Novel copolymers of trisubstituted ethylenes and styrene- 5. Ring-disubstituted methyl 2-cyano-3-phenyl-2-propenoates

Electrophilic trisubstituted ethylenes, ring-disubstituted methyl 2-cyano-3-phenyl-2-propenoates, RCH=C(CN)CO2CH3 (where R = 2,3-dichlorophenyl, 2,4-dichlorophenyl, 2,6-dichlorophenyl, 3,4-dichlorophenyl, 4-chloro-3-nitrophenyl, 5-chloro-2-nitrophenyl, 2-chloro-6-fluoro), were prepared and characterized. All the propenoates, except methyl 2-cyano-3-(4-chloro-3-nitrophenyl)-2-propenoate, were copolymerized with styrene (M1) in solution with radical initiation (AIBN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, 1H-, and 13C-NMR. The order of relative reactivity (1/r1) for the monomers is 2,4-dichloro (2.1) = 3,4-dichloro (2.1) > 2,6-dichloro (0.8) = 2,3-dichloro (0.8) > 2-chloro-6-fluoro (0.6) > 5-chloro-2-nitro (0.2). The high glass transition temperatures of the copolymers (> 190°C) in comparison with that of polystyrene indicate a substantial decrease in the chain mobility of the copolymers due to the high dipolar character of the trisubstituted monomer unit. Gravimetric analysis indicated that the copolymers decompose in the range 300-400°C.