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Synthesis and polymerization (copolymerization) of fluorinated styrenes—I. Copolymerization of fluorinated styrene and vinyl monomers
270
A . F . DOKUKII~'Aet al. REFERENCES
1. A. A. BERLIN, N. G. MATVEYEVA and A. I. SHERLE, Izv. Akad. Nauk SSR, Otd. khim. nauk, 2261, 1959 2. A. A. BERLIN, N. G. MATVEYEVA and A. I. SHERLE, Authors' certificate No. 126612, 7. 4. 1959 3. A. A. BERLIN, L. I. BOGUSLAVSKII, R. Kh. BURSHTEIN, N. G. MATVEYEVA, A. I. SHERLE and N. A. SHURMOVSKAYA, Dokl. Akad. Nauk SSSR 136: 1127, 1961 4. Yu. Sh. MASHKOVSKII, N. D. KOSTROVA and A. A. BERLIN, Vysokomol. soyed. 3: 1669, 1961 5. A. A. BERLIN, B. I. LIOGON'KII and V. P. PARINI, Vysokomol. soyed. 2: 683, 1960 6. T. KU~ERA, Paper at the Prague Conference on High-Molecular-Weight Compounds, 1957 7. A. EPSTEIN and B. C. WIDLY, J. Chem. Phys. 32: 324, 1960 8. A. A. BERLIN, L. G. CHERKASHINA and Ye. I. BALABANOV, Vysokomol. soyed. 3: 2, 1961 9. C. S. MARVEL, and I. H. ROSSWEILER, J. Amer. Chem. Soc. 89: 1197, 1958 10. W. J. MIDDLETON and E. L. LITTLE, J. Amer. Chem. Soc. 80: 2795, 1958 11. O. W. WEBSTER, W. MAHLER and R. E. BENSON, J. Org. Chem. 25: 1470, 1960 12. A. A. BERLIN and N. G. MATVEYEVA, Dokl. Akad. Nauk SSSR 140: 368, 1961 13. T. L. CAIRNS etal., J. Amer. Chem. Soe. 80: 2775, 1958, 14. J. F. STEMBACH and J. H. BURNS, J. Amer. Chem. Soc. 80: 1839, 1958 15. T. L. CAIRNS et al., J. Amer. Chem. Soc. 80: 2775, 1958
SYNTHESIS AND POLYMERIZATION (COPOLYMERIZATION) OF FLUORINATED STYRENESeI. COPOLYMERIZATION OF FLUORINATED STYRENE AND VINYL MONOMERS* A. F. DOKUKINA, YE. I. YEGOROVA, G. V. KAZENNIKOVA, M. M. KOTON, K. A. KOCHESHKOV, Z. A. SMIRNOVA ,and T. V. TALALAYEVA Institute of High-Molecular-Weight Compounds, U.S.S.R. Academy of Sciences {Received 11 April 1961)
OF THE substituted polystyrenes, the polymers with substituents in the vinyl
chain are of great interest with respect to their physicochemical properties. I t has b e e n discovered [1-3] t h a t poly-a,fl,fl-trifluorostyrene a n d its c o p o l y m e r s w i t h s t y r e n e o b t a i n e d b y t h e emulsion m e t h o d possess a high h e a t - s t a b i l i t y similar t o t h a t o f p o l y t e t r a f l u o r o e t h y l e n e a n d good dielectric properties, while a t t h e same t i m e being soluble in organic solvents. H o w e v e r , the a u t h o r s n o t e d [1, 2] t h a t t h e h o m o p o l y m e r s o f a,fl,fl-trifluorostyrene are brittle a n d t h e i r prep a r a t i o n is difficult because t h e p o l y m e r i z a t i o n is a c c o m p a n i e d b y intense dimerization of the monomer. * Vysokomol. soyed. 4: No. 6, 885-888, 1962.
Synthesis and polymerization of fluorinated styrenes
271
We have carried out experiments on the production of copolymers of a,fl,fltrifluorostyrene, o-, m-, and p-methyl-g,fl,fl-trifluorostyrenes, and a,fl-difluorofl-chlorostyrene with styrene, 2,5-dimethylstyrene, 2,5-difluorostyrene, and methyl methacrylate. T A B L E 1. P R O P E R T I E S
Monomer
a, fl, fl-trifluorostyrene o-methyl-~,fl,fl-trifluorostyrene m-methyl-a,fl,fl-trifluorostyrene p-methyl- ~, fl, fl-trifluorostyrene a, fl-difluoro-fl-ehlorostyrene 2,5-difluorostyrene
OF T H E MONOMERS
F content (%)
B.p. (°C) (mm)
20 ?~D
67-70 (75) 72 (60) 89-90 (70) 83-5 (65) 56-58 (10) 56 (30)
1"4770 1.4710 1.4694 1.4823 1.5179 (19) 1.4982
Found
Calculated
36"5 33.01 32.95 33.05
36.07 33.14 33.14 33-14
27.46 27.54
27.13
EXPERIMENTAL The monomers used for copolymerization were carefidly purified and fractionated at a reduced pressure (Table 1). The copolymerization was carried out in emulsion b y a method developed by us. A n emulsion consisting of water (80-85~) of the weight of the reaction mixture), a n emulsifier (sodium stearate or oleate--2"5% of the total mixture), a persulphate initiator (0.5%), a n d a pI-Lregulator was placed in a three-necked flask fitted with a funnel-shaped mechanical stirrer and a dropping funnel. The contents of the flask were first heated to 80-90 ° and then a mixture of monomers containing a second initiator--azoisobutyronitrile (0"5~o of the weight of the monomers)--was added to it at 60 ° after which the reaction mixture was stirred for a long time at 60 °. The emulsion was broken with a 3~o solution of sulphuric acid. The copolymer isolated was repeatedly washed with water and hot methyl alcohol, was repreeipitated, a n d was then dried at an elevated temperature in vacuum. The composition of the copolymers was determined from the fluorine content. Using the method described, we obtained 11 copolymers of a,B, fl-trifluoro-o-, -m-, a n d -p-methylstyrenes a n d a,fl, fl-halogen-substituted styrenes with styrene, 2,5-dimethylstyrene, 2,5-difluorostyrene, a n d methyl methacrytate (Table 2). All the products obtained were readily soluble in organic solvents for thermoplastic polymers, which made it posible for us to determine the characteristic viscosities (Table 2) of benzene solutions at 20 ° and the heat.stability of the copolymers b y the I F P method.
DISCUSSION OF THE RESULTS In the study of the copolymerization of styrenes fluorinated in the side-chain w i t h v i n y l m o n o m e r s i t w a s f o u n d t h a t , o f a l l t h e p a i r s o f m o n o m e r s t h a t we tested, the c o p o l y m e r i z a t i o n of a,fl,fl-trifluorostyrene w i t h 2 , 5 - d i m e t h y l s t y r e n e t o o k p l a c e m o s t r a p i d l y . I t c a n b e s e e n f r o m T a b l e 2 t h a t t h i s c o p o l y m e r is formed in 4 hours w i t h a 9 0 % c o n v e r s i o n at a c o n t e n t of ~,fl,fl-trifluorostyrene o f 50.54 m o l e s - % a n d h a s q u i t e a h i g h m o l e c u l a r w e i g h t ([~/] = 1.1). T h e c o p o l y -
A.F. I)OKUKII~Aet al.
272
TABLE 2. TIME OF COPOLYMERIZATION,YIELD OF COPOLYMERS,THEIR COMPOSITIONS AND CHARACTERISTICVISCOSITIES Time of experiment (hr)
Composition of the copolymer (moles-%)
Yield of copolymer
(%)
M1
[
Characteristic viscosity of benzene solutions of the copolymers at 20 °
Me
Copolymers of a,fl, fl-trifluorostyrene (M1) with styrene (Me) 8 7 8 8
]
74 70 60 40
/ / i
28.53 39"77 48"53 53*75
71"47 60"23 51"47 46"24
/
2.7 2"8 1"8 0"9
Copolymers of a,fl, fl-trifluorostyrene (M1) with 2,5-dimethylstyrene (MQ 4 4
90 50
] i
50"54 60"77
49.16 39"23
1.1 0"6
Copolymers of g,fl, fl-trifluorostyrene (M1) with methyl methacrylate (Ms) 6 11
[ J
-41
I I
43-29 I 153"88
56"71 46.12
0"4 0-2
Copolymers of m-mothyl-a,fl, fl-trifluorostyrene (M1) with styrene (Me) 2.5 I 40 ] 46.26 I 53.73 I 0-5 Copolymer of o-methyl-~,fl, fl-trifluorostyrene (M1) with styrene (M2) 33 I 11 t 50.41 I 49.59 I 0.5 Copolymer ofp-methyl-a,fl, fl-trifluorostyrene (M1) with styrene (Me) 7 I 55 46.97 53"03 2.0 7 / 64 36"77 63.23 1.4 20
Copolymer of a,fl-difluoro-fl-ehlorostyrene (M1) with styrene (Me) 1 30 I 16.00 j 84.00 I 0.05
Copolymer of ~,/~-difluoro-fl-ehlorostyrene (M1) with 2,5-difluorostyrene (Me) 20 I 14 I t I o.~ m e r i z a t i o n o f a,fl,fl-trifluorostyrene with s t y r e n e takes place more s l o w l y - - f o r a c o p o l y m e r containing 48.53 moles-% o f the fluorinated styrene, the yield is o n l y 6 0 % a f t e r 8 hours' copolymerization. On c o m p a r i n g the conversion a n d the characteristic viscosity of copolymers o f ~,fl,fl-trifluorostyrene o f different compositions (Table 2) it m u s t be n o t e d t h a t t h e i n t r o d u c t i o n of t h e fluorine-containing c o m p o n e n t reduces the yield o f c o p o l y m e r a n d its characteristic viscosity, and, consequently, its molecular weight. Thus, on increasing t h e c o n t e n t o f a,fl,fl-trifluorostyrene in the c o p o l y m e r f r o m 28.53 to 53.75 moles-~o, t h e characteristic viscosity falls f r o m 2.7 to 0.9, a n d the yield o f copolymers a t r o u g h l y the same p o l y m e r i z a t i o n t i m e diminishes f r o m 74 to 40~/o.
Synthesis and polymerization of fluorinated styrenes
273
The copolymerization of ~,fl,fl-trifluorostyrene with methyl methacrylate, in all probability, goes with more difficulty than that with styrene and 2,5dimethylstyrene. After 11 hours' copolymerization, the yield of copolymer with methyl methacrylate amounts to only 41~o at 53.88 moles-~/o of a,fl,fltrifluorostyrene. The copolymers of a,fl, fl-trifluorostyrene with methyl methacrylate possess a relatively low molecular weight--the characteristic viscosity is between 0.4 and 0.2. Iu studying the copolymerization of a,fl-difluoro-fl-chlorostyrene-styrene system, it was found that the replacement of one fl fluorine atom in the vinyl chain of a,fl,fl-trifluorostyrene by a chlorine atom markedly diminishes the capacity of the substituted styrene for copolymerization with styrene. After 20 hours, the eopolymer of a,fl-difluoro-fl-chlorostyrene with styrene is formed in a yield of only 30% and has a very low characteristic viscosity [~]=0.05, in spite of the fact that the content of substituted styrene in the eopolymer is only 16 moles-~/o. The introduction of a methyl group into the benzene nucleus of ~,fl,fl-trifluorostyrene also reduces the capacity of the monomer for copolymerization. o-, m-, and p-methyl-a,fl,fl-trifluorostyrenes copolymerize with styrene more slowly t h a n unsubstituted a,fl,fl-trifluorostyrene. The copolymerization of the o-methyl-a,fl,fl-trifluorostyrene-styrene system is particularly strongly retarded. After 33 hours' polymerization a polymer is obtained with a yield of only 11%, although it has a high polymerization coefficient ([~/]=0.5). The capacity for polymerization of the m- and p-methy]-~,fl,fl-trifluorostyrenes-styrene systems is somewhat higher t h a n for the o-isomer. All the eopolymers of fluorinated styrenes with styrene which we synthesized form the following sequence with respect to their characteristic viseosit),: copolymers of a,fl,fl-trifluorostyrene > eopolymers of p-methyl-~,fl,fl-trifluorostyrene > copolymers of o- and m-methyl-a,fl,fl-trifluorostyrene > the eopolymer of ~,fl-difluoro-fl-chlorostyrene (Table 2). Measurement of the heat-stability of the copolymers showed that all the copolymers obtained possess a high heat stability (from 150 to 18(}° by the {FP method), the heat-stability of the copolymers rising with an increase in the content of fluorostyrene in the copolymer. The copolymer of ~,fl-difluorofl-chlorostyrene with styrene forms an exception, having a heat-stability only 4 ° higher than that of polystyrene obtained under the same conditions. However, this fact m a y be explained b y the low content of substituted styrene in the copolymer (16 moles-~o ) and the very low molecular weight of the product
([~] =0-05). CONCLUSIONS
(1) The following copolymers have been obtained and characterized for the first time: ~,fl,fl-trifluorostyrene with 2,5-dimethylstyrene and with methyl methacrylate; o- m-, and p-methyl-a,fl, fl-trifluorostyrenes with styrene; and ~,fl-difluoro-fl-chlorostyrene with styrene and with 2,5-difluorostyrene.
274
KH. U. USMANOV et al.
(2) Copolymers of ~,fl,fl-trifluorostyrene w i t h styrene with various contents of the components have been obtained and characterized. Translated by B. J. HAZZARD REFERENCES 1. D. LIVINGSTOUN, J. Polym. Sci. 20: 485, 1956 2. M. PROBER, J. Amer. Chem. Soc. 75: 968, 1953 3. A. It. GANTMAKIIEIt, Yu. L. SPIRIN and S. S. MEDVEDEV, Vysokomol. soyed. 2: 1526, 1959
INFRARED SPECTRA OF POLYSTYRENE-ACRYLONITRILE AND PERCHLOROVINYL-ACRYLONITRILE GRAFT COPOLYMERS OBTAINED UNDER THE ACTION OF y-RADIATION* K.H.U. .
USMANOV, P . 1). L A R I N , Y U . T. T A S H P U L A T O V , U . N . M U S A Y E V
and R . S. T I L L A Y E V I n s t i t u t e of Polymer Chemistry, Uzbek S.S.R. A c a d e m y of Sciences; V. I. Lenin Tashkent State University (Received 14 April 1961)
A NUMBER of investigations have been devoted to a study of the chemical and physical changes taking place in a polymer under the action of radiation on it. One of the main directions in this field is the production of graft and block copolymers under the action of 7-radiation. t t is known that the action of radiation leads to far-reaching changes in the physicochemical properties of polymers. Consequently, it may be assumed that the physicochemical properties of graft eopolymers obtained by radiation methods will be affected not only by the act of grafting but also by the action of the radiation itself. In particular, graft copolymers obtained by these methods are generally insoluble or sparingly soluble. Apparently, this fact is due to the "crosslinking" of the polymer chains or even to the formation of new bonds (for example, hydrogen bonds) under the action of the radiation. In view of this, a study of the structure of graft copolymers presents great theoretical and practical interest. In this case, one of the rational methods of..studying the structure of the polymers might be the IR spectroscopic method. This method is widely used also in the study of the chemical changes taking * Vysokomol. soyed. 4: No. 6, 907-912, 1962.
A . F . DOKUKII~'Aet al. REFERENCES
1. A. A. BERLIN, N. G. MATVEYEVA and A. I. SHERLE, Izv. Akad. Nauk SSR, Otd. khim. nauk, 2261, 1959 2. A. A. BERLIN, N. G. MATVEYEVA and A. I. SHERLE, Authors' certificate No. 126612, 7. 4. 1959 3. A. A. BERLIN, L. I. BOGUSLAVSKII, R. Kh. BURSHTEIN, N. G. MATVEYEVA, A. I. SHERLE and N. A. SHURMOVSKAYA, Dokl. Akad. Nauk SSSR 136: 1127, 1961 4. Yu. Sh. MASHKOVSKII, N. D. KOSTROVA and A. A. BERLIN, Vysokomol. soyed. 3: 1669, 1961 5. A. A. BERLIN, B. I. LIOGON'KII and V. P. PARINI, Vysokomol. soyed. 2: 683, 1960 6. T. KU~ERA, Paper at the Prague Conference on High-Molecular-Weight Compounds, 1957 7. A. EPSTEIN and B. C. WIDLY, J. Chem. Phys. 32: 324, 1960 8. A. A. BERLIN, L. G. CHERKASHINA and Ye. I. BALABANOV, Vysokomol. soyed. 3: 2, 1961 9. C. S. MARVEL, and I. H. ROSSWEILER, J. Amer. Chem. Soc. 89: 1197, 1958 10. W. J. MIDDLETON and E. L. LITTLE, J. Amer. Chem. Soc. 80: 2795, 1958 11. O. W. WEBSTER, W. MAHLER and R. E. BENSON, J. Org. Chem. 25: 1470, 1960 12. A. A. BERLIN and N. G. MATVEYEVA, Dokl. Akad. Nauk SSSR 140: 368, 1961 13. T. L. CAIRNS etal., J. Amer. Chem. Soe. 80: 2775, 1958, 14. J. F. STEMBACH and J. H. BURNS, J. Amer. Chem. Soc. 80: 1839, 1958 15. T. L. CAIRNS et al., J. Amer. Chem. Soc. 80: 2775, 1958
SYNTHESIS AND POLYMERIZATION (COPOLYMERIZATION) OF FLUORINATED STYRENESeI. COPOLYMERIZATION OF FLUORINATED STYRENE AND VINYL MONOMERS* A. F. DOKUKINA, YE. I. YEGOROVA, G. V. KAZENNIKOVA, M. M. KOTON, K. A. KOCHESHKOV, Z. A. SMIRNOVA ,and T. V. TALALAYEVA Institute of High-Molecular-Weight Compounds, U.S.S.R. Academy of Sciences {Received 11 April 1961)
OF THE substituted polystyrenes, the polymers with substituents in the vinyl
chain are of great interest with respect to their physicochemical properties. I t has b e e n discovered [1-3] t h a t poly-a,fl,fl-trifluorostyrene a n d its c o p o l y m e r s w i t h s t y r e n e o b t a i n e d b y t h e emulsion m e t h o d possess a high h e a t - s t a b i l i t y similar t o t h a t o f p o l y t e t r a f l u o r o e t h y l e n e a n d good dielectric properties, while a t t h e same t i m e being soluble in organic solvents. H o w e v e r , the a u t h o r s n o t e d [1, 2] t h a t t h e h o m o p o l y m e r s o f a,fl,fl-trifluorostyrene are brittle a n d t h e i r prep a r a t i o n is difficult because t h e p o l y m e r i z a t i o n is a c c o m p a n i e d b y intense dimerization of the monomer. * Vysokomol. soyed. 4: No. 6, 885-888, 1962.
Synthesis and polymerization of fluorinated styrenes
271
We have carried out experiments on the production of copolymers of a,fl,fltrifluorostyrene, o-, m-, and p-methyl-g,fl,fl-trifluorostyrenes, and a,fl-difluorofl-chlorostyrene with styrene, 2,5-dimethylstyrene, 2,5-difluorostyrene, and methyl methacrylate. T A B L E 1. P R O P E R T I E S
Monomer
a, fl, fl-trifluorostyrene o-methyl-~,fl,fl-trifluorostyrene m-methyl-a,fl,fl-trifluorostyrene p-methyl- ~, fl, fl-trifluorostyrene a, fl-difluoro-fl-ehlorostyrene 2,5-difluorostyrene
OF T H E MONOMERS
F content (%)
B.p. (°C) (mm)
20 ?~D
67-70 (75) 72 (60) 89-90 (70) 83-5 (65) 56-58 (10) 56 (30)
1"4770 1.4710 1.4694 1.4823 1.5179 (19) 1.4982
Found
Calculated
36"5 33.01 32.95 33.05
36.07 33.14 33.14 33-14
27.46 27.54
27.13
EXPERIMENTAL The monomers used for copolymerization were carefidly purified and fractionated at a reduced pressure (Table 1). The copolymerization was carried out in emulsion b y a method developed by us. A n emulsion consisting of water (80-85~) of the weight of the reaction mixture), a n emulsifier (sodium stearate or oleate--2"5% of the total mixture), a persulphate initiator (0.5%), a n d a pI-Lregulator was placed in a three-necked flask fitted with a funnel-shaped mechanical stirrer and a dropping funnel. The contents of the flask were first heated to 80-90 ° and then a mixture of monomers containing a second initiator--azoisobutyronitrile (0"5~o of the weight of the monomers)--was added to it at 60 ° after which the reaction mixture was stirred for a long time at 60 °. The emulsion was broken with a 3~o solution of sulphuric acid. The copolymer isolated was repeatedly washed with water and hot methyl alcohol, was repreeipitated, a n d was then dried at an elevated temperature in vacuum. The composition of the copolymers was determined from the fluorine content. Using the method described, we obtained 11 copolymers of a,B, fl-trifluoro-o-, -m-, a n d -p-methylstyrenes a n d a,fl, fl-halogen-substituted styrenes with styrene, 2,5-dimethylstyrene, 2,5-difluorostyrene, a n d methyl methacrytate (Table 2). All the products obtained were readily soluble in organic solvents for thermoplastic polymers, which made it posible for us to determine the characteristic viscosities (Table 2) of benzene solutions at 20 ° and the heat.stability of the copolymers b y the I F P method.
DISCUSSION OF THE RESULTS In the study of the copolymerization of styrenes fluorinated in the side-chain w i t h v i n y l m o n o m e r s i t w a s f o u n d t h a t , o f a l l t h e p a i r s o f m o n o m e r s t h a t we tested, the c o p o l y m e r i z a t i o n of a,fl,fl-trifluorostyrene w i t h 2 , 5 - d i m e t h y l s t y r e n e t o o k p l a c e m o s t r a p i d l y . I t c a n b e s e e n f r o m T a b l e 2 t h a t t h i s c o p o l y m e r is formed in 4 hours w i t h a 9 0 % c o n v e r s i o n at a c o n t e n t of ~,fl,fl-trifluorostyrene o f 50.54 m o l e s - % a n d h a s q u i t e a h i g h m o l e c u l a r w e i g h t ([~/] = 1.1). T h e c o p o l y -
A.F. I)OKUKII~Aet al.
272
TABLE 2. TIME OF COPOLYMERIZATION,YIELD OF COPOLYMERS,THEIR COMPOSITIONS AND CHARACTERISTICVISCOSITIES Time of experiment (hr)
Composition of the copolymer (moles-%)
Yield of copolymer
(%)
M1
[
Characteristic viscosity of benzene solutions of the copolymers at 20 °
Me
Copolymers of a,fl, fl-trifluorostyrene (M1) with styrene (Me) 8 7 8 8
]
74 70 60 40
/ / i
28.53 39"77 48"53 53*75
71"47 60"23 51"47 46"24
/
2.7 2"8 1"8 0"9
Copolymers of a,fl, fl-trifluorostyrene (M1) with 2,5-dimethylstyrene (MQ 4 4
90 50
] i
50"54 60"77
49.16 39"23
1.1 0"6
Copolymers of g,fl, fl-trifluorostyrene (M1) with methyl methacrylate (Ms) 6 11
[ J
-41
I I
43-29 I 153"88
56"71 46.12
0"4 0-2
Copolymers of m-mothyl-a,fl, fl-trifluorostyrene (M1) with styrene (Me) 2.5 I 40 ] 46.26 I 53.73 I 0-5 Copolymer of o-methyl-~,fl, fl-trifluorostyrene (M1) with styrene (M2) 33 I 11 t 50.41 I 49.59 I 0.5 Copolymer ofp-methyl-a,fl, fl-trifluorostyrene (M1) with styrene (Me) 7 I 55 46.97 53"03 2.0 7 / 64 36"77 63.23 1.4 20
Copolymer of a,fl-difluoro-fl-ehlorostyrene (M1) with styrene (Me) 1 30 I 16.00 j 84.00 I 0.05
Copolymer of ~,/~-difluoro-fl-ehlorostyrene (M1) with 2,5-difluorostyrene (Me) 20 I 14 I t I o.~ m e r i z a t i o n o f a,fl,fl-trifluorostyrene with s t y r e n e takes place more s l o w l y - - f o r a c o p o l y m e r containing 48.53 moles-% o f the fluorinated styrene, the yield is o n l y 6 0 % a f t e r 8 hours' copolymerization. On c o m p a r i n g the conversion a n d the characteristic viscosity of copolymers o f ~,fl,fl-trifluorostyrene o f different compositions (Table 2) it m u s t be n o t e d t h a t t h e i n t r o d u c t i o n of t h e fluorine-containing c o m p o n e n t reduces the yield o f c o p o l y m e r a n d its characteristic viscosity, and, consequently, its molecular weight. Thus, on increasing t h e c o n t e n t o f a,fl,fl-trifluorostyrene in the c o p o l y m e r f r o m 28.53 to 53.75 moles-~o, t h e characteristic viscosity falls f r o m 2.7 to 0.9, a n d the yield o f copolymers a t r o u g h l y the same p o l y m e r i z a t i o n t i m e diminishes f r o m 74 to 40~/o.
Synthesis and polymerization of fluorinated styrenes
273
The copolymerization of ~,fl,fl-trifluorostyrene with methyl methacrylate, in all probability, goes with more difficulty than that with styrene and 2,5dimethylstyrene. After 11 hours' copolymerization, the yield of copolymer with methyl methacrylate amounts to only 41~o at 53.88 moles-~/o of a,fl,fltrifluorostyrene. The copolymers of a,fl, fl-trifluorostyrene with methyl methacrylate possess a relatively low molecular weight--the characteristic viscosity is between 0.4 and 0.2. Iu studying the copolymerization of a,fl-difluoro-fl-chlorostyrene-styrene system, it was found that the replacement of one fl fluorine atom in the vinyl chain of a,fl,fl-trifluorostyrene by a chlorine atom markedly diminishes the capacity of the substituted styrene for copolymerization with styrene. After 20 hours, the eopolymer of a,fl-difluoro-fl-chlorostyrene with styrene is formed in a yield of only 30% and has a very low characteristic viscosity [~]=0.05, in spite of the fact that the content of substituted styrene in the eopolymer is only 16 moles-~/o. The introduction of a methyl group into the benzene nucleus of ~,fl,fl-trifluorostyrene also reduces the capacity of the monomer for copolymerization. o-, m-, and p-methyl-a,fl,fl-trifluorostyrenes copolymerize with styrene more slowly t h a n unsubstituted a,fl,fl-trifluorostyrene. The copolymerization of the o-methyl-a,fl,fl-trifluorostyrene-styrene system is particularly strongly retarded. After 33 hours' polymerization a polymer is obtained with a yield of only 11%, although it has a high polymerization coefficient ([~/]=0.5). The capacity for polymerization of the m- and p-methy]-~,fl,fl-trifluorostyrenes-styrene systems is somewhat higher t h a n for the o-isomer. All the eopolymers of fluorinated styrenes with styrene which we synthesized form the following sequence with respect to their characteristic viseosit),: copolymers of a,fl,fl-trifluorostyrene > eopolymers of p-methyl-~,fl,fl-trifluorostyrene > copolymers of o- and m-methyl-a,fl,fl-trifluorostyrene > the eopolymer of ~,fl-difluoro-fl-chlorostyrene (Table 2). Measurement of the heat-stability of the copolymers showed that all the copolymers obtained possess a high heat stability (from 150 to 18(}° by the {FP method), the heat-stability of the copolymers rising with an increase in the content of fluorostyrene in the copolymer. The copolymer of ~,fl-difluorofl-chlorostyrene with styrene forms an exception, having a heat-stability only 4 ° higher than that of polystyrene obtained under the same conditions. However, this fact m a y be explained b y the low content of substituted styrene in the copolymer (16 moles-~o ) and the very low molecular weight of the product
([~] =0-05). CONCLUSIONS
(1) The following copolymers have been obtained and characterized for the first time: ~,fl,fl-trifluorostyrene with 2,5-dimethylstyrene and with methyl methacrylate; o- m-, and p-methyl-a,fl, fl-trifluorostyrenes with styrene; and ~,fl-difluoro-fl-chlorostyrene with styrene and with 2,5-difluorostyrene.
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(2) Copolymers of ~,fl,fl-trifluorostyrene w i t h styrene with various contents of the components have been obtained and characterized. Translated by B. J. HAZZARD REFERENCES 1. D. LIVINGSTOUN, J. Polym. Sci. 20: 485, 1956 2. M. PROBER, J. Amer. Chem. Soc. 75: 968, 1953 3. A. It. GANTMAKIIEIt, Yu. L. SPIRIN and S. S. MEDVEDEV, Vysokomol. soyed. 2: 1526, 1959
INFRARED SPECTRA OF POLYSTYRENE-ACRYLONITRILE AND PERCHLOROVINYL-ACRYLONITRILE GRAFT COPOLYMERS OBTAINED UNDER THE ACTION OF y-RADIATION* K.H.U. .
USMANOV, P . 1). L A R I N , Y U . T. T A S H P U L A T O V , U . N . M U S A Y E V
and R . S. T I L L A Y E V I n s t i t u t e of Polymer Chemistry, Uzbek S.S.R. A c a d e m y of Sciences; V. I. Lenin Tashkent State University (Received 14 April 1961)
A NUMBER of investigations have been devoted to a study of the chemical and physical changes taking place in a polymer under the action of radiation on it. One of the main directions in this field is the production of graft and block copolymers under the action of 7-radiation. t t is known that the action of radiation leads to far-reaching changes in the physicochemical properties of polymers. Consequently, it may be assumed that the physicochemical properties of graft eopolymers obtained by radiation methods will be affected not only by the act of grafting but also by the action of the radiation itself. In particular, graft copolymers obtained by these methods are generally insoluble or sparingly soluble. Apparently, this fact is due to the "crosslinking" of the polymer chains or even to the formation of new bonds (for example, hydrogen bonds) under the action of the radiation. In view of this, a study of the structure of graft copolymers presents great theoretical and practical interest. In this case, one of the rational methods of..studying the structure of the polymers might be the IR spectroscopic method. This method is widely used also in the study of the chemical changes taking * Vysokomol. soyed. 4: No. 6, 907-912, 1962.