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Effect of reaction medium on radical copolymerization of acrylonitrile with vinyl acids
Author(s) -
Bajaj Pushpa,
Sreekumar T. V.,
Sen Kushal
Publication year - 2000
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/1097-4628(20010228)79:9<1640::aid-app140>3.0.co;2-7
Subject(s) - acrylonitrile , itaconic acid , polymer chemistry , azobisisobutyronitrile , methacrylic acid , polymerization , copolymer , chemistry , polyacrylonitrile , radical polymerization , monomer , nuclear chemistry , polymer , organic chemistry
Radical polymerization of acrylonitrile (AN) with methacrylic acid (MAA) and itaconic acid (IA) was carried out in a mixture of dimethylformamide (DMF) and water at 70°C using α, α′‐azobisisobutyronitrile (AIBN) as an initiator. Monomer feed in the polymerization vessel was 98:2 (AN:MAA/IA) in the molar ratio, and the DMF:H 2 O ratio was varied between 20:80 and 80:20 (w/w). Copolymers were characterized by FTIR, carbon, hydrogen, nitrogen elemental CHN analysis, 1 H‐ and 13 C‐NMR, and viscometry. The rate of polymerization ( R p ) was found to decrease with an increase in DMF concentration in the reaction medium, that is, in 20% DMF for AN–MAA system, the R p is 1.23% min −1 in 1 h of polymerization, while in 80% DMF, R p is reduced to 0.37% min −1 . The nature of the vinyl acid also affects the R p . It has been shown that the rate of polymerization is higher for an AN–MAA system as compared to an AN–IA system ( R p = 1.0% min −1 ) and the methacrylic or itaconic acid content in the copolymer increases with an increase in the DMF concentration. The MAA content in the poly(AN–MAA) polymer produced in 20% DMF is 3.2 mol %, which increases to 6.1 mol % (calculated through FTIR spectra) when DMF is increased to 80% in the reaction medium. The intrinsic viscosity [η] of the poly(AN–IA) and poly(AN–MAA) copolymers in DMF was found to be in the range of 0.67–2.90 dLg −1 depending on the reaction medium. In determining the intrinsic viscosity, a definite deviation from rectilinearity of the concentration dependence in the high‐dilution region is observed, thereby demonstrating the polyelectrolyte behavior of these polymers. Through FTIR and NMR spectral studies, PAN homopolymer and other copolymers have shown the formation of a small quantity of acrylamide units. In addition copolymer P 10 , which contains 10.1 mol % IA, has shown anhydride formation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1640–1652, 2001