Copolymerization of Styrene and Acrylonitrile Initiated by the Redox Reduction of Hydroperoxide...

8/13/2019 Copolymerization of Styrene and Acrylonitrile Initiated by the Redox Reduction of Hydroperoxide Grafted to the S

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818 A .V . DMITRENKOet al.15 . V . A . B E R S H T E I N a nd V . M . Y E G O R O V , V y s okom ol . soye d . ,4 ,27 : 2440 , 1985 ( T r a ns l a t e din Polymer Sc i . U .S .S .R . 27 : 11 , 2743, 1985)

1 6 . G . V . G U S A K O V A , G . S . D E N I S O V a n d A . L . S M O L Y A N S K I I , Z h u rn . p r i k l , s p e k tr o s k o p ii ,16: 320; 502, 19721 7. G . V . G U S A K O V A , G . S . D E N I S O V a n d A . L . S M O L Y A N S K H , T e o r e t . i e k s p e ri m , k h i m i y a9: 387, 19731 8. G . S . D E N I S O V , G . V . G U S A K O V A a n d A . L . S M O L Y A N S K Y , J . M o l e c , S t ru c t. 1 5 : 3 77 ,

19731 9. G . S . D E N I S O V a n d V . M . S H R A I B E R , D o k l . A N S S S R 2 1 5 : 8 41 , 1 97 420. A . I . K U L ' B I D A a n d V . M . S H R A I B E R , D o k l . A N S S S R 2 5 0 : 8 8 9 , 1 9 8 02 1 . G . S . D E N I S O V , A . I . K U L ' B I D A , Z . Z , R E C H A P O V , A . L . S M O L Y A N S K I I a n d V . M .

S H R A I B E R , K h i m . f iz i ka 1 : 221 , 198222. G . V . G U S A K O V A G . S . D E N I S O V a n d A . L . S M O L Y A N S K I I , K h i m . f i z i ka 4 : 5 3 4, 1 9 8 523 . A . I . K U L ' B I D A , K h i m . f i zi ka 1 : 802 , 19822 4. N . S . K A R D A S H , V . A . K R O N G A N Z , V . L . Z A I T S E V a n d A . B . M O V S H O V I C H , V y s o k o -

mol . soyed . AI6: 390 , 1974 (Trans la ted in Polymer Sc i . U .S .S .R . 16 : 2 , 453 , 1974)

PolymerScienceU.S .S .R . V o l . 3 0 No . 4 pp . 818-826, 1988Printed in Poland 0032-3950/88 $10.00+.001989 Pergamon Pr os pie

C O P O L Y M E R I Z A T I O N O F S T Y R E N E A N DA C R Y L O N I T R I L E I N I T I A T E D B Y T H E R E D O X

R E D U C T I O N O F H Y D R O P E R O X I D E G R A F T E D T OT H E S U R F A C E O F D I S P E R S E D F IL L E R S

A . V . D M I T R E NK O , S . S . IV A N C H E V, V . A . D E M ID O V A a n d S . L . M O S K O V S KI IP l a s t o l p o l i m e r S c i en t if ic P r o d u c t i o n A s s o c i a t i o n , O k h t i n s k

Received 31 October 1986)T h e e o p o l y m e r i z a t i o n o f s t y re n e a n d a c r y l o n i t r i l e n i t i a t e d b y r e d o x d e g r a d a t i o n o f h y d r o -

pe r ox i de g r a f t e d t o t he s u r f a c e s o f d i s pe r s e d f il l er s o f va r i ous s t r uc t u r e a nd c on t a i n i n g s i l ic ond i ox i de i$ s tud i e d . I t i s e s t a b l i s he d t ha t c oa t i ng o f t he f i l l e r pa r t i c l e s w i t h a g r a f t e d l a ye r o f c on -s i de r a b l e t h i c kne s s r e s u l ts i n t he a ppe a r a nc e o f a ge l e f fe c t e ve n du r i ng t he r e a c t i o n s t a ge. T hep r e s e nc e o f a g r a f t e d s u r f a c e a nd a g r a f t e d c a p i l l a r y s y st e m on t he m i c r o f i b r i l l a r f i ll e r S i vo l ,i n c o n t r a s t t o A e r o s i l , r e s u l t s in a s i gn i f ic a n t de c r e a s e i n e f f e c ti ve nes s o f po l ym e r i z a t i on i n i t i a -t i on , a nd a l s o a c e r t a i n e n r i c hm e n t o f t he g r a f te d c opo l y m e r by the a c r y l on i t r i l e un i t s . T he e f -f ec t iv e c o p o l y m e r i z a t i o n c o n s t a n t s a r e d e t e r m i n e d . A m a t h e m a t i c a l m e t h o d o f c a lc u l a t in g t h ei n i t i a t i o n e ff e ct ive ne ss a nd t he e f f ec t ive de g r a da t i on c ons t a n t o f t he g r a f t e d h yd r o pe r ox i de a sd e t e r m i n e d f r o m r a d i c a l f o r m a t i o n d a t a i s p r o p o s e d .

O F t h e m e t h o d s o f l o c a l i z in g p o l y m e r i z a t i o n i n t h e s u r f a c e z o n e o f t h e d i s p e r s e p h a s eu s e d i n t h e p r o d u c t i o n o f c o m p o s i t e m a t e r i a l s b y t h e p o l y m e r i z e d fi lm m e t h o d , t h eu s e o f a f il le r w i t h p e r o x i d e g r o u p s c h e m i c a l l y g r a f t e d t o i ts s u r f a c e i s p r o m i s i n ~ [1 , p .

* V}tsokom01. so~'ed. A30 N o. 4, 807- 81 3, ~[98~,


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C opo l ym er i za t i on o f s t y rene and ac ry l on it r il e 8 92 1 6] . T h i s a p p r o a c h p r o v i d e s a m e a n s , e v e n w i t h o u t t h e f il le r m o d i f i c a t io n s ta g e , o fp r e d i c t in g t h e g r a f t in g d e n s i ty , a n d th e m a c r o m o l e c u l e c h a r a c te r is t ic s , a n d t h e c o r r e -s p o n d i n g p r o p e r t i e s o f t h e c o m p o s i t i o n s . T h e u s e o f in i t ia to r -f i l le r s w h i c h g e n e r a t ee x c lu s iv e ly g r a f t e d r a d i c a l s, a n d w h i c h e n s u r e i n it ia t io n o n l y b y g r a f t p o l y m e r i z a t i o n[ 1 , 2 ] is o f s p e c i a l i n t e r e s t .

I n t h is w o r k t h e s p e c ia l f e a t u re s o f g r a f t c o p o l y m e r i z a t i o n o f s t y re n e w i t h a c r y l o -n i tr i le a n d t h e e f fe c t o n t h e f il le r s tr u c t u r e o n t h e p r o c e s s is s tu d i e d , w i t h d u e a l l o w a n c ef o r th e p r e v i o u s l y d i s c o v e r e d l a w s g o v e r n i n g t h e g r a f t p o l y m e r i z a t i o n o f s t y re n e i n it i-a t e d b y r e d o x d e c o m p o s i t i o n o f g r a f t e d h y d r o p e r o x i d e ( G H P ) o n a n A e r o s i l s u r f a c e [2 ].

Si l icon diox ide c on tain ing tw o types o f f il lers was used, i .e. f inely dispersed grains A-175 Ae rosi lof specific surfac e S,p= 175 m 2 an d the micro fibri l lar ma terial , Sivol. of specific surfac e Ssp =47 0m~/g (where S ,p was measured by the BET method) .

S ivol cons i s t s of f ibr i l s ob ta ined f rom surfaces wound in to tubes , forming hol low capi l l a r i es ofd iam eter 10-50 A (Fig . 1 ). Th e Aeros i l and Sivol wi th graf ted G H P w ere obta ined in a two-s t age me-thod by t rea tm ent of t he f il le r t r i ch loron orbo rnen yl s i l ane (TCN S), and i ts subsequent ozoniza t ion

G m f t v d p o ly m e p

FIG . 1 . E l ec t ron m i c rog raph o f an e l em en t a ry S i vo l f ib re w i th a s t y ren e -A N copo l ym ergraf t ed to the surface (mag ni f i ca tion 220 x 103) and d iagra m show ing the d i s t r ibu t ion of

graf t ed p olym er a long the f ibre c ross-sec tion .

[4] . A cco rd i ng t o l vanch ev et aL [4] TCNS can be graf t ed f rom boi l ing so lu t ion in to luene (concen-t ra t ion 0 .06 mole / l . ) in the p resence of 0.07 wt . % K O H , w i th subsequent v acu um di s t il la t ion o f theso lvent and excess TCNS. Af ter washing the f i l l e r wi th methanol i t was ozonized in methanol .

The ex ten t of f il le r mod i f i ca tion was de termined by IR sp ec t roscopy. Du r ing po lyme r iza t ion af il le r con ta in ing (7-8) x 10-5 m ole /g was used . Th e s tyrene and acry loni t r i l e (A N) w ere eopo lymer izediO D M F A so l u t ion a t a t o t a l m ono m gr con cen t r a t i on o f .5 .5 m o l e / g (G H P concen t r a t ion 5 0 10 -~


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820 A. V. DMrrRI~NKO t am o l e / L 5 0 - 7 0 C ) , o v e r 0 .5 h r w i t h v a r i a ti o n o f t h e A N c o n t e n t o f t h e m o n o m e r m i x t u re fr o m 1 0 t o9 0 m o l e ~ o. A r e v e r s i b le F e I I I) s t e a r a t e - b e n z o i n sy s t e m w a s u s e d a s r e d u c i n g a g en t . F o r c o m p a r i s o nt h e r e d u c t i o n w a s c o n d u c t e d i n t h e p r e s e n c e o f m o d i f i e d f il le r s , a n d a l s o u n d e r h o m o g e n e o u s c o n d i -t i o n s w i t h i n i t i a t i o n b y b e n z o y l p e r o x id e 5 .8 1 0 - ~ m o l e / l .) . T h e g ra ft ed a n d u n g r a ft e d p o l y m e r sw e r e a n a l y z e d s i m i l a r l y [ 5] . T h e f r e e r a d i c a l y i e l d w a s d e t e r m i n e d b y t h e B a g d a s a r y a n m e t h o d [ 6, p .3 4 ] w i t h t h e a i d o f t h e f r e e ra d i c a l , 2 ,2 , 6 , 6 -t e t r a m e t h y l - 4 - h y d r o x y p y r i d i n e - l - o x id e . T h e m o r p h o l o g yo f t h e g ra ft ed p o l y m e r w a s s t u d i e d u n d e r a t y p e E A - 1 0 0 . L e l e c t r o n m i c r o s c o p e .

In t h e g i v en s y s tem t h e p r i m ary r ad i ca l s a r e g en e ra t ed b y t h e r eac t i o n o f p e ro x id ew i t h t h e d i v a l en t Fe c o m p o u n d fo rm ed o n t h e r ed u c t i o n o f Fe ( I I I ) s t ea r a t e b y b en zo i n,i n a c c o r d a n c e w it h t h e s c h e m e

l;e (~t),~-}-L ~ l t , F e ( St,) ~ + E H '~ - - R O O H + F e 0 1 ) - - - ~ - - R O ' + O H - + F e (] II ),

w here S t = C H , ( C H 2 ) , 0 C ( O ) 0 - ; E H = C 6 H s C H ( O H ) C ( 0 ) C olt.~;EII'--zC~II~C(O)C(O)C6H~; ROO H: _ ~S i-- -- -~ tOI_Ctt--OOII-- ./OCH3

Th e rad ica l s , which a re a lm os t a l l f ixed on the so l id po ly m er su r face , in i t ia t e theg ra f t p o l y m er i za t i o n o f mo n o m ers , i .e .

~ - - R O ' + n M I - I - m M 2 -~ ~ - - RO [M I]a [M2}6 ~ -+- [M1]~ ,a IM ply 0H o w ev e r , f o rm a t i o n o f a ce r t a i n q u an t i t y o f u n g ra f t ed p ro d u c t is a l so o b s e rv ed

t o g e t h e r w i t h t h e g r a f t ed co p o l y mer . T h i s i s b ecau s e t h e rm a l p o l y mer i za t i o n mak es as ig n if ican t co n t r i b u t i o n i n t h e co p o l y me r i za t io n o f s t y r en e w i t h A N o v e r th e g i v entempera tu re range . Thus , i t i s es t ab l i shed tha t in the p resence o f modi f i ed f i l l e r s ther a t e o f co p o l y m er i za t io n o f t h e s e m o n o m ers a t 7 0C i s 2 -3 ~o/h r. I n t ro d u c t i o n o f t h eFe ( I I I ) -b en zo i n s y s t em in t o t h e r eac t i o n m i x t u re s o me w h a t d ec rea se s th e t h e rma lpo lymer iza t ion ra t e , which i s never the less abou t 1%/hr .

T h e y i e l d o f g r a f t ed p o l y mer fo rmed o n i n i t i a t i o n w i t h A ero s i l s u r f ace (F i g . 2 a )i n c rea se s b o t h w i t h r is e i n t em p era t u re an d w i t h i n c r ea s e i n r eac t i o n t i me . T h e g ra f t edp ro d u c t f o rm ed h as a h i g h M M , t h e v a lu e o f w h i ch is d i rec t l y r e l a t ed t o t h e r eac t i o nt ime , a n d a t t a i n s a v a l u e o f ab o u t l0 6. A t a ce r t a i n d eg ree o f co n v e r s i o n (7 -8 ~ ) t h e r eis a rap id increase in ra t e , which i s m ore no t i ceab le a t 70C (Fig . 2b). Acce lera t ion o ft h e r eac t i o n is a cco m p an i ed b y i n c rea s e in t h e M M o f t h e g r a f t ed co p o l y me r (F ig . 2 b ).

The above f ind ing i s as soc ia ted wi th the ge l e f fec t , due to the p resence o f a h igh lyd ev e l o p ed p h as e i n t e r f ace in t h e s y s tem. I t c an b e a s s u m ed t h a t f o rm a t i o n o f a g r a f t edp o l y mer , u n i fo rml y d is t r ib u t ed o v e r t h e d i s p e r se p h as e s u r f ace p ro mo t es , a s t h e g r a f t edl ay e r g ro w s , p h y s i ca l h o o k i n g o f an d o v e r l ap p i n g o f t h e l ay e r s ad j acen t t o s p ec i f i cpar t s o f the f i l l e r , and the fo rmat ion o f a pseudo-s t ruc tu red sys tem, wi th consequen t


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Copolymerization of Styrene and ac rylon itr i le 8 2r e s tr ic t io n o f t h e te r m i n a t i o n r e a c t i o n . D u r i n g h e t e r o p h a s e p o l y m e r i z a t i o n t h e r e a o t io nm a s s t h ic k e n s m u c h m o r e r a p id l y , a n d e v e n a t a c o n v e r s i o n o f o n l y 7 - 1 0 ~o h a s a l m o s tc o m p l e te l y l o st i ts m o b i l it y , T h e m i n i m u m c o n t e n t o f g r a ft e d p o l y m e r r e q u i r e d f o r

v a 9 /g LF o /0 8 - / . / ~

o. 5 _ _

I I I I2 q 8 8u,*/./hr ~ M? IO

/ j / - oo-2oo

2 4 G 8 :Time , h ,Fio. 2 . Copolym er yie ld (a), an d also ~ '~ (1, 2) and the overall process rate fb) as a func t ionof process time: 1 - 4 , 1 ' 2 - in the presence of Aerosi l; 5,5' , 6- i n the presence of Sivol;o / o1,2,5-grafted, l',2 ,S-tmgrafted copolymer; 1, 1 ,3 -5 0 C, 2 ,2 ,4 ,5 ,5 ,6 -70 C , D M F A ;[MI + M 2]=5 .5 mole/l .; [ fi ll er ]=65 g/ I . ; [G H P] =5 .0x 10-3; [benzoin]= 1.65 x 10-3;[Fe stearate] = 3.8 x 10 -4 m ol e/ l .

e s ta b l is h i n g s u c h a t h r e e - d i m e n s i o n a l n e t w o r k a n d t h e a p p e a r a n c e o f th e g e l e f fe c t,a s j u d g e d f r o m F ig . 2 , is a b o u t 3 x 1 0 - 3 / m 2 i n t h e c a s e o f A e r o s il .

I t c a n b e a s s u m e d t h a t t h e g e l e f f e c t w i ll b e s i g n if ic a n t i n th e c a s e o f S i v o l, w h i c hh a s a m o r e d e v e l o p e d s u r f a c e t h a n - A e r o s i l . H o w e v e r , i t i s f o u n d t h a t o n i n i t i a t i o n o fs t y r e n e c o p o l y m e r i z a t i o n w i t h A N u s i n g a S iv o l, s u r f a c e ( a t th e s a m e s u r f a c e c o n c e n -t r a t i o n o f G H P ) t h e g el e f fe c t d o e s n o t o c c u r . O n t h e o t h e r h a n d , t h e r e a c t i o n r a t e is l o wa n d g r a d u a l l y d e c r e a s e s d u r i n g t h e r e a c t i o n ( F i g . 2 a ) . O n e r e a s o n f o r t h i s d i f f e r e n c ec o m p a r e d w i t h a s y s t e m f il le d w i t h A e r o s i l c o u l d b e t h e l o w r a t e o f i n i ti a t io n .


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8 2 2 A . V . D M I T R E N K O e t e lT o e x p l a in t h i s p r o b l e m , t h e y i e l d o f fr e e r a d ic a l s o n p o l y m e r i z a t i o n i n it ia t io n

o f G H P w i th A e r o s i l a n d S iv o l s u r fa c e s w a s c o m p a r e d , u s i n g t h e p o l y m e r i z a t io no f s t y r e n e i n c h l o r o b e n z e n e s o l u t i o n a s a n e x a m p l e . I t is o b s e r v e d ( F ig . 3 ) t h a t t h e f r e e

[ R o : ] 1 o ~ o l e / t . [ R o ' . l. lO o Z e / t .10 ~ - 10

- - e

Z100 200 300Time rain

FIG. 3

, CROl.- l n ( 1 - '~ o 3 - = ~1 6

0 8

8 tO -J, se cFIG. 4

/

1x Z

116

FIG. 3. Yield of prim ary radicals as a function o f t im e at 70C, 1 - in i t ia t io n with an Aerosil surface,[RO OH ]o=0.5 x 10-2; 2- in i t ia t io n wi th a S ivol surface , [RO OH ]o=0.46 x 10 -z . [FeSt3]=3 .8 xx 10 -* mol/l. ; [b enz oin= 1.65 x 10 -3 mole/1.l n~ l [RO' I ~FIG . 4. - \ - [--R--6~-]]as a fm~tion of t ime. G H P on Aerosi l (1) and Sivol (2); IROOH ]o 10z

=0.5 (1) and 0.46 mote/1. (2) .r a d i c a l y i e l d w i t h t h e S i v o l s u r f a c e i s s i g n i f i c a n t l y l o w e r t h a n w i t h t h e A e r o s i l s u r f a c ef o r t h e sa m e G H P c o n c e n t r a t io n .

I t i s i n t e r e s t i n g t o c a l c u l a t e t h e v a l u e o f t h e i n i t i a t io n e f f ic i e n c y i n t h e g i v e n s y s t e m s .H o w e v e r , d e t e r m i n a t i o n o f th i s p a r a m e t e r b y t r a d i t i o n a l m e t h o d s i s d i ff ic u lt i n p r a c ti c e .I t is t h u s p r o p o s e d t o c a l c u l a t e f b y m a t h e m a t i c a l t r e a t m e n t o f th e r e su l t s g iv e n i n F ig . 4.T h e d i f f e r e n t i a l e q u a t i o n d e s c r i b i n g t h e i n i t i a t o r d e g r a d a t i o n i s

d [ R O O H ] / d t = - k [ F e S t 2 ] [ R O O H ] (1 )a n d c a n b e s o l v e d f o r t h e i n i ti a l c o n d i t i o n

[ R O O H ] = [ R O O H ] 0 a t t = 0 2 )( w h e r e [ R O O H ] is th e i n it ia l i n i ti a t o r c o n c e n t r a t i o n a n d k is th e e f f e c ti v e d e g r a d a t i o nr a t e c o n s t a n t ) .

T h e a c t u a l y i e l d o f p r i m a r y r a d i c a ls i s d e s c r i b e d b y t h e e q u a t i o nd [ R O ' ] / d t = f k [ Fe S t2 ] [ R O O H ]

f o r t h e in i ti al c o n d i t io r t s [ R O ' ] = 0 , t = 0 ,


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(2)

~x)polym et izatiOtio f styr en e arid act ylonitrile 8~):~T h e s o l u t i o n o f th e gi v e B e q u a t i o n i s

[ R O ] t ) = f k ~ [ R O O H ] t ) d roT h e f u n c t i o n [ R O ] ( t ) i s d e t e r m i n e d b y s o l u t i o n o f ( 1 ) u n d e r t h e i n it ia l c o n d i t io n s

an d o n a l l o wi n g fo r t h i s[ R O O H ] = [ R O O H ] o e xp - k ' ,

[ R O ' ] =fk [ R O O H ] o ~ exp-k dtoOn in teg ra t ing i t i s found tha t [RO ]=f[ROO H]o(l-exp-kt) .Th e l a s t eq u a t i o n s h o ws th a t t h e co n cen t r a t i o n o f p r i m ary r ad ica l s t en d s to t h e

l im i t in g v a l u e [ R O ' ] = f [ R O O H ] o , a t t -~ o f r o m w h ic h it is p o s s ib l e t o fi nd fI f th i s re la t ion i s g iven in the fo rm

l n ( 1 [ R O ] ~[ - ~ j : k t ,o n t r ea t in g t h is (F i g 4 ) a t a k n o w n v a l u e o f f i t is p o s s i b l e t o d e t e rm i n e t h e v a l u e o f k ,

W h e n f = 0 . 2 6 , o n i n it ia t io n w i th a n A e r o s i l s u r fa c e a n d f = 0 . 0 2 o n i n i ti a ti o n w i t ha S ivo l su r face ( these va lues g ive the best ap p ro x i m a t i o n t o t h e ex p e r i m en t a l cu rv e ) ,t h e v a lu e k : l . 1 x 10 - 4 s e c - 1 w a s o b t a in e d

Th e reaso n fo r such a sh arp fa ll in the e f fec t iveness o f in it i a tion w hen the hyd ro-peroxide g ro u p s a r e f i xed o n t h e S i v o l s u r f ace t o a l l ap p ea ran ces m u s t b e s o u g h t i n thes t ru c t u ra l f ea t u re s o f t h e g i v en fille r. I t c an b e a s s u m ed t h a t t h e f i xa t io n o f G P H t ak esp l ace o v e r t h e wh o l e s u r f ace o f t h e m i c ro f ib re , in c l ud i n g t h e i n te rn a l s u r f aces o f t h ecap il la r ie s . Th e c l o s en es s o f t h e ad j acen t G H P, wh i ch is d e t e rm i n ed b y th e u n fav o u rab l erad ius o f cu rv a tu re o f the cap i l l a r ies can , in the au th ors ' op in ion , resu l t in increasedp ro b ab i l i t y o f r eco m b i n a t i o n o f t h e p r i m ary r ad i ca l s an d ch a i n t e rm i n a t io n a t th e s eradicals .

As a r e s u l t o f the decre ase in ef fi ciency o f po lyme r iza t ion in i t ia t ion the g row tho f t h e g ra f t ed l ay e r a t p a r t s o f t h e S i v ol i s h i n d e red an d d o es n o t ex ceed ( a s can b e s eenfrom Fig . 2 ) 0 .25-0 .3 g pe r 1 g o f f ill er , w h ich am oun ts to a bou t 1 .8 x 1 0- a g /m 2 , w hichis a lm os t h a l f the va lue fo r the po ly m er coa t ing o f Ae ros i l par t i c les in which a ge l e f fec tap p ea r s . P ro b ab l y t h is am o u n t is in s u ff ic i en t fo r co a t i n g o f t h e f i b re s u r f aces an d fo rm a i n t a i n in g t h e ir d eg ree o f d i s p e r s i o n d u ri n g t h e p ro ces s an d fo r t h e fo rm a t i o n o fp s eu d o - s t ru c t u red s y s t em s .

I t i s i n t e re s t in g t o s h o w t h e e f f ec t o f s u r f ace m o d i f ica t i o n b y h y d ro p e ro x i d e g ro u p so n t h e r e l a t i v e r eac t i v i t y o f m o n o m ers , w i t h d u e a l l o wan ce fo r p rev i o u s s t u d i e s o n t h eco p o l y m er i za t i o n o f s ty ren e an d A N o n A ero s i l an d S i v o l w i t h n a t u ra l = S i OH an dmethy l methacry la te func t iona l coa t ings [5 ] .


7/9

~ 4 A . V . ] [) M IT I~ I~ N K O e t a tTABL E 1. YIELD AND COMPOSITION OF A COPOLYMER AS A FU NCTION OF THE COPOLYMERIZATION CON D|-

TIONS OF AN AZEOTROPIC MIXTURE OF STYRENE AND A N IN THE PRESENCE OF FILLER( D M F A , [ s t y r e n e + A N ] = 5 . 5 m o l e / l . , [ F e s t e a r a te ] = 4 . 2 1 0 - 4 m o l e / l , [ b e n z o i n ] = l . 6 5 x 10 - a

T e s tN o .

2 *3456789

F i l l e r

A e r o s i l

S i v o l

[ G H P , u r] xx 10 3,

m o l e / l .T

I 01 112131 4151 61 7

m o l e / l . )

C o n v e r -T i m e , s i o n , .h rA N c o n t e n t o f c op o l y m e r ,

m o l e ~g r a f t e d

c o p o l y m e r000 ' 0 80 ' 0 80 ' 0 80 . 0 80 ' 0 80 ' 0 80 ' 0 8000 . 0 70 . 0 70 0 70 ' 0 700

7 07 05 05 05 07 07 07 07 07 07 07 07 07 07 07 07 0

0 . 540 . 5248 '0 ' 54

2 7 62 7 2

4 ' 510 520 7

8 98 ' 8

11 63 8 . 0

5 ' 24 5 - 0

3 ' 85 .26-88-75 02 7 6

2 9 ' 83 6 ' 73 6 . 734-334 33 6 ' 73 5 . 9

4 5 ' 9 1 . 30

4 5 ' 9 + _ 1 . 34 4 ' 1 l . 34 5 4 + _ 1 . 345~ 4 +_1 3

00

u n g r a f t e dc o p o l y m e r

3 5 '13 6 . 72 8 . 83 6 . 73 6 ' 736 73 4 . 0

m34 0

42 .6 +_ 1 44 1 ' 4 + _ 1 . 34 5 . 2 + _ 1 . 444 .5 : [: 1 445 -7 +_ 1 445 4~_ 1 . 437 .8 ~ 1 237 .8 +_ 1 2

Benzoyl l~roxide concentr ation 5.8 x 10 -a mole/I.Note In te~ts 1-9 the composition of the copolymers was determined fro m elemental analysis, and in tests 10-17 from p yro-

lytic chromatography da ta.

TABLE 2 . C O P O L Y M E R I Z A T I O N C O N S T A N T S O F A N r l ) A N D S T Y RE N E ( r 2 ) I N H O M O G E N E O U S A N D H E T E R O -G E N E O U S P R O C E S S E S

( D M F A , 7 0 C , [ b e n z o y l p e r o x i d e ] = 5. 8 x 1 0 - a m o l e / l . , [ G H P ] = ~ .0 x 1 0 - a m o l e / I . , [ s ty r e n e + A N ]= 5 . 5 m o l e / l . )

r t I r 2 I r l F 2 r l [ r 2 [ F I r 2F i l le r a s c a l c u l a te d f r o m t h e a s c a l c u l a te d f r o m t h e

F i n e m a n - R o s e e q u a t io n K e l e n - T y d o s h e q u a t io n- - * 0 . 0 2 3 + _ 0 0 1 0 0 8 31 + _ 0 2 60

U n m o d i f i e d S i -v o l * 0 . 0 2 6 + _ 0 . 0 0 5 0 . 6 3 6 + _ 0 . 1 2 0

S i vo l w i th G H P g r a f t e d c o -p o l y m er ) 0 . 0 4 3 +_ 0 . 0 0 3 0 . 5 8 0 _+ 0 . 0 6 0

0 ' 01 9 I 0 + 0 ' 0 3 00 ' 01 7 0 + 0 0 2 0

0 ' 0 2 4 0 . 0 3 6 + _ 0 . 0 1 1* B e n z o y l p e r o x i d e f il le r .

0.63 1 +_0-070 00-552 +_ 0 .06 0 0

0 . 5 5 4 + _ 0 . 0 4 0 I 0 ' 0 1 9

A s c a n b e s e e n f r o m t h e d a t a i n T a b l e I , t h e p r e s e n c e o f A e r o s i l w i t h G H P i n t h er e a c t i o n z o n e h a s h a r d l y a n y e f f e c t o n t h e c h a n g e s i n c o m p o s i t i o n o f t h e g r a f t e d c o -p o l y m e r c o m p a r e d w i t h t h e u n f i l l e d c o p o l y m e r , t h e f o r m a t i o n o f w h i c h w a s i n i t i a t e d


8/9

Copolymerlzatlonof styrene and acrylonitrileby benzoyl peroxide. When Sivol and GHP are in the reaction zone, grafted and un-grafted copolymers are formed only slightly enriched with AN (Table 1, Fig. 5). Theintroduction of a mixture of unmodified Sivol with a silane surface coating into the

m mo le

60

20 ~ 220 60 I00N, ole

FIG. 5. Compositionof ungrafted (1, 2) and grafted copolymer 3) as a function of the com-position of the monomericmixture(M t denotesacrylonitrile):1 - under homogeneouscondi-tions; 2 - in the presence of tmmodified$ivol; 3- in the presence of $ivol with grafted hydro-peroxide groups. DMFA, [ t + M2]=5 5, mole/l, 70C.

reaction mixture gives approximately the same results. In our view, the reasons for theobserved disturbance of copolymer composition must be a redis tribution of local con-centrations o f AN in the monomer mixture when there is a developed capillary systemin the filler.

To confirm this assumption, copolymers formed in the bulk of a heterogeneoussystem and directly in Sivol capillaries were compared. The tests showed that on initia-tion by free benzoyl peroxide, the copolymer formed in the capillaries is about 3 ~oenriched in AN, in contrast to the copolymer formed on initiation by free benzoylperoxide. This, it can be assumed that functionalization of the filler surface by GHPhas little effect on the relative reactivity of the monomers, and a certain deviationin composition of the grafted copolymers is due to the s tructural features of the filler.Figure 1 indicates that polymerization takes place in certain internal regions of the fibre.As can be seen from the electron micrographs, a layer under the external surface of thefibre is formed together with the external grafted polymer layer.

Table 2 shows the values of the effective copolymerization constants for AN (rl)and styrene (r2), as calculated with a computer using two iinearization methods, i.e.with the aid of the Fineman-Ross and Kelen-Tydosh equations. It can be seen fromthe given data that rt and r2 as calculated from the composition of the grafted copoly-mer and the copolymer formed in the presence of unmodified Sivol differ somewhat


9/9

82~ P. ~E . |L~MENE~et at.f r o m t h e v a l u e s o f r l a n d r2 f o r a n u n f i l l e d s y s t e m : t h e r e is a c e r t a i n t e n d e n c y t o w a r d sa d e c r e a s e i n t h e r e l a t i v e a c t i v i t y o f s t y r e n e a n d a n i n c r e a s e i n t h e r e l a t i v e a c t i v i t y o f A N .

T h e r e s u l t s t h u s i n d i c a t e t h a t t h e s t r u c t u r a l f e a t u r e s o f t h e f i ll e r h a v e a s i g n i f ic a n te f f e ct o n t h e k i n e t i c s o f c o p o l y m e r i z a t i o n o f s t y r e n e a n d A N , a n d a l s o in t h e r e la t iv er e a c t iv i t y o f t h e c o m o n o m e r s , a s a r e s u l t o f r e d i s t r i b u t i o n o f th e i r l o ca l c o n c e n t r a t i o n si n th e s u r f a c e z o n e s o f t h e s o l i d p a r t i c l e s .

Translated by N. STANDENREFEREN ES

1 . S . S . I V A N C H E V , R a d i k a l n a y a p o l i m e r i z a t s iy a ( R a d i c a l P o l y m e r i z a ti o n ) . L e n i n g r a d , 1 9 8 52 . S . S . I V A N T S C H E V a n d A . W . D M I T R E N K O , P l a s t e u n d K a u t s c h u k B 3 2 : 3 1, 19 853 . V . P . P R Y A N I S H N I K O V , V . F . G U S Y N I N , A . F . S O R O K I N a n d K . L C H E P I Z H N Y , R u s si a n

Pa t . 579246, ByulL Izobre t . No. 41 , 80 , 19774 . S . S . I V A N C H E V , N . S . Y E N I K O L O P Y A N , B . V . P O L O Z O V , A . A . S Y R O V , O . N . P R I M A -C H E N K O a nd Z . N . P O L Y A K O V , R us s i a n P a t . 787411, B yu l l . I z ob r e t . N o . 46 , 97 , 1980 ; C u r r e n t

W e s t G e r m a n P a t . N o . 2852778 ; U . S . P a t . N o . 421914; F r e nc h P a t . N o . 7834134 ; a nd J a pa ne s ePa t . No. 1029500.

5 . S . S . I V A N C H E V , A . V . D M I T R E N K O , V . A . D E M I D O V A a n d N . Y e . S H A D R I N A , V y s o k o -tool . soyed . A2 8: 2095, 1 986 (Tran s la ted in P oly m er Sc i. U .S .S .R . 28 : 10 , 2327, 1986)6 . K h . S . B A G D A S A R Y A N , T e o r i y a r a d i k a l n o i p o l i m e r iz a t s ii ( T h e o r y o f R a d i c a l P o l y m e r i z a ti o n ) ,

M os c ow , 1966

Polym er ScienceU.S .S.R. Vo l. 30, No. 4 , p p. 826-834, 1988Printed in Poland 0032-3950/88 10.00+.00 1989 Pergamon Press plc

F E A T U R E S O F E M U L S I O N P O L Y M E R I Z A T I O NO F S T Y R E N E U S I N G S L IG H T L Y S O L U B L E

I N I T I A T O R S

P . Y E . [ L ' M E N E V , G . I . L I T V I N E N K O , V . A . K A M I N S K I I a nd 1 . A . G R I T S K O V AL . Y a . K a r p o v P h y s i c o c h e m i c a l R e s e a rc h I n s t i tu t e

M . V . L o m o n o s o v I n s t i t u t e o f F i n e C h e m i c a l T e c h n o l o g y , M o s c o wReceived 2 November 1986)

T he e m u l s i on po l y m e r i z a t i on o f s t y r e ne in t he p r e s e nc e o f s li gh t l y s o l ub l e in i t i a t o r s i ss t ud i e d . A r e l a t i on i s obs e r ve d be t w e e n t he p o l ym e r i z a t i on r a t e a nd t he i n i t i a t o r s o l ub i l i t yi n t h e a q u e o u s p h a s e. A m a t h e m a t i c a l m o d e l o f t h e p r o c e s s i s c o n s t r u c te d f o r d e t e r m i n i n gt he c onc e n t r a t i on o f t he l a t e x pa r ti c l e s f o r m e d i n t he s y s t e m . I t i s s how n t ha t t he m a i n c on t r i -b u t i o n t o p a r t ic l e f o r m a t i o n i s p r o v i d e d b y t h e r a d i c a l s a ri s in g o n d e c o m p o s i t io n o f t h e i n i -t i a t o r d i s s o l ve d in w a t e r .

* V y s ok om ol . s oye d . A 30 : N o . 4 , 814 - 820 , 1988 .

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Copolymerization of Styrene and Acrylonitrile Initiated by the Redox Reduction of Hydroperoxide...

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