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Initiation of polymerization of polar monomers by polyarylvinylenes
INITIATION OF POLYMERIZATION OF POLAR MONOMERS BY POLYARYLVINYLENES* A. A. BERLIN, M. V. VOZttILOVA, G. I. BAlqTSYREV, M. I. CttERKASttIN a n d I. M. PAlqAIOTOV Institute of Chemical Physics, U.S.S.R. Academy of Sciences
(Received 5 May 1970)
Ilq POLYMERS with a system of ~-conjugation (PCS) as the conjugated sequence increases in length the ionization potential (I) decreases, and this enables them to form charge-transfer complexes with various electron-acceptor compounds [1-7]. This specific feature of PCS's enables them to be used as initiators of the polymerization of monomers with a high affinity for electrons [8-10]. It has been shown t h a t by initiation with a PCS it is possible to polymerize at 150 ° and above such difficultly-polymerizable monomers as tetracyanoethylene and derivatives of maleic acid. In this paper we report an investigation of the initiating activity of polyphenylacetylene (PPA) in polymerization and copolymerization of methyl methacrylate (MMA), acrylonitrile (AN) and styrene (St). EXPERIMENTAL The monomers were freed from inhibitors and impurities by the usual methods [11, 12]. They were stored over calcium hydride and redistilled immediately before use (MMA, 45-45.5°/100 ram; St, 33+0-2°/10 ram; AN, 78=t=0.1°/760 mm). The water content of the monomers by the Fischer method was not more than 10 -3 mole/1. The solvents, i.e. benzene, dimethylformamide (DMF) and tetrahydrofuran (THF), were purified and dried by standard methods and stored in glass ampoules under argon. Polyphenylaeetylene with ~ f n = 5 5 0 was prepared with the a-TiC13+Al(C3tts)3 (molar ratio 1 : 2) catalyst system, in benzene at 70 °. The benzene-soluble fraction of the polymer was twice reprecipitated by methanol, dried in vacuo over P205 at 65 ° and stored in an atmosphere of argon. The dilatometric method was used for study of the polymerization kinetics. Dilatemeters, thoroughly dried by heating and evacuation, with a spherical bulb of capacity 12-16 em 3 and a scale division of 0.01 em 3, were filled in a current of argon. The liquid components were measured out by distillation from graduated ampoules and the quantities were confirmed by weighing on an analytical balance. Air was removed from the filled dilatometers by repeated freezing and evacuation, and they were then sealed. The reaction was carried out in a thermostat at temperatures from 50 to 100 °, the precision of temperature control being q-0.1 °. I n all instances a control experiment (thermal polymerization of MMA in * Vysokomol. soyed. A14: No. 9, 1906-1909, 1972. 2132
Polymerization of polar monomers
2133
the absence of PPA) was run. The product was precipitated by methanol and dried to constant weight. The copolymer were isolated by successive extraction with aeetonitrile (MMA homopolymer) and a benzene : petroleum ether (55 : 45 parts by volume) mixture (unreacted PPA). The infrared spectra of the polymers were recorded in a UR-20 spectrometer in the 700-4000 cm -1 region. RESULTS AND DISCUSSION
The addition of catalytic a m o u n t s ( 0 . 5 - 5 ~ b y weight) of P P A to MMA brings a b o u t p o l y m e r i z a t i o n of t h e l a t t e r a t t e m p e r a t u r e s below 100 ° in t h e absence of o r d i n a r y p o l y m e r i z a t i o n initiators, whereas in this t e m p e r a t u r e region t h e r m a l p o l y m e r i z a t i o n of MMA occurs to a slight e x t e n t only (~<2e/o in 6 hr) (Fig. la). T h e light-yellow p r o d u c t h a d a n intrinsic viscosity of 0.400 dl/g a f t e r r e m o v a l of MMA h o m o p o l y m e r a n d P P A . T h e infrared s p e c t r u m of the p o l y m e r contains a b s o r p t i o n bands characteristic of t h e m o n o - s u b s t i t u t e d benzene ring
I
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8
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Time, hr,
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FIo. 1. Typical kinetic curves of the polymerization of MMA in the presence of PPA (a) and benzoquinone (b). a: 1, 3--0; 2, 5, 6, 8--42.3; 4, 7--4.38 g/1. of PPA; temperature, °C: 50 (1, 2); 70 (4, 5); 80 (6); 100 (3, 7, 8); b: 1, 4--0; 2, 3, 5, 6--42 g/1. of PPA; benzoquinone, moles per PPA unit: 0.0019 (1, 5); 0.038 (2); 0.019 (3); without benzoquinone (4, 6). (3027, 1600, 1493, 770 and 715 cm-1), t h e m e t h o x y l group (1300-1150 cm -1) and t h e c a r b o n y l group (1754 cm-1). T h e s p e c t r u m does n o t contain bands assigned to d i s u b s t i t u t e d benzene rings. I t m a y t h u s be assumed t h a t in this cop o l y m e r addition of MMA ¢o t h e polyene chain of P P A occurs p r e d o m i n a n t l y . P o l y m e r i z a t i o n of MMA is inhibited b y quinones (Fig. lb). The i n t r o d u c t i o n of 0.05 moles of b e n z o q u i n o n e per P P A u n i t c o m p l e t e l y stops t h e process. Carbon dioxide, w a t e r and strong electron acceptors ( t e t r a c y a n o e t h y l e n e ) are efficient inhibitors of t h e reaction.
2134
A.A.
B~.PJ~I~ et al.
Typical kinetic curves of polymerization of MMA are shown in Fig. la. There is no induction period in the reaction. The rate of polymerization is constant at a given degree of conversion. The effect of the catalyst concentration on the yield of reaction products is small (a tenfold increase in the amount of P P A doubles the total yield of polymeric products). Log-log graphs of the dependence of the reaction rate on the concentration of the reactants (MMA and PPA) are linear. The slopes of the graphs show t h a t the reaction is of the second order with respect to monomer and of a fractional order (0-25) with respect to catalyst. The reaction rate constants fit the Arrhenius equation [13] satisfactorily. The over-all energy of activation for polymerization in bulk was found to be 13.6 -4-0.4 kcal/mole, which is very near to the energy of activation for oxidation-reduction processes and a little less t h a n the values for polymerization of MMA initiated by benzoyl peroxide (20 keal/mole) and for thermal polymerization (16 kcal/mole) [14]. /'0 •~ o.~
~1o
/
17
-
.~ ~2
2 0
2,5
50
76
Quan~i~ o f solvent, mole %
FIG. 2
o
I I I I I I I I / O.Z 0-4 0.,6" 0.6' 1.0 AN in monomer n,'//Au.ne, mo/e fpac;'/on
FIG. 3
FIG. 2. Dependence of the degree of conversion on the dielectric constant of the medium (after 4 hr): 1--DMF; 2--benzene; 70°. FIG. 3. Dependence of the composition of polyacrylate blocks on the ratio of the monomers in:/--anionic [15] ~nd 2--radical polymerization. The points indicate experimental results. When polymerization is carried out in solution (benzene, DMF, THF) a number of features characteristic of ionic processes are manifested. On passing from benzene to THF, i.e. as the donor properties of the solvent are increased, the rate of polymerization increases ten times (from 2.20 × 10 -s to 24.4 × 10 -6 mole]l./sec). When the concentration of monomer in benzene is altered only the dilution effect is seen, whereas in DMF the over-all rate of the process varies in parallel with the change in the dielectric constant of the system (Fig. 2). Further information on the mechanism of propagation was obtained from a
Polymerization of polar monomers
2135
s t u d y of th e products of copolymerization of St with MMA and AN with MMA in t h e presence of PPA. Styrene was copolymerized with MMA in bulk and AN with MMA in solution in T H F . The concentration of monomers in t he initial and final mixtures was determined chromatographically (Apiezon L on Chromosorb). The composition of t he copolymers was determined by infrared spectroscopic and elementary analysis. Lu copolymerization of equivalent amounts of St and MMA the concentration of t he monomers in the copolymer is close to the concentration in th e initial reaction mixture and is independent of the degree of conversion. The curve of the dependence of copolymer composition (ratio of A_N to MMA) on t he ratio of th e monomers in t he initial reaction mixture (Fig. 3) coincides satisfactorily with t he curve calculated for radical copolymerization [15]. Our experimental results show t h a t the mechanism of initiation of t he polymerization of polar monomers by polyarylvinylenes is complex. CONCLUSIONS
(1) I t is shown t h a t in principle it is possible to iniViate polymerization with a conjugated system in t her m al polymerization of polar monomers under mild conditions (at 50-100°). (2) The polymerization of m e t hyl methacrylate initiated by polyphenylacetylene has been investigated, and t he main kinetic relationships were studied. (3) Methyl methacrylate has been copolymerized with styrene and with acrylonitrile in th e presence of polyphenylacetylene. Translated by E. O. PHTr.rr.~S
REFERENCES 1. A. A. BFA~LIN, J. Polymer Sei. C22: 2, 1969 2. V. V. PEN'KOVSlgH and V. S. KUTS, Teor. i eksp. khim. 1: 818, 1965; 8: 106, 1967
3. N. A. MARKOVA, Dissertation, 1970 4. A. A. BERLIN, M. I. CHERKASHIN, Yu. G. ASEYEV and I. M. SItCHERBAKOVA,
5. 6. 7. 8. 9. 10. 11. 12.
Yysokomel. soyed. 6: 1773, 1964 (Translated in Polymers Sei. U.S.S.R. 6: 10, 1965, 1964) A. A. BERLIN, M. I. CHERKASHIN and I. P. CHERNYSHOVA. Izv. Akad. Nauk SSSR, ser. khim., 57, 1967 B. G. ZADONTSEV, I. D. KAL1KItMAN, M. I. CHERKASHIN and A. A. BERLIN, Vysokomol. soyed. All: 1318, 1969 (Translated in Polymers Sei. U.S.S.R. 11: 6, 1497, 1969) I. D. KAI.EKH:MAN, M. I. CHERKASHIN and A. A. BERLIN, Vysokomol. soyed. A18: 1456, 1971 (Translated in Polymer Sci. U.S.S.R. 13: 7, 1637, 1971) A. A. BERLIN and I. G. MATVEYEVA, Dokl. Akad. Nauk SSSR 140: 368, 1961; Vysokoreel. soyed. 8: 736, 1966 (Translated in Polymer Sci. U.S.S.R. 8: 4, 808, 1966) A. A. BERLIN, M. I. CHERKASHIN, O. G. SEL'SKAYA and V. Yo. LIMANOV, Vysokoreel. soyed 1: 1817, 1959 (Not translated in Polymer Sci. U.S.S.R.) B. G. ZADONTSEV, M. I. CHERKASHIN and A. A. BERLIN, Izv. Akad. ~Tauk SSSR, ser. khim., 2065, 1967; Vysokemol. soyed. B9: 91, 1967 (Not translated in Polymer Sei. U.S.S.R.) G. GOLDFINGER and K. E. LAUTERBACH, J. Polymer Sei. 3: 145, 1948 K. NOZAKI and P. D. BARTLETT, J. Amer. Chem. Soc. 68: 2377, 1948
2136
N. G. SHCH~RB~KOViet al.
13. C. H. BAMFORD and T. E. F. WHITE, Trans. Faraday Soc. 52: 716, 1956 14. G. P. GLADYSHEV, Polimerizatsiya vinil'nykh monomerov (Polymerization of Vinyl Monomers). p. 38, Alma-Ata, 1964 15. S. Ye. BRESLER and B. L. YERUSALIMSKII, Fizika i khimiya makromolekul (Physics and Chemistry of Macromolecules). pp. 265, 363, Izd. "Nauka", 1965
PHASE SEPARATION IN MIXTURES OF SOLUTIONS OF SECONDARY CELLULOSE ACETATE AND POLYACRYLONITRILE* N. G. SHCHERBAKOVA, V. A. LAlVDYSHEVA, M. I. AI~AlV'IlVA, V. F. VOLXOV a n d Y~. P. KUZ~ETSOVA Research Institute of Synthetic Resins Okhtinskii Chemical Combine (Received 19 October 1970)
IT ~ s b e e n s h o w n p r e v i o u s l y t h a t t h e s t r u c t u r e a n d p r o p e r t i e s of fibres f r o m m i x t u r e s of s e c o n d a r y cellulose a c e t a t e (SCA) a n d polyacrylonitrile (PAN) are d e p e n d e n t on t h e presence of a g r a f t c o p o l y m e r of these t w o p o l y m e r s [1]. Since t h e s t r u c t u r e a n d p r o p e r t i e s of fibres are largely d e p e n d e n t on t h e s t r u c t u r e a n d p r o p e r t i e s of t h e spinning solution, it was of i n t e r e s t to e x a m i n e t h e effect of t h e g r a f t c o p o l y m e r on t h e s t a t e of m i x t u r e s of solutions of cellulose a c e t a t e a n d P A N . I t is k n o w n t h a t solutions of SCA a n d P A N in d i m e t h y l f o r m a m i d e are n o t c o m p a t i b l e , w h e t h e r or n o t t h e g r a f t c o p o l y m e r is present, a n d in t i m e t h e m i x t u r e s s e p a r a t e i n t o t w o p h a s e s [2, 3]. T h e p r e s e n t p a p e r describes a s t u d y of p h a s e s e p a r a t i o n in m i x t u r e s of solutions o f SCA a n d P A N , w i t h a n d w i t h o u t g r a f t copolymer.
EXPERIMENTAL The following materials were used: 1) commercial SCA with M v : 100,000 and an acetyl content of 55'5 Yo, and degraded samples with M ~ : 80,000, 60,000 and 40,000; 2) commercial PAN with Mv:40,000, and samples prepared by radical polymerization and having My 30,000, 20,000 and 10,000; 3) SCA/PAN graft eopolymer, isolated from the product of graft copolymerization by selective dissolution of the homopolymers, the ratio of combined SCA : PAN being 40 : 60, with M~ of the grafted PAN chains equal to 180,000. The chemically pure DMF had d:0.9484 (22°), a refractive index n:1.4294 (22 °) and a boiling point of 153 °. The polymer mixtures were prepared by separately dissolving SCA, PAN and the SCA/PAN copolymer in DMF and mixing the solutions. The ratio of the polymeric components in the phases was found from the nitrogen content of the precipitated product. The composition of SCA-PAN-SCA/PAN mixtures * Vysokomol soyed. A14: No. 9, 1910-1916, 1972.
(Received 5 May 1970)
Ilq POLYMERS with a system of ~-conjugation (PCS) as the conjugated sequence increases in length the ionization potential (I) decreases, and this enables them to form charge-transfer complexes with various electron-acceptor compounds [1-7]. This specific feature of PCS's enables them to be used as initiators of the polymerization of monomers with a high affinity for electrons [8-10]. It has been shown t h a t by initiation with a PCS it is possible to polymerize at 150 ° and above such difficultly-polymerizable monomers as tetracyanoethylene and derivatives of maleic acid. In this paper we report an investigation of the initiating activity of polyphenylacetylene (PPA) in polymerization and copolymerization of methyl methacrylate (MMA), acrylonitrile (AN) and styrene (St). EXPERIMENTAL The monomers were freed from inhibitors and impurities by the usual methods [11, 12]. They were stored over calcium hydride and redistilled immediately before use (MMA, 45-45.5°/100 ram; St, 33+0-2°/10 ram; AN, 78=t=0.1°/760 mm). The water content of the monomers by the Fischer method was not more than 10 -3 mole/1. The solvents, i.e. benzene, dimethylformamide (DMF) and tetrahydrofuran (THF), were purified and dried by standard methods and stored in glass ampoules under argon. Polyphenylaeetylene with ~ f n = 5 5 0 was prepared with the a-TiC13+Al(C3tts)3 (molar ratio 1 : 2) catalyst system, in benzene at 70 °. The benzene-soluble fraction of the polymer was twice reprecipitated by methanol, dried in vacuo over P205 at 65 ° and stored in an atmosphere of argon. The dilatometric method was used for study of the polymerization kinetics. Dilatemeters, thoroughly dried by heating and evacuation, with a spherical bulb of capacity 12-16 em 3 and a scale division of 0.01 em 3, were filled in a current of argon. The liquid components were measured out by distillation from graduated ampoules and the quantities were confirmed by weighing on an analytical balance. Air was removed from the filled dilatometers by repeated freezing and evacuation, and they were then sealed. The reaction was carried out in a thermostat at temperatures from 50 to 100 °, the precision of temperature control being q-0.1 °. I n all instances a control experiment (thermal polymerization of MMA in * Vysokomol. soyed. A14: No. 9, 1906-1909, 1972. 2132
Polymerization of polar monomers
2133
the absence of PPA) was run. The product was precipitated by methanol and dried to constant weight. The copolymer were isolated by successive extraction with aeetonitrile (MMA homopolymer) and a benzene : petroleum ether (55 : 45 parts by volume) mixture (unreacted PPA). The infrared spectra of the polymers were recorded in a UR-20 spectrometer in the 700-4000 cm -1 region. RESULTS AND DISCUSSION
The addition of catalytic a m o u n t s ( 0 . 5 - 5 ~ b y weight) of P P A to MMA brings a b o u t p o l y m e r i z a t i o n of t h e l a t t e r a t t e m p e r a t u r e s below 100 ° in t h e absence of o r d i n a r y p o l y m e r i z a t i o n initiators, whereas in this t e m p e r a t u r e region t h e r m a l p o l y m e r i z a t i o n of MMA occurs to a slight e x t e n t only (~<2e/o in 6 hr) (Fig. la). T h e light-yellow p r o d u c t h a d a n intrinsic viscosity of 0.400 dl/g a f t e r r e m o v a l of MMA h o m o p o l y m e r a n d P P A . T h e infrared s p e c t r u m of the p o l y m e r contains a b s o r p t i o n bands characteristic of t h e m o n o - s u b s t i t u t e d benzene ring
I
tg
a
"El //"
.,I/
/
$
q
!'II/? ~ +M
0
r~
2
J
/
22
i
b
...i ×..
4
6
~'me , hr
8
0
I
2
,3
4
J
Time, hr,
•
7
FIo. 1. Typical kinetic curves of the polymerization of MMA in the presence of PPA (a) and benzoquinone (b). a: 1, 3--0; 2, 5, 6, 8--42.3; 4, 7--4.38 g/1. of PPA; temperature, °C: 50 (1, 2); 70 (4, 5); 80 (6); 100 (3, 7, 8); b: 1, 4--0; 2, 3, 5, 6--42 g/1. of PPA; benzoquinone, moles per PPA unit: 0.0019 (1, 5); 0.038 (2); 0.019 (3); without benzoquinone (4, 6). (3027, 1600, 1493, 770 and 715 cm-1), t h e m e t h o x y l group (1300-1150 cm -1) and t h e c a r b o n y l group (1754 cm-1). T h e s p e c t r u m does n o t contain bands assigned to d i s u b s t i t u t e d benzene rings. I t m a y t h u s be assumed t h a t in this cop o l y m e r addition of MMA ¢o t h e polyene chain of P P A occurs p r e d o m i n a n t l y . P o l y m e r i z a t i o n of MMA is inhibited b y quinones (Fig. lb). The i n t r o d u c t i o n of 0.05 moles of b e n z o q u i n o n e per P P A u n i t c o m p l e t e l y stops t h e process. Carbon dioxide, w a t e r and strong electron acceptors ( t e t r a c y a n o e t h y l e n e ) are efficient inhibitors of t h e reaction.
2134
A.A.
B~.PJ~I~ et al.
Typical kinetic curves of polymerization of MMA are shown in Fig. la. There is no induction period in the reaction. The rate of polymerization is constant at a given degree of conversion. The effect of the catalyst concentration on the yield of reaction products is small (a tenfold increase in the amount of P P A doubles the total yield of polymeric products). Log-log graphs of the dependence of the reaction rate on the concentration of the reactants (MMA and PPA) are linear. The slopes of the graphs show t h a t the reaction is of the second order with respect to monomer and of a fractional order (0-25) with respect to catalyst. The reaction rate constants fit the Arrhenius equation [13] satisfactorily. The over-all energy of activation for polymerization in bulk was found to be 13.6 -4-0.4 kcal/mole, which is very near to the energy of activation for oxidation-reduction processes and a little less t h a n the values for polymerization of MMA initiated by benzoyl peroxide (20 keal/mole) and for thermal polymerization (16 kcal/mole) [14]. /'0 •~ o.~
~1o
/
17
-
.~ ~2
2 0
2,5
50
76
Quan~i~ o f solvent, mole %
FIG. 2
o
I I I I I I I I / O.Z 0-4 0.,6" 0.6' 1.0 AN in monomer n,'//Au.ne, mo/e fpac;'/on
FIG. 3
FIG. 2. Dependence of the degree of conversion on the dielectric constant of the medium (after 4 hr): 1--DMF; 2--benzene; 70°. FIG. 3. Dependence of the composition of polyacrylate blocks on the ratio of the monomers in:/--anionic [15] ~nd 2--radical polymerization. The points indicate experimental results. When polymerization is carried out in solution (benzene, DMF, THF) a number of features characteristic of ionic processes are manifested. On passing from benzene to THF, i.e. as the donor properties of the solvent are increased, the rate of polymerization increases ten times (from 2.20 × 10 -s to 24.4 × 10 -6 mole]l./sec). When the concentration of monomer in benzene is altered only the dilution effect is seen, whereas in DMF the over-all rate of the process varies in parallel with the change in the dielectric constant of the system (Fig. 2). Further information on the mechanism of propagation was obtained from a
Polymerization of polar monomers
2135
s t u d y of th e products of copolymerization of St with MMA and AN with MMA in t h e presence of PPA. Styrene was copolymerized with MMA in bulk and AN with MMA in solution in T H F . The concentration of monomers in t he initial and final mixtures was determined chromatographically (Apiezon L on Chromosorb). The composition of t he copolymers was determined by infrared spectroscopic and elementary analysis. Lu copolymerization of equivalent amounts of St and MMA the concentration of t he monomers in the copolymer is close to the concentration in th e initial reaction mixture and is independent of the degree of conversion. The curve of the dependence of copolymer composition (ratio of A_N to MMA) on t he ratio of th e monomers in t he initial reaction mixture (Fig. 3) coincides satisfactorily with t he curve calculated for radical copolymerization [15]. Our experimental results show t h a t the mechanism of initiation of t he polymerization of polar monomers by polyarylvinylenes is complex. CONCLUSIONS
(1) I t is shown t h a t in principle it is possible to iniViate polymerization with a conjugated system in t her m al polymerization of polar monomers under mild conditions (at 50-100°). (2) The polymerization of m e t hyl methacrylate initiated by polyphenylacetylene has been investigated, and t he main kinetic relationships were studied. (3) Methyl methacrylate has been copolymerized with styrene and with acrylonitrile in th e presence of polyphenylacetylene. Translated by E. O. PHTr.rr.~S
REFERENCES 1. A. A. BFA~LIN, J. Polymer Sei. C22: 2, 1969 2. V. V. PEN'KOVSlgH and V. S. KUTS, Teor. i eksp. khim. 1: 818, 1965; 8: 106, 1967
3. N. A. MARKOVA, Dissertation, 1970 4. A. A. BERLIN, M. I. CHERKASHIN, Yu. G. ASEYEV and I. M. SItCHERBAKOVA,
5. 6. 7. 8. 9. 10. 11. 12.
Yysokomel. soyed. 6: 1773, 1964 (Translated in Polymers Sei. U.S.S.R. 6: 10, 1965, 1964) A. A. BERLIN, M. I. CHERKASHIN and I. P. CHERNYSHOVA. Izv. Akad. Nauk SSSR, ser. khim., 57, 1967 B. G. ZADONTSEV, I. D. KAL1KItMAN, M. I. CHERKASHIN and A. A. BERLIN, Vysokomol. soyed. All: 1318, 1969 (Translated in Polymers Sei. U.S.S.R. 11: 6, 1497, 1969) I. D. KAI.EKH:MAN, M. I. CHERKASHIN and A. A. BERLIN, Vysokomol. soyed. A18: 1456, 1971 (Translated in Polymer Sci. U.S.S.R. 13: 7, 1637, 1971) A. A. BERLIN and I. G. MATVEYEVA, Dokl. Akad. Nauk SSSR 140: 368, 1961; Vysokoreel. soyed. 8: 736, 1966 (Translated in Polymer Sci. U.S.S.R. 8: 4, 808, 1966) A. A. BERLIN, M. I. CHERKASHIN, O. G. SEL'SKAYA and V. Yo. LIMANOV, Vysokoreel. soyed 1: 1817, 1959 (Not translated in Polymer Sci. U.S.S.R.) B. G. ZADONTSEV, M. I. CHERKASHIN and A. A. BERLIN, Izv. Akad. ~Tauk SSSR, ser. khim., 2065, 1967; Vysokemol. soyed. B9: 91, 1967 (Not translated in Polymer Sei. U.S.S.R.) G. GOLDFINGER and K. E. LAUTERBACH, J. Polymer Sei. 3: 145, 1948 K. NOZAKI and P. D. BARTLETT, J. Amer. Chem. Soc. 68: 2377, 1948
2136
N. G. SHCH~RB~KOViet al.
13. C. H. BAMFORD and T. E. F. WHITE, Trans. Faraday Soc. 52: 716, 1956 14. G. P. GLADYSHEV, Polimerizatsiya vinil'nykh monomerov (Polymerization of Vinyl Monomers). p. 38, Alma-Ata, 1964 15. S. Ye. BRESLER and B. L. YERUSALIMSKII, Fizika i khimiya makromolekul (Physics and Chemistry of Macromolecules). pp. 265, 363, Izd. "Nauka", 1965
PHASE SEPARATION IN MIXTURES OF SOLUTIONS OF SECONDARY CELLULOSE ACETATE AND POLYACRYLONITRILE* N. G. SHCHERBAKOVA, V. A. LAlVDYSHEVA, M. I. AI~AlV'IlVA, V. F. VOLXOV a n d Y~. P. KUZ~ETSOVA Research Institute of Synthetic Resins Okhtinskii Chemical Combine (Received 19 October 1970)
IT ~ s b e e n s h o w n p r e v i o u s l y t h a t t h e s t r u c t u r e a n d p r o p e r t i e s of fibres f r o m m i x t u r e s of s e c o n d a r y cellulose a c e t a t e (SCA) a n d polyacrylonitrile (PAN) are d e p e n d e n t on t h e presence of a g r a f t c o p o l y m e r of these t w o p o l y m e r s [1]. Since t h e s t r u c t u r e a n d p r o p e r t i e s of fibres are largely d e p e n d e n t on t h e s t r u c t u r e a n d p r o p e r t i e s of t h e spinning solution, it was of i n t e r e s t to e x a m i n e t h e effect of t h e g r a f t c o p o l y m e r on t h e s t a t e of m i x t u r e s of solutions of cellulose a c e t a t e a n d P A N . I t is k n o w n t h a t solutions of SCA a n d P A N in d i m e t h y l f o r m a m i d e are n o t c o m p a t i b l e , w h e t h e r or n o t t h e g r a f t c o p o l y m e r is present, a n d in t i m e t h e m i x t u r e s s e p a r a t e i n t o t w o p h a s e s [2, 3]. T h e p r e s e n t p a p e r describes a s t u d y of p h a s e s e p a r a t i o n in m i x t u r e s of solutions o f SCA a n d P A N , w i t h a n d w i t h o u t g r a f t copolymer.
EXPERIMENTAL The following materials were used: 1) commercial SCA with M v : 100,000 and an acetyl content of 55'5 Yo, and degraded samples with M ~ : 80,000, 60,000 and 40,000; 2) commercial PAN with Mv:40,000, and samples prepared by radical polymerization and having My 30,000, 20,000 and 10,000; 3) SCA/PAN graft eopolymer, isolated from the product of graft copolymerization by selective dissolution of the homopolymers, the ratio of combined SCA : PAN being 40 : 60, with M~ of the grafted PAN chains equal to 180,000. The chemically pure DMF had d:0.9484 (22°), a refractive index n:1.4294 (22 °) and a boiling point of 153 °. The polymer mixtures were prepared by separately dissolving SCA, PAN and the SCA/PAN copolymer in DMF and mixing the solutions. The ratio of the polymeric components in the phases was found from the nitrogen content of the precipitated product. The composition of SCA-PAN-SCA/PAN mixtures * Vysokomol soyed. A14: No. 9, 1910-1916, 1972.