . The f lo w tim e was m e a su re d w i t h a s t o p w a tc h t o 0 . 1 ’ se c o n d . I t was o b s e rv e d fro m th e i n t r i n s i c v i s c o s i t y m e a su re m e n ts o f p o l y s t y r e n e i n t o l u e n e t h a t , f o r f r a c t i o n s whose a v e r - . k 6 ag e m o le c u la r w e ig h t l i e s i n 6 x 10 - 1 x 10 r a n g e th e ( i ^ p / e ) v a l u e s a ro u n d 0 .1 $ do n o t d i f f e r v e r y much fro m o f t h a t f r a c t i o n . I n o r d e r t o j u s t i f y t h e a s s u m p t io n ,| E q . ( 2 ) , a l l v i s c o s i t y m e a su re m e n ts o f f r a c t i o n s w ere c a r r i e d o u t i n t o l u e n e and e a c h f r a c t i o n w as d i l u t e d i n su c h a way t o g iv e a c o n c e n t r a t i o n c l o s e t o 0 . 1 $ . A l l I i d i l u t i o n p r o c e d u r e s w e re c a r r i e d o u t by p i p e t t i n g . j i ! 1 * j I I I . R e s u l t s and D i s c u s s i o n I ! | A m ix tu r e o f p o l y s t y r e n e made o f e q u a l w e ig h ts o f i No. 1 f r a c t i o n (M.W. 6 x 10 ) and No. 3 f r a c t i o n (M.VJ. 1 . 5 x 106) was u s e d th r o u g h o u t t h i s s t u d y . The v i s c o s i t y | a v e r a g e m o le c u la r w e ig h t (M^) f o r t h i s m ix tu r e i n t o l u e n e ! was f o u n d , t h r o u g h E q. ( 3 ) , t o be 5*0 x 1 0 ^ . M o le c u la r I " i w e ig h ts o f th e p o l y s t y r e n e i n e a c h f r a c t i o n w ere e a l c u l a - ! t e d b y E q. (1 ) u s i n g E q. ( 2 ) . C o n s t a n ts , K and a i n E q. I i | (1 ) a r e 8.1*+ x 10” ^ and 0.75*tj r e s p e c t i v e l y ^ f o r t h e p o l y s t y r e n e - t o l u e n e s y s te m a t 25°C. i i E l u t i o n w i t h M e th v l E th v l K e to n e . , F o r c o m p a ris o n , ' ; [ j m e th y l e t h y l k e to n e , w h ic h i s a r e l a t i v e l y p o o r s o l v e n t s . j f o r p o l y s t y r e n e , was u s e d . f o r e l u t i o n . The colum n was | r im u n d e r t h e f o l l o w i n g c o n d i t i o n s : i a d s o r b e n t : c a r b o n c e l i t e m ix tu r e , l*f g r . ! i i colum n: I n t e r n a l d i a m e t e r 1 .1 cm .: h e i g h t *+8 cm. i ! _ • • i. sam p le a p p l i e d : 0 .1 5 9 g r . I t was o b s e r v e d t h a t e v e n a f t e r 11© m l. o f e f f l u e n t h a s b e e n c o l l e c t e d , no po ly m er was d e t e c t e d i n t h e f r a c t i o n s . A n o th e r r u n a l s o showed t h e same r e s u l t . T h is i n d i c a t e d t h a t p o l y s t y r e n e a d s o rb e d b y c a rb o n fro m t h e p o o r s o l v e n t s o l u t i o n c a n n o t be e l u t e d o u t w i t h t h e p o o r s o l v e n t i t s e l f . E l u t i o n w i t h T o lu e n e . T o lu e n e i s c o n s id e r e d t o be • 1 . i a b e t t e r s o l v e n t f o r p o l y s t y r e n e t h a n m e th y l e t h y l k e t o n e , j The colum n c o n d i t i o n s u s e d w e re : i | a d s o r b e n t : C arbon and c e l i t e m ix tu r e 10 g r . | colum n: I n t e r n a l d ia m e te r 1 . 2 cm .; h e i g h t 53 cm* | sam ple a p p l i e d : 0 .1 0 2 ^ g r . i I The p o l y s t y r e n e c o n c e n t r a t i o n o f e a c h f r a c t i o n was d e t e r - m ined by t h e B .S . d i f f e r e n t i a l r e f r a c t o m e t e r a s d e s c r i b e d I b e f o r e . The r e s u l t s o f a n a l y s i s o f f r a c t i o n s a r e shown i n j T a b le I I . F i g . 2 shows t h e d o u b le p l o t s o f m o le c u la r w e ig h ts c a l c u l a t e d by E q. (1 ) and t h e am ounts o f p o l y s t y r e n e fo u n d i n e a c h f r a c t i o n a g a i n s t t h e volum e o f e f f l u e n t , I t i s c l e a r from b o t h T a b le I I and F i g . 2 t h a t o n ly k | p o l y s t y r e n e h a v in g m o le c u la r w e ig h ts o f t h e o r d e r o f 10 i ! w e re e l u t e d o u t b y t h e t o l u e n e . F u r th e r m o r e , i t w as e l u t e d o u t i n t h e o r d e r o f i n c r e a s i n g m o le c u la r w e ig h t e x c e p t i | t h e l a s t f r a c t i o n w h ere th e e x p e r i m e n t a l e r r o r was enhanced. ! due t o th e f a c t t h a t th e p o ly m e r c o n c e n t r a t i o n was so s m a l l . ! k £ I The g r e a t e r p a r t o f t h e p o l y s t y r e n e i n c l u d i n g 10 and 10 i TABLE I I ANALYSIS OF FRACTIONS ELUTED- WITH TOLUENE ( LONG COLUMN) F r a c t i o n number m l. o f e f f l u e n t co n e , o f p o ly s ty r e n e Cone, a t w hich t}Sf> i s m eas. ^ SP/C K found Amount o f p o ly s ty r e n e i n t h e f r a c t i o n s # f , f i - 6 o 0.058 0.058 0 . 0 ^ 8 l.O x lO ^ 0 .5 8 x 1 0 " 2 g r 0 61-70 0 .1 1 ^ D . l l 1 * 0 .0 8 0 9 9 .^ x lo 3 l.lM- " m 71-80 0, lMf O.lMf 0.2 2 0 8 3 .6 x 1 0 ^ 1.M+ ” # a 81-90 0.0*fl O.O^l 0.1607 2 M l Q * o M « #9 91-100 0 .0 2 9 - - - 0 .2 9 M w fo o r d e r o f m o le c u la r -w eights re m a in e d on t h e colum n, and c o u ld n o t be e l u t e d o u t w i t h t o l u e n e ( 38$ r e c o v e r y ) . O th er r u n s showed t h a t th e r e s u l t s o b t a i n e d h e r e a r e r e p r o d u c i b l e .* I n o r d e r t o se e w h e th e r t h e r e s u l t s w e re due t o a d s o r p t i o n o r n o t , a S h o r t colum n w as made and r im u n d e r t h e f o l l o w i n g c o n d i t i o n s s a d s o r b e n ts c a rb o n and c e l i t e m ix tu r e 2g colum n h e i g h t s l 6 cms ( I n t e r n a l d ia m e te r 0 . 9 cm) sa m p le a p p l i e d s 0 .1 0 1 2 g T a b le I I I and F i g . 3 shows t h e r e s u l t s o f th e a n a l y s i s o f i | t h i s r u n . I t i s o b v io u s t h a t p r a c t i c a l l y no f r a c t i o n a t i o n j I was o b s e r v e d . T h is i n d i c a t e d t h a t i n o r d e r t o g e t a good j s e p a r a t i o n we m ust u s e a h i g h e r colum n and t h e r e s u l t s o b t a i n e d abo ve a r e due t o an a d s o r p t i o n - d e s o r p t i o n chrom a t o g r a p h i c p r o c e s s . E l u t i o n w ith T e t r a l i n . One o f t h e b e s t s o l v e n t s i f o r p o l y s t y r e n e i s t e t r a l i n w h ic h was u s e d h e r e t o i n v e s t i 4 t g a t e t h e b e h a v i o r o f a good s o l v e n t i n a d s o r p t i o n chrom a t o g r a p h y . The f o l l o w i n g colum n c o n d i t i o n s w e re u s e d ; | * By r e p r o d u c i b l e we mean i n s e v e r a l p a r a l l e l and ! c o n s e c u t i v e e x p e rim e n ts * e . g . The a n a l y s i s o f f r a c t i o n s j e l u t e d b y t o l u e n e ( c . f . T a b le I I ) i s r e p r o d u c i b l e i n c o n - ! c e n t r a t i o n t o b e t t e r t h a n 10$ and i n m o le c u la r w e ig h t t o 3 0 $ (maximum d e v i a t i o n i n two r u n s ) ; S i m i l a r l y th e a n a l y s i s o f f r a c t i o n s e l u t e d by t e t r a l i n ( c . f . T a b le 17) i s r e p r o d u c i b l e t o 18$ i n c o n c e n t r a t i o n and 20$ i n m o le c u la r | w e i g h t . (Maximum d e v i a t i o n i n two r u n s . ) TABLE I I I ANALYSIS OF FRACTIONS ELUTED WITH TOLUENE (SHORT COLUMN) F r a c t i o n n number ”m l. o f e f f l u e n t Cone, o f p o ly s ty r e n e Cone, a t w hich Vsp i s m eas. ■%*- V found Amount o f p o ly s ty r e n e i n th e f r a c t i o n s #1 0-10 0.020 0.020 1.252 3 . 6x10^ 0. 20x10”2 gr #2 11-20 0.^09 0.102 1. 65^ 5. 2x10^ > .0 9 " #3 21-30 0. 35^ 0.118 i ;>665 5. 2x10^ 3. > 31-^0 0.019 0.019 - ■ - 0.19 " #5 ^1-50 - m m - - Mv FOUND x 10 .3.5 6 5 4 Or 3 2 I 0 0 2 0 40 60 $0 100 UO 0 20 4 0 GO EFFLUENT IN ML. K g , » ■ J ig * ' 3 CHROMATOGRAM OF POLYSTYRENE OR CARBON-CELITE USING TOLUENE AS ELUENT. Eig. 2: REPRESENTS THE RESULTS OBTAINED BY USING A LONG COLUMN. Fig. 3 THOSE USING A SHORT COLUMN. .01 v iW V 3 6 a d s o r b e n t : c a rb o n c e l i t e 10 g colum n: I n t e r n a l d ia m e te r 1 .2 cm .; h e i g h t 50 cm. sam p le a p p l i e d : 0 .1 0 3 g The m ea su re m e n t o f p o ly m er c o n c e n t r a t i o n o f t h e f r a c t i o n s •was f i r s t t r i e d w i t h a B .S . d i f f e r e n t i a l r e f r a c t o m e t e r u s i n g t h e c a l i b r a t i o n shown b e f o r e . H ow ever, t h e poly m er c o n c e n t r a t i o n o f some f r a c t i o n s e x c e e d e d t h e r a n g e w h e r e in t h e c a l i b r a t i o n c h a r t i s v a l i d . I n o r d e r t o u n i f y th e e x p e r i m e n t a l c o n d i t i o n s , t h e p o ly m e r c o n c e n t r a t i o n s w ere | e s t i m a t e d by d i r e c t w e ig h in g (m ethod ( 2 ) ) . Nam ely, p o ly - j i s t y r e n e was p r e c i p i t a t e d w i t h MeOH a s d e s c r i b e d a b o v e , and! ! i ’ t h e v i s c o s i t y was m ea su re d by d i s s o l v i n g t h e r e c o v e r e d p o l y s t y r e n e i n t o l u e n e . To a s s u r e t h e c o r r e c t n e s s o f e x p e r i m e n t a l r e s u l t s t h e f o l l o w i n g p r e l i m i n a r y t e s t s w ere c a r r i e d o u t . 2 p o r - 1 ^ | t i o n s o f 1 0 .0 0 m l. o f t h e m ix tu r e s o l u t i o n , 0 .1 0 0 2 $ i n ■ — 5 i t e t r a l i n , o f w h ic h = 5*0 x 10^ w e re p i p e t t e d o u t i n t o tw o b e a k e r s , r e s p e c t i v e l y , and p o l y s t y r e n e was p r e e i p i t a - ! t e d w ith m e th a n o l. A f t e r d e c a n t a t i o n and w a sh in g w i t h j t h e m e th a n o l f o llo w e d by d r y i n g , th e p o l y s t y r e n e was w e ig h e d . T hen 1 0 .0 0 m l. o f t o l u e n e was added t o d i s s o l v e th e ! p o l y s t y r e n e and t h e v i s c o s i t y was m e a s u re d . The r e s u l t i s shown b e lo w : # Sam ple 1 2 P o l y s t y r e n e r e c o v e r e d m e a su re d M v fo u n d by m e th a n o l i n T o lu e n e 0 .0 9 8 5 g r 1 .8 1 0 5 .8 2 x 10^ 0 .0 9 9 0 g r 1.8l*f 5.8*+ x 10^ I t i s o b s e r v e d t h a t t h e r e c o v e r y o f p o l y s t y r e n e by m eans o f m e th a n o l i s r e a s o n a b l e and M v fo u n d a r e i n good a g r e e m ent w i t h My c a l c u l a t e d by E q. ( 3 ) . T h is a g a i n j u s t i f i e s t h e a s s u m p tio n o f E q. (2 ) a s w e l l a s j u s t i f y i n g t h e m ethod p ro p o s e d f o r t h e d e te r m i n a t i o n o f p o ly m e r c o n c e n t r a t i o n i n t h e f r a c t i o n s . The r e s u l t s o f t h e a n a l y s i s on t h e f r a c t i o n s c o l l e c t e d by u s i n g t e t r a l i n a r e shown i n T a b le IV and F i g . I t w as o b s e r v e d t h a t t h e p o ly m e rs o f M.W. o f t h e i | o r d e r o f 1CP w e re e l u t e d o u t , and th e r e c o v e r y o f t h e | p o ly m e r was much i n c r e a s e d (9 0 .5 $ )« F u r th e r m o r e , i t i s i v e r y i n t e r e s t i n g t o n o t e t h a t t h e y a r e e l u t e d i n t h e o r d e r o f i n c r e a s i n g m o le c u la r w e ig h t e x c e p t t h e f i r s t tw o f r a c t i o n s , w h ic h i s p r o b a b ly due t o t h e e x c e s s c h a rg e o f p o ly mer on t h e to p o f th e c o lu m n . U n f o r t u n a t e l y t h e r e i s no a d s o r p t i o n is o t h e r m d a t a on t h i s p a r t i c u l a r sy s te m , | p o l y s t y r e n e - t e t r a l i n - c a r b o n . j By c o m p a rin g T a b le I I w i t h T a b le IV , and F i g . 2 i , j w i t h F i g . *f, one n o t i c e s t h a t i (1 ) t h e b e t t e r t h e s o l v e n t , t h e h i g h e r t h e m o lecu l a r w e ig h t p o r t i o n w h ic h c an be e l u t e d o u t ' (2 ) t h e b e t t e r th e s o l v e n t , t h e g r e a t e r th e t o t a l j I ■ j ! am ount o f t h e poly m er w h ic h c an b e e l u t e d o u t i. | i ! (3 ) i n a d s o r p t i o n c h ro m a to g ra p h y o f p o l y s t y r e n e on i < i i i ! c a r b o n c e l i t e t h e lo w e r m o le c u la r w e ig h t p o r t i o n | w i l l be e l u t e d o u t f i r s t , t h a t i s , t h e h i g h e r j I _______________mo l e c u l a r w e ig h t p o r t i o n i s more s t r o n g l y______ TABLE IV ANALYSIS OF FRACTIONS ELUTED WITH TETRALIN F r a c t i o n number m l. o f e f f l u e n t Cone, o f p o ly s ty r e n e Cone, a t w hich y)Sf> i s m eas. ' c % found Amount o f p o ly s ty r e n e i n th e f r a c t i o n s *H-50 0 .0 9 2 0 .0 9 2 1 .9 0 0 6 . 2x 1 0^ 0 .9 2 x l0 “ 2 g r #5 5 1 -6 0 0.2^3 0 .1 2 2 1 .6 7 5 5 .3 x l 0 5 2 .^ 3 ,f ## 61-70 0 .1 6 6 0.083 1 .5 6 ^ *+.8x 1 0^ 1 .6 6 • » j #7 7 1 -8 0 0 .1 1 0 0 .1 1 0 1 .5 5 7 *+.8x 1 0^ 1 .1 0 " #8 8 1 -9 0 0 .0 7 7 0 .0 7 7 1 .6 3 8 5 . 1x 1 0^ 0 .7 7 " | #9 9 1-100 0 . 0M+ 0 .0 8 8 1 . 7^2 5 .5 x 1 0 ^ O.Mf « 1 #10 1 0 1 -1 1 0 0 . 02*f 0 . 0^8 1.913 6 .3 x 105 0 . 2*f " j #11 1 1 1 -1 2 0 0 .0 2 0 0 . 0*f0 1.9 7 3 6 . 5x 10^ 0 .2 0 “ ! 1 i C r t 00 TO CO 50 o fcmwr * o 4 0 X 3 o 3 0 u- 20 10 Mv .. _______ -- 1 AMT ' • " i t i ___ 1 1 r- w i f t i • — ■ n l Ur * N t 2 • o * t— 2 -« c 20 40 < ® 0 80 fO 0 f 20 140 EFPLUEKT fK ML. ^ is * A ORROMATOSRAM OF POLYSTYRENE ON CARBON-^CELITE USING TETRALIN AS- ELUENT a d s o rb e d ( h e l d ) by th e a d s o r b e n t . S te p w is e E l u t i o n w ith S e v e r a l S o l v e n t s . B ased on t h e i n f o r m a t i o n o b t a i n e d above one m ig h t e x p e c t a b e t t e r s e p a r a t i o n o f p o l y s t y r e n e by r u n n in g t h e colum n u n d e r th e f o l l o w i n g c o n d i t i o n s : D e p o s it t h e p o ly m e r m ix tu r e on t h e a d s o r b e n t fro m a p o o r s o l v e n t , and e l u t e s t e p w i s e l y w i t h a b e t t e r s o l v e n t and t h e n w i t h t h e b e s t s o l v e n t l a s t . The e x p e rim e n t w as c a r r i e d o u t u n d e r t h e f o llo w in g i | c o n d i t i o n s : j | a d s o r b e n t : e a r b o n - c e l i t e , 32 g . ! co lum n: I n t e r n a l d ia m e te r 2 .3 cm .; h e i g h t 2 9 .5 em. I I sa m p le a p p l i e d : G .201 g a s a 0.503$MEK s o l u t i o n i t j M e th y l e t h y l k e to n e was f i r s t u s e d f o r e l u t i o n . A f t e r 100 I m l. o f e f f l u e n t was c o l l e c t e d , t h e s o l v e n t w as ch an g ed r j j ; | t o t o l u e n e . P o l y s t y r e n e was n o t e l u t e d o u t i n th e f r a c t i o n s < " I , u n t i l t h e 2 4 th f r a c t i o n was c o l l e c t e d . A f t e r th e d i s a p p e a r - i ' j I a n c e o f p o l y s t y r e n e ( a t t h e 3 3 rd f r a c t i o n ) t h e s o l v e n t wasi ! ' ! ; a g a i n chan g ed t o t e t r a l i n . The a p p e a ra n c e o f p o l y s t y r e n e ! I ' i ; i n t h e f r a c t i o n s was fo u n d t o be r e p r o d u c i b l e w i t h i n 20 m li | ‘ ■ S in c e a m ix tu r e o f s o l v e n t s i s u s e d , t h e c o n c e n t r a - | i 7 I ; 5 i t i o n o f e a c h f r a c t i o n c a n n o t be m e a su re d by m eans o f 1 I ; i r e f r a c t o m e t r y . The f i r s t s e r i e s o f f r a c t i o n s w ere t r e a t e d ! | j j by m ethod (1 ) s i n c e t h e s o l v e n t s w ere r e l a t i v e l y v o l a t i l e ! i • ■ . ■ I ! and t h e se c o n d s e r i e s o f f r a c t i o n s by m ethod (2 ) a s d e s - ! ! - ! c r i b e d b e f o r e . i ! I | The r e s u l t s o f a n a l y s i s a r e shown i n T a b le V and 1 F i g . 5 and F i g . 6 . H e re , a g a i n , o n ly a s m a ll p o r t i o n o f k 10 o r d e r i n m o le c u la r w e ig h t w as e l u t e d by t o l u e n e and i t h e g r e a t e r p a r t o f t h e p o l y s t y r e n e o f h i g h e r m o le c u la r w e ig h t w as e l u t e d o u t i n t h e o r d e r o f i n c r e a s i n g m o le c u la r w e ig h t w i t h i n t h e same s o l v e n t e l u t i o n and on c h a n g in g * t h e s o l v e n t t o a b e t t e r o n e . I n t h i s e x p e rim e n t 77% o f t h e p o ly m e r was r e c o v e r e d . T h ese r e s u l t s a r e q u i t e co n s i s t e n t w i t h t h e c o n c l u s i o n s o b t a i n e d b e f o r e and a r e com p l e t e l y r e p r o d u c i b l e ( t h e r e c o v e r y s c a t t e r i n g a ro u n d 8 o $ ) .j The o b s e r v a t i o n s o b t a i n e d h e r e w i l l becom e c l e a r e r | i f we c o n s i d e r t h e a d s o r p t i o n b e h a v io r o f p o l y s t y r e n e j ! e s t a b l i s h e d by some o t h e r w o r k e r s . H obden and J e l l i n e k 2 '7 I I 1 h av e c a r r i e d o u t t h e s t u d y o f th e a d s o r p t i o n i s o t h e r m o f p o l y s t y r e n e o n to c a rb o n fro m m e th y l e t h y l k e to n e s o lu tio n ® J e n c k e l and Rum bacbr h a v e g iv e n th e a d s o r p t i o n i s o t h e r m f o r th e p o l y s t y r e n e - t o l u e n e - c a r b o n s y s te m . From b o th s t u d i e s i t c a n be c o n c lu d e d t h a t m ore p o l y s t y r e n e w i l l b e i | a d s o rb e d fro m m e th y l e t h y l k e to n e s o l u t i o n t h a n fro m ; i t o l u e n e . The same c o n c l u s i o n t h a t m ore p o ly m er w i l l be I a d s o r b e d fro m t h e p o o r s o l v e n t was a l s o o b t a i n e d by Siraha, I F r i s c h and E i r i c h 2^ b a s e d on t h e s t a t i s t i c a l t r e a t m e n t o f ’ ' ( { : th e a d s o r p t i o n o f f l e x i b l e p o ly m e r s . I f one r e c a l l s t h a t | j e l u t i o n i s , e s s e n t i a l l y , a r e v e r s e p r o c e s s t o t h e a d s o r p - j ! t i o n , t h a t i s , i t c a u s e s th e s u b s ta n c e t o p a s s from t h e | j 27 R. Sim ha, H. F r i s c h and E. E i r i c h , J . P h y s . Ghem. ! SZ (1 9 5 3 ) " “ l _ _________________ ________________________________________________ _____ TABLE V ANALYSIS OF FRACTIONS ELUTED STEPWISELY WITH THREE SOLVENTS F r a c t i o n number ral. o f e f f l u d n t Cone, o f p o ly s ty r e n e Cone, a t w hich tjsp i s m eas. "tysp e K found Amount o f p o ly s ty r e n e i n th e f r a c t i o n s #1# #23 0-2 3 0 - - - - m m §2k 231-2^0 0 .0 3 9 0 .0 7 8 0 .2 1 3 7 3 A x lO If 0 .3 9 x l0 “ 2 g r # 2 5 2^-1-250 0.053 0.06** 0 . 2^11 ^f.OxlO^ 0 .5 3 M #26 251-260 0 .0 3 8 0 .076 0 . 27V1 0 .3 8 ” m 261-270 0 .0 3 9 0.078 0 .3 1 9 1 ' 5 .8x 10^ 0 .3 9 ” #28 271-280 0 .0 3 1 O.O62 0 .^ 6 2 2 9 .5 x 1 0 ^ 0 .3 1 1 1 #29 281-290 0 .0 2 8 0 .0 5 6 O.H623 9 .6 x 1 0 ^ 0 .2 8 « #30 291-300 0 .0 2 2 O.OMt 0 . W 5 ip 9.6x10" 0 .2 2 « #31 301 -3 1 0 0 .0 1 6 0 .0 3 2 0 .5 1 1 ^ 1 .1 x 1 0 * 0 .1 6 " #32 3 I I - 3 2 O 0 .0 1 5 * 0 .0 3 0 O .5V06 1 .1 x 1 0 * O.1 5 " # 3 3 -^ 2 321-^-20 - - - - - TABLE V ( CONTINUED) ♦ F r a c t i o n number m l. o f e f f l u e n t Gone, o f u o l y s ty r e n e Cone, a t w hich ^ Sp i s m eas. ^sp e found Amount o f p o ly s ty r e n e i n th e f r a c t i o n s m b 21-1+30 0 .2 1 2 0.b96S l . l x l O 5 2 .1 2 x l0 ’ 2 g r # * - i b 3 1 -b b 0 0 .3 3 1 ' o . % m " 1 .3 1 6 3 .8 x 1 0 ^ 3 .3 1 n b b l- b 5 0 0.21+7 l X v 0 . 12b 1 .5 9 0 b .9 x l 0 ^ 2.1+7 tt b 5 i- b 6 o 0 .1 8 5 0 .0 9 2 1 .7 1 7 5 .6 x 1 0 ^ 1 .8 5 H #*■7 b 6 l- b 7 0 0 .1 2 b 0.1 2 b 1 .9 3 5 6 .b x l0 ^ 1.2b- ir # t8 b 7 i - b 8o 0 .0 5 5 0 .1 1 0 2.0 b 6 6 .8 x 1 0 ^ 0 .5 5 n b 8 l- b 9 0 0 .0 3 9 0.0 7 8 2 .090 7 .1 x 1 0 ^ 0 .3 9 n #50 b 9 1 -5 0 0 0.023 0.0b6 2 .2 5 2 7 .8 x 1 0 ^ 0 .2 3 tt #51 501-510 - - - - 0 .1 0 I! #52 511-520 - - - m m — <1,10 If so 7 0 Go * ° 5b * & 40 x o o 30 > IX 20 I 0 0 r— r --------M v ---------- AMT r i i —...— i • • — n i...... • 1 r m *i r - . . . 3 * ! < M ‘ p ! H Z < EFFLUENT fN ML. F i g . $ CHROMATOGRAM OF POLYSTYRENE ON CABON-CELITE USING SUCCESSIVELY MEK,TOLUENE AND TETRALIN AS ELUENTS it* T o t a l WEIGHT 1 4 0 v xio4 F i g . 6a TOTAL WEIGHT{%) VS.Mv PLOT OF F ig . 5 ST G 4 2 0 i 5 10 M v *10* F i g . 6b dW/dMy : T VS. My PLOT OF F ig . 6a a d s o r b e d l a y e r i n t o s o l u t i o n a g a i n , o n e r e a c h e s th e c o n c l u s i o n t h a t t h e b e t t e r s o l v e n t w ould e l u t e m ore p o l y - ■ i mer o u t t h a n t h e p o o r o n e . i I A t t h i s s t a g e one m ig h t a s k , i f th e f o r e g o i n g j d i s c u s s i o n i s c o r r e c t , why i s o n ly a s m a ll p o r t i o n of p o l y s t y r e n e h a v in g th e m o le c u la r w e ig h t o f th e o r d e r o f 101' e l u t e d o u t b y t o l u e n e ? T h is q u e s t i o n c a n b e answB&ed, th o u g h q u a l i t a t i v e l y , a s f o l l o w s . I t i s g e n e r a l l y b e lie v e c . i t h a t , i n t h e p r o c e s s o f t h e a d s o r p t i o n o f p o ly m e rs , t h e \ d e p o s i t i o n o f t h e w h o le c h a i n on t h e s u r f a c e o f a d s o r b e n t j i i s e x tr e m e ly u n l i k e l y and o n ly a f r a c t i o n o f t h e t o t a l j I v ! | num ber o f t h e c h a i n se g m e n ts w i l l be a n c h o re d o n t h e s u r f a c e . T h ese fo rm a n c h o r s o f v a r y in g l e n g t h w h ic h a r e s e p a r a t e d by p o r t i o n s e x te n d in g i n t o t h e s o l u t i o n s i n th e fo rm o f l o o p s . S t a t i s t i c a l c o n s i d e r a t i o n s ^7 showed t h a t h i g h m o le c u la r w e ig h t p o ly m e rs w i l l b e m ore s t r o n g l y j | a d s o r b e d t h a n lo w e r o n e s . T h e r e f o r e , d u r i n g th e e l u t i o n ! ' { p r o c e s s when t h e f r e s h t o l u e n e comes a lo n g and comes i n 1 c o n t a c t w i t h p o ly m e rs a d s o r b e d on t h e colum n, t h e lo w e r m o le c u la r w e ig h t members b e in g w e a k ly a d s o rb e d may be d e s o rb e d by th e t o l u e n e b u t some p a r t o f them a r e e n ta n g le d | w i t h i n th e f l e x i b l e c o i l s o f t h e h i g h e r m o le c u la r w e ig h t j m em bers. I n o t h e r w o rd s , t o l u e n e , a lt h o u g h i t i s a b e t t e r s o l v e n t t h a n m e th y l e t h y l k e to n e , i s n o t a good enough 1 s o l v e n t t o c a u s e t h e h i g h e r m o le c u la r w e ig h t c o i l s t o | | expand t o f r e e th e low m o le c u la r w e ig h t p o r t i o n s . T h is e x p l a n a t i o n may b e p i c t u r e d more c l e a r l y by i n v e s t i g a t i n g T a b le V. F i g . 5 and F i g . 6 , w h e re t e t r a l i n , th e b e s t s o l v e n t u s e d i n t h i s s t u d y , e l u t e d p r a c t i c a l l y o f t h e p o l y s t y r e n e w h ic h re m a in e d i n t h e colum n a f t e r th e t o l u e n e e l u t i o n . H ow ever, t h i s e x p l a n a t i o n s h o u ld b e p ro v e d by p e r f o r m in g a n e x p e r im e n t u s i n g p o l y s t y r e n e f r a c t i o n ( 6 . 0 x 10^ ) t o se e w h e th e r i t c a n be e l u t e d c o m p le te ly o u t o f t h e colum n w i t h to lu e n e * E l u t i o n w i t h M ixed s o l v e n t s . I n o r d e r t o im p ro v e t h e e f f e c t i v e n e s s o f t h e s e p a r a t i o n o f p o l y s t y r e n e , t h e i m ixed s o l v e n t s w h ic h w ere a r r a n g e d i n o r d e r o f i n c r e a s i n g t h e s o l v e n t power w ere u s e d f o r e l u t i o n . I n p r a c t i c e , t h e colum n w as r u n u n d e r t h e f o l l o w i n g c o n d i t i o n s a d s o r b e n t s c a rb o n and c e l i t e 3 2 g r . colum ns I n t e r n a l d ia m e te r 2 .3 cm. 5 h e i g h t 2 9 .3 cm. sam p le a p p l i e d : 0 .2 0 7 g r . a s 0 .5 1 8 $ MEK s o l u t i o n . A f t e r t h e a p p l i c a t i o n o f th e p o l y s t y r e n e m ix tu r e s o l u t i o n t o t h e t o p o f t h e colum n w h ic h w as made w i t h m e ty l e t h y l k e to n e , th e colum n was t r e a t e d i n th e same m anner a s d e s c r i b e d b e f o r e . The e l u t i o n was s t a r t e d w i t h t o l u e n e t o e l u t e t h e p o l y s t y r e n e h a v in g th e m o le c u la r w e ig h t o f th e k ! o r d e r o f 10 . P o l y s t y r e n e a p p e a re d i n the. e l u a t e a t 2 3 rd f r a c t i o n . T h is was c o n s i s t e n t w i t h t h e o b s e r v a t i o n o b t a i n e d b e f o r e . The s o l v e n t was c h an g ed t o 7 5 -2 5 m ix t u r e o f t o l u e n e and t e t r a l i n a f t e r 28t h f r a c t i o n was c o l l e c t e d . 5 0 -5 0 m ix tu r e o f t o l u e n e and t e t r a l i n w as u s e d t o o b t a i n a n o th e r f i v e f r a c t i o n s , w h ic h w as f o llo w e d by c h a n g in g t h e s o l v e n t t o 2 5 -7 5 m ix tu r e o f t o l u e n e and t e t r a l i n t o c o l l e c t a f u r t h e r f i v e f r a c t i o n s , A f t e r t h i s , t h e p u r e t e t r a l i n was u s e d f o r e l u t i n g t h e h i g h e r m o le c u la r w e ig h t p o r t i o n o f p o l y s t y r e n e i n t h e ^column. The f r a c t i o n s w e re t r e a t e d i n t h e same way a s d e s c r i b e d b e f o r e t o o b t a i n th e c o n c e n t r a t i o n o f e a c h f r a c t i o n . The r e s u l t s o f t h i s a n a l y s i s a r e shown i n T a b le V I, P i g . 7 and F i g , 8 . I t i s e v i d e n t fro m b o th T a b le VI and F i g . 7 and 8 t h a t t h e s e p a r a t i o n o f p o l y s t y r e n e i n t h i s c a s e i s much j m ore e f f e c t i v e t h a n t h a t d e s c r i b e d by T a b le V and F i g . 5 j I t ! and 6 . P u re t o l u e n e e l u t e d o u t t h e p o l y s t y r e n e h a v in g i j , i t h e m o le c u la r w e ig h t o r d e r o f 10 , and 7 5 -2 5 m ix tu r e o f ! i t o l u e n e and t e t r a l i n w as a s e f f e c t i v e a s p u r e t o l u e n e | i ( t h e s o l v e n t pow er d i d n o t i n c r e a s e v e r y m u ch ). H ow ever, I " j 5 0 -5 0 m ix tu r e o f t o l u e n e and t e t r a l i n e l u t e d o u t t h e ! j p o l y s t y r e n e h a v in g t h e m o le c u la r w e ig h t o f o r d e r o f 1 0 ^ , ! I and 2 5 -7 5 m ix tu r e o f t o l u e n e and t e t r a l i n , w h ic h i s , a s j a m a t t e r o f f a c t , a s e f f e c t i v e a s p u r e t e t r a l i n , e l u t e d i | o u t t h e p o l y s t y r e n e w i t h t h e m o le c u la r w e ig h t o f th e j o r d e r o f 1 0 ^ . T h is s u g g e s t s t h a t t h i s c h ro m a to g ra p h ic I ) t e c h n i q u e may b e u s e d a s p r e p a r a t o r y p r o c e d u r e f o r t h e f r a c t i o n a t i o n o f p o l y s t y r e n e by u s i n g a l a r g e r colum n o f a d s o r b e n t , a l a r g e r am ount o f sam ple s o l u t i o n and th e j m ixed s o l v e n t s c o n s i s t i n g o f t o l u e n e and t e t r a l i n . ! The f a c t t h a t t h e p o ly m er i s e l u t e d o u t i n th e } t I o r d e r o f i n c r e a s i n g m o le c u la r w e ig h t h a s a l s o b e e n __________ TABLE VI ANALYSIS OF FRACTIONS ELUTED WITH MIXED SOLVENTS Amount o f C o n e, a t M p o l y s t y r e n e F r a c t i o n m l. o f C on e, o f w h ic h * )S p v i n t h e num ber e f f l u e n t p o l y s t y r e h e i s m e a s. ” " \£ — fo u n d f r a c t i o n s $ 2 3 231-2^0 V / ® S-- I.*.'** 0 .028 0 .0 5 6 0 .3 1 7 k .lx ic f r 0 . 28x 10 $2b 2^1-250 0 .0 5 5 0 ,0 5 5 0 .2 3 1 3 .8 x 1 0 ^ 0 .5 5 #25 251-260 0 . 08& 0 . 08J+ 0 .2 3 7 3 .9 x 1 0 ^ 0.8if , #2$ 261-270 0 .078 0 .0 7 8 0.2 6 7 ^ .6 x 1 0 ^ 0 .7 8 #27 271-280 0 .0 5 7 0 .0 5 7 0 .2 6 0 j ^ M-.^xlO 0 .5 7 #28 281-290 0 .0 3 1 0 .0 6 2 0 .5 0 0 1 .1 x 1 0 ^ 0 .3 1 #29 291-300 0 .0 1 1 0 .0 2 2 0 .7 8 0 1 .9 x 1 0 ^ 0 .1 1 #30 301-310 0.0 0 8 - mm - 0 .0 8 # 3 1 -# 3 2 311 -330 0 .0 1 1 0 .0 2 2 0 .7 k 0 1 .8 x 1 0 ^ 0 .1 1 #33-#3*+ 331-350 0 .0 1 0 - - - 0 .1 0 # S S -# 3 6 351-370 0 .0 0 7 mm — 0 .0 7 TABLE VI (CONTINUED) F r a c t i o n num ber m l. o f e f f l u e n t C on e, o f p o l y s t y r e n e C o n e . a t ■ © h i c k H s f i k i m e a s . % p/t My fo u n d Amount o f p o l y s t y r e n e i n t h e f r a c t i o n s #37 371-3 80 0.1'Cfc O .IO V 1 .2 3 0 3 .5 x 1 0 ^ l.Cfc-xlo” •2 gr #38 3 81 -390 0 .1 9 2 0 .0 9 6 1 .2 2 9 3 . 5x10^ 1 .9 2 n #39 3 9 1 -^ 0 0 0.1^0 0 .0 9 2 1 .0 0 9 2 ,7 x 1 0 ^ 1 M v # > (■ 0 le i-^ io 0 .1 3 ^ O . ^ 1 .8 0 1 5 .8x10 ^ 1.3>+ 1 1 ^ 11-^20 O.OgO 0 .0 8 0 2.0^9 6 .9 x 1 0 ^ 0 .8 0 r i #^2 ^ 21-^30 0 .2 1 7 0 .1 0 8 3 .2 2 9 1.25x10- ■2.17 H #► 3 i+ 31- ^ o °.15^ 0 .0 7 7 3 .2 3 0 1.25 x10^ 1 .51 * - 1 ! m+i— ^-50 0 .0 6 5 0 .0 6 5 3 .2 3 2 1 . 26x l 06 0 .6 5 1 ! if5l-^6o 0 .0 3 5 0 .0 7 0 3 .1 8 8 6 1 . 23x 10 0 .3 5 M m -4*7 W l-lfg O 0 .0 3 6 0 .0 7 2 3 . 2 ^ 5 6 1 .2 7x10 0 .3 6 ri m - m ^ 81-520 O .CkO 0 .0 8 0 3 .6 7 6 I.* f8 x l0 6 0 A 0 M # 5 2 -# 5 5 521-560 0.013 - - « • 0 , 0 .1 3 t» FoilNfc |4o i lo I 10 I 00 ^0 % % 0 K 70 6o > 50 40 30 20 to — — 0 - _____________ F i g . 7_____________ CHROM ATOGRAM OF POLYSTYRENE ON CARBON-CELITE USING MIXED SOLVENTS AS ELUENTS AM T - E Z Z I £oo 0 * -240 -?6o iS o 3o» 3*0 340 36o J J o 4-«o 4*o 4 4 ^ ” 46o"~46o Wo i*<K j - u r ■ i u .. ----- --------- dr h- z m < \ m Jto E FFLU6KT I H ML, T O TM WEI frHT j % 0 7o 5© 2o 10 0 2 lo 20 10 M v x ‘°4 F i g . 8a TOTAL WEIGHT 0 0 VS. PLOT OF F i g . 7 o » -W X to i r s € 4- 2 o 1 0 20 M « * »o So loo F i g . gb dW/dMy VS. M v PLOT OF F ig . 2a |oi | o b s e r v e d b y p r e v i o u s w o rk e rs T h is phenom enon may be a t t r i b u t e d t o t h e p o s s i b i l i t y t h a t t h e lo w e r m o le c u la r w e ig h t &gm010gs a r e m ore w e a k ly h e l d by t h e a d s o r b e n t . A n o th e r p o s s i b i l i t y (w h ic h d o e s n o t e x c lu d e t h e f i r s t ) d e p e n d s o n t h e f a c t t h a t e l u t i o n c an be i n t e r p r e t e d a s a r e v e r s e p r o c e s s t o t h e d e p o s i t i o n o f th e p o ly m e r. Thus e l u t i o n i s a s o l u t i o n p r o c e s s o f t h e d e p o s i t e d p o ly m er by t h e e l u t i n g s o l v e n t . I t i s a m a t t e r o f e x p e r i e n c e t h a t lo w e r m o le c u la r w e ig h t hom o lo g s a r e m ore r e a d i l y s o l u b l e t h a n h i g h e r m o le c u la r w e ig h t h o m o lo g s. T h is c an b e s e e n | by t h e f o l l o w i n g c o n s i d e r a t i o n . N am ely, we may c o n s i d e r t h e e q u i l i b r i u m b e tw e e n poly m er d e p o s i t e d on th e a d s o r b e n t s and i t s s o l u t i o n f lo w in g down t h e co lu m n . The G ib b s f r e e i. e n e rg y o f t h e p u r e p o ly m e r i s a p p r o x im a te ly p r o p o r t i o n a l t o t h e c h a i n l e n g t h , h e n c e t h e e q u i l i b r i u m c o n d i t i o n w i l l 28 | assum e t h e fo rm I n v 2 + ( 1 - x ^ + i , x v 12 5 X KSo l i d (6 ) | w h e re v ^ i s t h e volum e f r a c t i o n o f s o l v e n t , v 2 i s t h e ! volu m e f r a c t i o n o f p o ly m e r, D c,is th e i n t e r a c t i o n e n e rg y 1 1 l | p a r a m e t e r , x i s t h e num ber o f se g m en ts o f p o ly m e r, and 1 . ; i s a c o n s t a n t d e p e n d in g o n ly on t h e t e m p e r a t u r e i ^ b u t i s in d e p e n d e n t o f x . F o r v e r y d i l u t e s o l u t i o n s and ^ H. K r u y t, C o l l o i d S c ie n c e V o l. 2 . E l s e v i e r P u b l i s h i n g C o ., New Y o rk , 1 9 ^ 9 . p . 7 9 . \ 56 a l a r g e x w h ic h i s t h e c a s e we a r e d e a l i n g w i t h , v , 1 ^. V | - I - V* Z S S I we g e t v 2 « e “ aX w h e re a a ( * , - 1 -K s o l i d ^ * ^ i s s o l u b l e a t a ll,] 0 ^ v 2 < l , and a ^ O . T hus f o r p o ly m e rs w i t h x-^ and x 2 se g m e n ts w h ere x ^ > x 2 , we h a v e v 2(xi) -a(x 1-x 2) < i i v 2 Cx2 ) T h is m eans t h a t t h e low m o le e u la r w e ig h t hom olo gs a r e m ore s o l u b l e t h a n t h e i r h i g h e r h o m o lo g s. A ls o t h e r a t e o f s o l u t i o n i s g e n e r a l l y g r e a t e r f o r t h e lo w e r m o le c u la r w e ig h t h om ologs o f a p o ly m e r. I t i s o f i n t e r e s t t o n o te a s t a t e m e n t h e r e on th e c h o ic e o f s o l v e n t f o r p o ly m e r. I n p r i n c i p l e , t h e p o ly m e r- s o l v e n t p a i r i s c h a r a c t e r i z e d by t h e i n t e r a c t i o n e n e rg y p a r a m e t e r , ^ , by w h ic h t h e c h o ic e o f t h e s o l v e n t w i l l be ] m ade. H ow ever, i t w i l l be m ore c o n v e n ie n t t o c h o o se th e j | s u i t a b l e p o l y m e r - s o l v e n t p a i r v i s e o m e t r i c a l l y b a se d on i t h e a rg u m e n t 2 9 -3 0 t h a t t h e l a r g e r t h e a , M a r k - S ta u d in g e r - Houwink c o n s t a n t , a p p e a re d i n E q. (1 ) f o r a g iv e n p o ly m e r- s o l v e n t p a i r a t a g iv e n t e m p e r a t u r e , t h e b e t t e r th e s o l v e n t i S in c e t h e c o n s t a n t s , a , f o r v a r i o u s p o l y m e r - s o l v e n t p a i r s ^1 c a n be fo u n d e a s i l y i n t h e l i t e r a t u r e , t h i s c r i t e r i o n 29 T . Fox and P . F l o r y , J . P h y s . C o l l o i d Chem. . 5^ 1 9 7 , (1 9 ^ 9 ) 3 ° T . Fox and P . F l o r y , J . Am- Chem. S o c . 2 1 1 9 0 9 (1 9 5 1 ) 31 h . S t u a r t , D ie P h y s ik d e r Hoch P o ly m e re n Band I I " S p r in g e r - V e r la g ^ — B e r ± in y — T953~P'i ------------------------------------------- 57 i s m ore u s e f u l . P a r t i t i o n colum n c h ro m a to g ra p h y o f p o l y s t y r e n e , i n v iew o f t h e f a c t t h a t t h e p a r t i t i o n colum n c h ro g ja to - g ra p h ^ c t e c h n i q u e fo u n d e d by M a r tin and Synge32?33 h a s b e e n s u c c e s s f u l l y a p p l i e d t o t h e s e p a r a t i o n o f n a t u r a l l y o c c u r r i n g p o ly m e rs , i . e . p r o t e i n e s and am ino a c i d s , an a tt e m p t h a s b e e n made t o a p p ly t h i s t e c h n i q u e t o th e s e p a r a t i o n o f p o l y s t y r e n e s . The m ost i m p o r t a n t f a c t o r i n t h i s t e c h n i q u e i s t o o b t a i n a s u i t a b l e im m is ib le s o l v e n t p a i r i n w h ic h p o l y s t y r e n e i s s o l u b l e . The s o l u b i l i t y o f p o l y s t y r e n e i n v a r i o u s s o l v e n t s h av e b e e n sum m arized by H i l d e r b r a n d and Scott3lf a s shown i n th e t a b l e b e lo w . S o l u b i l i t y o f p o l y s t y r e n e S o l v e n t s S o l u b i l i t y E t h y l e t h e r s w e l l s . C y c lo h e x a n e s o l u b l e above 30C S e c - b u t y l b ro m id e s o l u b l e N - b u ty l b ro m id e s o l u b l e C arb o n t e t r a c h l o r i d e s o l u b l e M e th y l e t h l k e to n e s o l u b l e T o lu e n e s o l u b l e I 3 2 A. M a r tin and S y n g e, B iochem . J . 37 79 (1 9 ^ 3 ) 33 a . M a r tin , A nn. N. Y. A cad . S c i . 2^9 (1 9 ^ 8 ) 3^ J . H i l d e r b r a n d and R . S c o t t , The S o l u b i l i t y o f N o n e l e c t r o l y t e s . R e in h o ld P u b l i s h i n g C o ., New Y ork: (1 9 5 0 ) i P . 373. S o l v e n t s S o l u b i l i t y B e n z e n e C h lo r o fo r m 1 . 2 d i e h l o r o e t h a n e 1 . 2 d ib r o m o e t h a n e 1 . 2 d ib r o m o e t h y le n e D io x a n e C a rb o n d i s u l f i d e N it r o b e n z e n e - b r o m o n a p h t h a le n e N it r o p r o p a n e N i t r o e t h a n e A f t e r e x t e n s i v e t e s t s n o s u i t a b l e s o l v e n t p a i r c o u ld b e f o u n d fr o m t h o s e s o l v e n t s l i s t e d a b o v e . T h e r e f o r e , i t ■was c o n c l u d e d , f o r t im e b e i n g , t h a t t h e r e i s l i t t l e j p o s s i b i l i t y o f c a r r y i n g o u t t h e p a r t i t i o n c o lu m n c h r o m a to g r a p h y o f p o l y s t y r e n e . s o l u b l e s o l u b l e s o l u b l e s o l u b l e s o l u b l e s o l u b l e s o l u b l e s o l u b l e s o l u b l e s o l u b l e s w e l l s CHAPTER IV I " . MEASUREMENT OF VISCOSITY AVERAGE MOLECULAR WEIGHT OF POLYMER SOLUTIONS OF UNKNOW N CONCENTRATION* As a l r e a d y shown i n t h e l a s t c h a p t e r , much e f f o r t h a s t o be d e v o te d t o t h e d e t e r m i n a t i o n o f t h e c o n c e n t r a t i o n s o f e l u a t e s i n o r d e r t o a p p ly E q. (1 ) by w h ic h t h e v i s c o s i t y a v e r a g e m o le c u la r w e ig h t c a n be o b t a i n e d . T h e re f o r e , i t i s o f g r e a t im p o r ta n c e t o d e v e lo p a t e c h n iq u e ! ! fro m w h ic h t h e a v e r a g e m o le c u la r w e ig h t o f p o ly m e r s o lu tio n j o f unknown c o n c e n t r a t i o n c a n be d e te r m in e d v i s c o m e t r i e a l l y . j i I One p o s s i b l e w ay i n w h ic h t h i s m o le c u la r h e i g h t c an b e d e te r m in e d fro m c e r t a i n known v i s c o s i t y d a t a a b o u t th e s o l u t i o n o r i t s co m p o n en ts w i l l be d e s c r i b e d h e r e a s an a d d i t i o n a l s tu d y i n t h e i n v e s t i g a t i o n o f c h ro m a to g r a p h ic 1 t e c h n i q u e f o r t h e s e p a r a t i o n o f h i g h p o ly m e r s . I . P r i n c i p l e F o r t h e sa k e o f c o n c r e t e n e s s , we c o n s i d e r t h a t t h i s p r i n c i p l e i s , s a y , a p p l i e d t o t h e s tu d y o f th e a d s o r p t i o n i I c h ro m a to g ra p h y o f a p o ly m e r i n s o l u t i o n b y f r o n t a l a n a l y s i s , i ! I n t h i s c a s e we c an s p e a k o f an o r i g i n a l s o l u t i o n , i . e . ! ! j t h e p o ly m e r s o l u t i o n b e f o r e i t s p a s s a g e t h r o u g h t h e * T h is p a r t o f w ork h a s b e e n p u b l i s h e d i n H. F r i s c h | and S . Yeh, J . P o ly m er S c i . 20 *f31 (1 9 5 6 ) c h ro m a to g r a p h ic colum n, and a p o r t i o n o f t h e o r i g i n a l s o l u t i o n t h a t h a s a l r e a d y p a s s e d th r o u g h t h e colum n, w h ic h we r e f e r t o o n ly a s t h e s o l u t i o n ! B e f o re p r o c e e d in g i t s h o u ld h e re m a rk e d h e r e t h a t t h e v i s c o s i t y a v e r a g e m o le c u la r w e ig h t o f p o ly m er i n t h e s o l u t i o n c a n h e d e te r m in e d i n t h e u s u a l m anner fro m t h e i i n t r i n s i c v i s c o s i t y i f t h e c o n c e n t r a t i o n o f t h e s o l u t i o n c a n he s e p a r a t e l y d e te r m i n e d . As d i s c u s s e d b e f o r e , two ways o f d o in g t h i s h a v e b e e n r e c e n t l y s u g g e s te d i n th e ( l i t e r a t u r e . The f i r s t , u s e d by C la e s s o n ? , i s by m eans o f i j m i c r o r e f r a e t o m e t r y w h ic h h a s t h e a d v a n ta g e o f n o t d e s t r o y - > lin g t h e s o l u t i o n w hose r e f r a c t i v e in d e x in c r e m e n t i s m e a s u r- j jed , b u t w h ic h c a n n o t be a p p l i e d i f th e d i f f e r e n c e i n j r e f r a c t i v e in d e x e s o f t h e s o l u t i o n and th e s o l v e n t i s to o I s m a il. The se c o n d m ethod i n v o l v e s t h e r e c o v e r y o f t h e i { d is s o lv e d p o ly m er fro m t h e s o l u t i o n b y , s a y , e v a p o r a t i o n i ((u n d e r vacuum ) o f t h e s o l v e n t s u b s e q u e n t t o t h e s p e c i f i c I { v i s c o s i t y m e a su re m e n ts1 0 . The o b v io u s d i s a d v a n t a g e o f t h i s i (m ethod i s t h a t t h e s o l u t i o n m ust be d e s t r o y e d . F u r th e r m o r e , t h e m ethod c e a s e s t o be a c c u r a t e i f e i t h e r t h e s o l u t i o n , {whose volum e may be v e r y s m a ll ( 1 - 1 .5 c . o r l e s s ) i s v e r y ! | d i l u t e o r i f v o l a t i l e d e c o m p o s itio n p r o d u c t s o f th e p o ly m e r I a r e fo u n d d u r i n g t h e v a p o r i z a t i o n . R e tu r n in g now t o t h e o r i g i n a l s o l u t i o n o f po lym er o f known a v e r a g e m o le c u la r w e ig h t S9 i n s o l v e n t No. 1 , we w ith d re w two a l i q u o t s and d i l u t e e a c h o f th em i n t h e r a t i o m l : n w i t h s o l v e n t No. 1 and a d i f f e r e n t s o l v e n t No. 2 , r e s p e c t i v e l y . S o lv e n t No. 2 m ust be m i s c i b l e w i t h b o th s o l v e n t No. 1 and th e p o ly m e r i n t h e c o n c e n t r a t i o n r a n g e u s e d , and p r e f e r a b l y one o f t h e s o l v e n t s s h o u ld b e a much b e t t e r s o l v e n t f o r t h e p o ly m e r t h a n t h e o t h e r s o l v e n t . Thus we h a v e two s o l u t i o n s we w i l l c a l l o r i g i n a l s o l u t i o n No. 1 (w hose s o l v e n t i s p u r e s o l v e n t No. 1 ) and o r i g i n a l s o l u t i o n No. 2 (w hose s o l v e n t i s a l s n m ix tu r e o f s o l v e n t s No. 1 and No. 2 ) w hose c o n c e n t r a t i o n s o f p o ly m e r i n gram s p e r 100 m l. a r e e q u a l b u t w hose m a g n itu d e C i s n o t known. ! | We now m e a su re t h e s p e c i f i c v i s c o s i t i e s T>°Sp (1 ) and (2 ) o f o r i g i n a l s o l u t i o n No. 1 and No. 2 , r e s p e c t i v e l y . T h e se a r e g itfe n i n t h e f i r s t a p p r o x im a tio n t o te r m s o f j ■ o r d e r by t h e H u g g in s r e l a t i o n s ? | = E v 3 ‘ c *K\i-nV.)ic1 I . \ x (7 ) i % , " > = t ' T , c- w h e re , and m i a r e t h e i n t r i n s i c v i s c o s i t i e s and 4e, and A z c o n s t a n t s f o r o r i g i n a l s o l u t i o n s No. 1 and No. 2 , r e s p e c t i v e l y . I f t h e s o l u t i o n s a r e s u f f i c i e n t l y d i l u t e ( i . e . n i s c h o s e n l a r g e e n o u g h ) t h e n t h e q u a d r a t i c te rm s 5 I | c a n b e n e g l e c t e d w i t h o u t s e r i o u s e r r o r . To c o n firm t h a t t h i s i s t h e c a s e , we c a r r y o u t m e a su re m e n ts o f th e s p e c i f i c v i s c o s i t i e s o f t h e tw o s o l u t i o n s a s t h e y a r e b o th d i l u t e d i n some se q u e n c e su c h a s 0 .7 5 C> 0 .5 0 C, 0 .2 5 C, 0 . 1 C, e tc ', by a d d in g s o l v e n t No. 1 and a l : n m ix tu r e o f s o l v e n t s No. 1 and No. 2 , r e s p e c t i v e l y . S in e e e q u a t i o n (7„ r e d u c e s t o a l i n e a r r e l a t i o n we f i n d t h a t = t = ^ ' /f> n ; (8 ) i s e x p e r i m e n t a l l y known. I n a s i m i l a r f a s h i o n a l i q u o t s o f th e s o l u t i o n c o n t a i n i n g p o ly m e r w hose a v e r a g e m o le c u la r w e ig h t i s M y. ( ^ M y 5 ) i n s o l v e n t No. 1 a r e d i l u t e d i n t h e r a t i o l s n w i t h s o l v e n t No. 1 and s o l v e n t No. 2 t o g iv e s o l u t i o n N o .l and s o l u t i o n No. 2 o f e q u a l c o n c e n t r a t i o n s . The s p e c i f i c v i s c o s i t i e s (1 ) and (2 ) o f t h e s e s o l u t i o n s a r e d e te r m in e d (an d m aking s u r e a g a i n t h a t we a r e w o rk in g w i t h s u f f i c i e n t l y d i l u t e s o l u t i o n s so t h a t t h e s e a r e l i n e a r i n t h e c o n c e n t r a t i o n ) we c an w r i t e i n a n a lo g y t o e q u a t i o n ( 8 ) ; * = . / ( ? » , <9) j w h e re , a n d ^ T jlg a r a th e i n t r i n s i c v i s c o s i t i e s o f t h e | p a r t i a l l y f r a c t i o n a t e d p o ly m e r My i n p u r e s o l v e n t No. 1 i and a l s n m ix tu r e o f s o l v e n t No. 1 and s o l v e n t No. 2 . E m p i r i c a l l y t h e i n t r i n s i c v i s c o s i t y o f a p o ly m e r i n a g iv e n s o l v e n t c a n be c o r r e l a t e d o v e r s e v e r a l m a g n itu d e s | o f My by m eans o f a S ta u d in g e r-M a rk -H o u w in k r e l a t i o n s u c h a s ; [ T j l = k m " i ■ i w h ere K and a a r e c o n s t a n t s in d e p e n d e n t o f My ( a t l e a s t i n f i r s t a p p r o x im a tio n ) b u t d e p e n d in g on t h e p o ly m e r- OC’ s o l v e n t s y s te m and t h e t e m p e r a t u r e . ' Thus we c a n w r i t e i n f i r s t a p p ro x im a tio n s L 1 )!, = K . Fl*' CVh=^A“l a 0 ° ) m m ; ) r » ] ‘ -- w h e re % , a-j_ and K2 , a ^ a r e t h e c o n s t a n t s f o r t h e p o ly m er ( i n t h e m o le c u la r w e ig h t r a n g e d e s i r e d ) i n s o l v e n t No. 1 and a l s n m ix tu r e o f s o l v e n t No. 1 t o s o l v e n t No. 2, r e s p e c t i v e l y . I n t r o d u c i n g e q u a t i o n (1 0 ) i n t o (8 ) and (9 ) we f i n d i n f i r s t a p p ro x im a tio n s * e % ) ( M : ) (1 1 a ) and s o rs ( l i b ) (12) Thus m e a su re m e n ts o f t h e s p e c i f i c v i s c o s i t y o f a s o l u t i o n o f known m o le c u la r w e ig h t M° i n two s o l v e n t s f o r w h ic h a * j_ and a 2 a r e known a llo w u s t o c a l c u l a t e M v fro m o n ly 35 p . F l o r y , P r i n c i p l e s o f P o ly m er C h e m is tr y . C o r n e l l U n i v e r s i t y P r e s s , I t h a c a , New Y o rk , 195s * • s p e c i f i c v i s c o s i t y m e a su re m e n ts on t h e s o l u t i o n . Knowing a l s o K^ o r we c a n u s e e q u a t i o n (1 2 ) t o d e te r m in e 0 , ' t h e c o n c e n t r a t i o n o f t h e unknown s o l u t i o n , s i n c e t o te r m s I t i s n o t n e c e s s a r y t o know t h e m o le c u la r w e ig h t o f t h e o r i g i n a l s o l u t i o n a s lo n g a s i t s c o n c e n t r a t i o n i s knowji and K^ i s g iv e n a s i s shown b y t h e ab ove r e l a t i o n . I n s t e a d o f u s i n g a se c o n d s o l v e n t , o n e c a n c a r r y o u t s p e c i f i c v i s c o s i t y m e a su re m e n ts a t two d i f f e r e n t t e m p e r a t u r e s , w h e re t h e s u b s c r i p t s 1 and 2 i n e q u a t i o n s (1 1 ) and ( I S ) r e s p e c t i v e l y . So f a r we h a v e n o t commented on t h e p r e c i s i o n o f t h e s u g g e s te d p r o c e d u r e . I t s h o u ld b e c l e a r fro m th e | n a t u r e o f t h e m ea su re m e n t t h a t , a lt h o u g h t h e p r e c i s i o n I h i g h e s t p r e c i s i o n . T h is c a n be s e e n by c o n s i d e r i n g th e m ost p r o b a b l e e r r o r i n t h e r a t i o M^/M®, £(My/M^). p ro d u c e d by x p r o b a b l e e r r o r £ ( x / x Q) i n t h e e x p e r i m e n t a l d e te r m i n a t i o n o f x / x Q: j t h e m ethod i s s a t i s f a c t o r y < i> f a a i s made s u f f i c i e n t l y 2 o f o r d e r G : now | c a n b e im p ro v e d , t h i s m ethod i n t r i n s i c a l l y i s n o t o f t h e w h e re a a s a ^ - a 2 . T hus i f M v < M^, t h e m ethod i s f a i r l y good w h i l e , i f M ^ M y . i t i s p o o r . I n th e c a s e ^ l a r g e I I . EXPERIMENTAL AND RESULTS I n o r d e r t o c o n fir m t h e p r o c e d u r e s u g g e s te d a b o v e , e q u a t i o n s ( 1 1 ) and ( 1 2 ) , t h e f o l l o w i n g e x p e r im e n ts w e re p e rf o r m e d . M a t e r i a l s . S o lv e n ts ? P o ly m e r: j V is c o m e try and r e s u l t s . B e fo re p r o c e e d i n g , t h e ! ! v e r i f i c a t i o n o f e q u a t i o n s (1 1 ) and ( 1 2 ) , t h e c o n s t a n t s K and a a p p e a re d i n t h e e q u a t i o n s m ust b e d e te r m in e d . The K and a v a l u e s i n p u re t o l u e n e and t o l u e n e - m e t h y l e t h y l k e to n e m ix t u r e s w ere d e te r m in e d s e p a r a t e l y fro m ‘ tygp/C ! and C d a t a , o f w h ic h 71 w e re m ea su re d w i t h U b b elohde 1 7 *sp ty p e d i l u t i o n v i s c o m e t e r . -5 T h ese d a t a a r e shown i n i T a b le V I I , i n w h ic h [■*}}, K and a w e re c a l c u l a t e d b y l e a s t s q u a r e m e th o d . To v e r i f y e q u a t i o n s (1 1 ) and ( 1 2 ) , p o l y - s t y r e n e s o l u t i o n s o f known M v (and c o n c e n t r a t i o n s ) w ere 36 W. D a v is , and J . E l l i o t . J . C o l l o i d . S c iT -^ 313 T o lu e n e and m e th y l e t h y l k e to n e w ere u s e d a s s o l v e n t No. 1 and s o l v e n t No. 2 , r e s p e c t i v e l y . The s p e c i f i c a t i o n s f o r t h e s e s o l v e n t s a r e shown i n p p . 2 1 . The p o l y s t y r e n e f r a c t i o n s d e s c r i b e d i n PP® 2 0 'w ere u s e d i n m aking t h e m ix tu r e s o f known c o m p o s itio n s , M^, Mg and M^ a s w i l l be d e s c r i b e d l a t e r . 66 TABLE V II K AND a VALUES FOR POLYSTYRENE AT 25 *c±o, fc S o l u t i o n com p o se d o f % t o l - % MEK P o l y s ty r e n e f r a c t i o n s Cone .,;. . > g r/lO O m l. V c i v l K and a i.5 x io 6 0.i|.12 0 .206 0 .1 3 7 O.1 0 3 0 .0 7 7 k.< 2 4*12 3 .8 1 #•. 69 3 .5 7 3 .3 3 a-- 0 .7 5 4 K=8.1 x % * • io-5 1 0 0 -0 1 1 J 6 .7 x 1 0 ^ O.I4.02 0 .2 1 0 0 .1 4 0 0 .1 0 5 0 .0 7 9 2 .9 9 2.66 2 .5 3 2 .5 1 2.51 2.33 : 1 ! 1 i i 1 i ! 6.0x10^ 0.456 0 .3 4 2 0 .2 7 4 0 .2 2 8 0 .3 3 2 0 .3 2 7 0 .3 2 3 0.321 0 .3 1 2 1 | 1 i.5 x io 6 0 .2 0 8 0 .1 0 4 0.;069 0 .0 4 2 3 .1 9 2 .9 2 2 .8 4 2.62 2 .5 5 a * 0 . 717 ! K r l . l X 1 0 " 4 i I 5 0 -S o 1 j ) 6 .7 x 1 0 ^ O.4 1 8 0 .2 0 9 0 .1 3 9 0 .1 0 5 0 .0 8 4 2 .4 8 2 .1 5 2 .0 9 2.06 . 2.01 1 .8 9 t ! 1 \ 6 .0 x 1 0 ^ 0.408 0.306 . 0 . 2 4 5 0 .2 9 3 0 .2 9 1 0 .2 8 8 0 .2 7 5 j i S i 1 | i 1 1 i.5 x io 6 0 .2 0 4 0.102 0 .0 6 8 O .o 5 l 2 .2 7 2 .1 3 2 .0 7 2 .0 4 1 .9 7 " a *0 .6 6 5 K = 2.3 x j - 4 ! 10 ^ i j | 1 0 -9 0 6 .7 x 1 0 ^ 0 .4 1 2 0 .2 0 6 0 .1 3 7 0 .1 0 3 1 . 69 1 .5 3 1 -4 9 1 .4 6 1*28 i i 6 .0 x 1 0 ^ 0 . 4 l 8 0 .2 5 1 0 .2 0 9 0 .1 7 9 0 .2 4 3 0 .2 3 9 0 . 24o 0 .2 4 0 0.236 e \ i 1 i S 1 ! ; made up i n t o l u e n e ( s o l v e n t No. 1 ) and t o lu e n e - m e th y l i e t h y l k e to n e ( s o l v e n t No. 2) m i x t u r e s . The v i s c o s i t i e s o f t h e s e s o l u t i o n s w ere d e te r m in e d u s i n g m o d if ie d O stw ald ty p e v i s c o m e te r ( t o l u e n e flo w tim e o f 600 s e c . ) . The r e s u l t s o f t h e r a t i o s o f t h e s p e c i f i c v i s c o s i t y m e a su re m e n ts i n c l u d i n g s o l u t i o n s o f t h r e e t y p i c a l p o ly m er m ix t u r e s (Ml o b t a i n e d by m ix in g f r a c t i o n s o f My < = > 1 .5 x 10^ , k and 6 x 10 ; M2 and M3 o b t a i n e d by m ix in g f r a c t i o n s o f My — 1 . 5 x 106 and 6 , 7 x 10 ^) a r e p r e s e n t e d i n T a b le V I I I , j i The X v a l u e s f o r s o l u t i o n s S1-S 5 w e re o b t a i n e d fro m i n t e r - ' o j I p o l a t i n g t h e s p e c i f i c v i s c o s i t y v a l u e s fro m /G v e r s u s C j i sp t i I i d a t a u s e d i n o b t a i n i n g K and a v a l u e s f o r d e s i r e d c o n c e n - ; ! t r a t i o n s i n d i c a t e d i n p a r e n t h e s i s i n T a b le V I I I . The | j q u a n t i t y (XQ) ^ s t a n d s f o r t h e a c t u a l v a l u e o f > a s \ f we s h a l l s e e b e lo w ; u s i n g i t im p ro v e s t h e a p p a r e n t a c c u r a c y ! ; J o f t h i s m e th o d . 1 ! j \ I n t a b l e IX c o m p a ris o n i s made b e tw e e n t h e a c t u a l s i - I j My., c a l c . ) f r o m e q u a t i o n (1 2 ) u s i n g t h e d a t a o f T a b le V I I I . j i ' I n v iew o f t h e known u n c e r t a i n t i e s i n m o le c u la r w e ig h t | d e t e r m i n a t i o n s , t h e i n h e r e n t a p p r o x im a tio n s o f t h i s t r e a t - | m ent and o r d i n a r y e x p e r i m e n t a l e r r o r t h e a g re e m e n t fo u n d i | i s more t h a n s a t i s f a c t o r y . H ow ever, i t s h o u ld be n o t e d j | t h a t t h i s m ethod c a n n o t b e a p p l i e d t o t h e c a s e w here I m ixed s o l v e n t s a r e u s e d a s o r i g i n a l s o l v e n t i n t h e chrom a- ! t o g r a p h y . j TABLE V I I I SPECIFIC VISCOSITY RATIOS AT 2 5 * 0 .1 * 0 S o l u t i o n M v X Cone ; :: g r/lO O m l X *0 (^o^c> 0 S1 \ l . S x l O 6 ( 0 .2 1 7 ) - 1.2614- S2 My 1 .5 x 1 0 ( 0 . 2 0 14.) - 1 .2 6 6 1 .3 0 7 | S~ My 6 . 0 x l 0 6 ( 0 .2 1 7 ) - 1 .1 2 3 1 .1 3 3 ! * v 6 .3 x 1 0 ^ 0 .2 1 7 1 .2 3 7 - ! M \ 8 . IpclO^ 0 . 2014. 1 .2 8 0 - j t r f S o l v e n t N o . l : 100$ t o l u e n e , S o lv e n t Wo.2 : 50 $ t o l u e n e - 5 0 $ MEK, a 0 .0 3 7 M 1 . 5 x l 0 6 (0 .2 0 0 ) - 1 .7 9 1 s 5 M 6 .7 x 1 0 ^ (0 .2 0 0 ) - 1 .7 6 0 ! M o i 8 . 1(.xl 0^ 0 .2 0 0 1.714-9 - \ I 1 S o lv e n t N o . l : 100$ t o l u e n e , S o lv e n t N o .2 : 1 0 $ t o l u e n e - 9 0 ^ MEK, a 0 .0 8 9 69 TABLE IX COMPARISION BETWEEN CALCULATED AND EXPERIMENTAL My U sin g i n E q . (12) S o l u t i o n Xq o f (Xq ) c+q C a lc . * 1 6.3x10^ 8,i|xl0^ Kj. 6.3x10^ S_ — 5 8.2x10 M1 5 6.3x10 3 S3 6.ipd0^ m2 8.35x105 S o - 1.99xl06 m2 8.35x10^ c V 8.53x10^ M3 8.1ptl0^ - 1.2xl06 m3 8,i|.xl0^ s S - 6.3x10^ i CHAPTER V SUMMARY AND CONCLUSION I t i s a w e l l known f a c t t h a t t h e c h r o m a to g r a p h ic a d s o r p t i o n t e c h n i q u e i s a v e r y p o w e r f u l t o o l f o r s e p a r a t i o n o f c l o s e l y r e l a t e d s u b s t a n c e s . H ow ever, i t i s d i f f i c u l t t o a p p ly t h i s t e c h n i q u e t o th e s e p a r a t i o n o f h i g h p o ly m e rs d u e t o t h e f o l l o w i n g f a c t o r s : | | 1 . The am ounts o f p o ly m e rs a d s o rb e d a r e | g e n e r a l l y lo w . j 2 . The r a t e o f a d s o r p t i o n i s s lo w . j i i 3 . No d i s c r e t e zone w i l l b e o b s e r v e d d u e t o th e j c o n ti n u o u s d i s t r i b u t i o n i n m o le c u la r w e ig h t o f t h e h i g h p o ly m e r. j b . H ig h p o ly m e rs a r e c o l o r l e s s and i t i s j g e n e r a l l y d i f f i c u l t t o o b s e r v e them b o th on j 1 t h e colum n and i n t h e e l u t e . ! I | R e c o g n iz in g t h e d i f f i c u l t i e s d i s c u s s e d a b o v e , I c h r o m a to g r a p h ic a d s o r p t i o n o f p o ly m e r w as s t u d i e d by u s i n g : j 1 . A d s o r b e n t: A c t i v a t e d c h a r c o a l and c e l i t e m i x t u r e . I 2 . P o ly m e r: P o l y s t y r e n e f r a c t i o n s . j 3 . S o l v e n t s : M e th y l e t h y l k e to n e (p o o r s o l v e n t ) T o lu e n e ( b e t t e r s o l v e n t ) j T e t r a l i n ( b e s t s o l v e n t ) S a m p le s o l u t i o n s o f know n c o m p o s i t i o n s w h ic h w e r e m ade b y m ix in g t h e p o l y s t y r e n e f r a c t i o n s o f know n m o l e c u l a r w e i g h t s w e r e u s e d . A n a l y s i s o f t h e f r a c t i o n s w e r e c a r r i e d o u t v i s c o m e t r i c a l l y . I t w a s fo u n d t h a t a p o o r s o l v e n t , m e t h y l e t h y l k e t o n e c o u l d n o t J e l u t e t h e p o l y s t y r e n e o u t o f t h e c o lu m n ; t h e b e t t e r j s o l v e n t , t o l u e n e o n l y e l u t e d o u t a s m a l l p o r t i o n o f ! lo w m o l e c u l a r w e i g h t p o l y s t y r e n e , w h e r e a s t h e b e s t j j s o l v e n t , t e t r a l i n e l u t e d m o st o f t h e p o l y s t y r e n e ! ! | I o u t o f t h e c o lu m n . ! i ! I I I . B a s e d o n t h e o b s e r v a t i o n o b t a i n e d a b o v e , s t e p w i s e i i | e l u t i o n w i t h t h r e e s o l v e n t s w a s p e r f o r m e d . T he I 1 ! r e s u l t s sh o w ed t h a t a s m a l l p o r t i o n o f p o l y s t y r e n e ! | w i t h m o l e c u l a r w e i g h t o f t h e o r d e r o f IQ1 * w a s I ] e l u t e d o u t b y t o l u e n e a n d m o st o f t h e p o l y s t y r e n e | | w i t h t h e m o l e c u l a r w e i g h t o f t h e o r d e r o f 1 0 ^ w a s I ; ! e l u t e d b y t e t r a l i n . T h is i s c o n s i s t e n t w i t h th e j j ■ j j o b s e r v a t i o n s d e s c r i b e d i n I I . . F u r t h e r m o r e , t h e j i j p o l y s t y r e n e w a s e l u t e d o u t i n t h e o r d e r o f i n c r e a s - j I i n g m o l e c u l a r w e i g h t o f t h e p o l y s t y r e n e . T he e x p l a n a t i o n s f o r t h e s e o b s e r v a t i o n s b a s e d o n t h e j j i n f o r m a t i o n fr o m t h e a d s o r p t i o n i s o t h e r m s o f p o l y - i ! s t y r e n e - c a r b o n - m e t h y l e t h y l k e t o n e s y s t e m and p o l y - i s t y r e n e - c a r b o n - t o l u e n e s y s t e m a s w e l l a s fr o m t h e t I __________ p o i n t o f v ie w o f t h e s o l u b i l i t y o f t h e p o ly m e r w e r e j d i s c u s s e d . I n o r d e r t o im p r o v e t h e e f f e c t i v e n e s s o f t h e s e p a r a t i o n o f p o l y s t y r e n e , m ix e d s o l v e n t s w e r e u s e d f o r e l u t i o n . T h e c o lu m n o n w h ic h t h e p o l y s t y r e n e m ix t u r e w a s d e p o s i t e d fr o m p o o r s o l v e n t w e r e e l u t e d w i t h s o l v e n t m i x t u r e s a r r a n g e d i n s u c h a w ay a s t h e s o l v e n t s i n c r e a s e e l u t i n g p o w e r . T he r e s u l t s sh o w ed t h a t t h e s e p a r a t i o n w a s m ore s a t i s f a c t o r y t h a n t h e p r o c e d u r e d e s c r i b e d i n I I I . T h is f a c t I I s u g g e s t s t h a t c h r o m a t o g r a p h ic a d s o r p t i o n t e c h n i q u e j may b e u s e d a s p r e p a r a t o r y m e th o d f o r t h e f r a e t i o n a t i t i o n o f p o l y s t y r e n e b y u s i n g a l a r g e r c o lu m n and i i am ou n t o f s a m p le . j An a t t e m p t t o c a r r y o u t t h e p a r t i t i o n c o lu m n j i c h r o m a to g r a p h y o f p o l y s t y r e n e f a i l e d ; b e c a u s e n o j p a i r o f i m m i s i b l e s o l v e n t s i n w h ic h p o l y s t y r e n e i s s o l u b l e c o u ld b e f o u n d a f t e r e x t e n s i v e t e s t s . i One p o s s i b l e w a y o f d e t e r m i n i n g t h e v i s c o s i t y - a v e r a g e m o l e c u l a r w e i g h t o f t h e p o ly m e r s o l u t i o n s w h o s e c o n c e n t r a t i o n i s n o t know n w a s p r o p o s e d . 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Creator Yeh, Si Jung (author)

Core Title Method and technique in chromatographic separation of high polymers

Degree Master of Science

Degree Program Chemistry

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag chemistry, analytical,OAI-PMH Harvest

Language English

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Permanent Link (DOI) https://doi.org/10.25549/usctheses-c17-793968

Unique identifier UC11347696

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Legacy Identifier EP41614.pdf

Dmrecord 793968

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Rights Yeh, Si Jung

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Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

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