Search

Equimolar alternating copolymers of vinyl acetate and electrophilic trisubstituted ethylene monomers, halogen ring‐disubstituted methyl (E)‐2‐cyano‐3‐phenyl‐2‐propenoates, RC 6 H 3 CH&dbnd;C(CN)CO 2 CH 3 (where R=2,3‐dichloro, 2,4‐dichloro, 2,6‐dichloro, 3,4‐dichloro, 3,5‐dichloro, 2,4‐difluoro, 2,5‐difluoro, 2,6‐difluoro, and 3,4‐difluoro) were prepared via copolymerization in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, 1 H‐ and 13 C‐NMR. High glass transition temperatures of the copolymers in comparison with that of polyvinyl acetate indicate a decrease in chain mobility of the copolymers due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the decomposition of the copolymers occurs in two steps. The first step is relatively fast weight loss in 272–370°C range followed by very slow decomposition of the formed residue in 370–950°C range. [ABSTRACT FROM AUTHOR]

Electrophilic trisubstituted ethylene monomers, ring-substituted methyl 2-cyano-3-phenyl2-propenoates, RC6H4CH=C(CN)CO2 CH3 (where R = H, 2-CH3, 3-CH3, 4-CH3, 2-C2H5, 4-C2H5, 4-iC3H7, 4-C4H9 and 2,4,6-(CH3)3), were synthesized by the piperidine-catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and methyl cyanoacetate, and characterized by CHN elemental analysis, IR, 1H- and 13C-NMR. Co-polymerization of the propenoates and vinyl acetate in solution with radical initiation (AIBN) at 70°C yielded equimolar alternating co-polymers. The composition of the co-polymers was calculated from nitrogen analysis and the structures were analyzed by IR, 1H- and 13C-NMR, GPC, DSC and TGA. The high Tg of the co-polymers in comparison with that of polyvinyl acetate indicates a substantial decrease in chain mobility of the co-polymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the co-polymers decompose in the 214–400°C range. [ABSTRACT FROM AUTHOR]