Novel Co-polymers of Vinyl Acetate and Ring-tri-substituted 2-Phenyl-1,1-dicyanoethylenes

摘要

Electrophilic tri-substituted ethylene monomers, ring-tri-substituted 2-phenyl-1,1-dicyanoethylenes, RC6H2CH=C(CN)2 (where R is 2,4,6-trimethyl, 2,3-dimethyl-4-methoxy, 2,4-dimethoxy-3-methyl, 2,3,4-trimethoxy, 2,4,5-trimethoxy, 2,4,6-trimethoxy and 3,4,5-trimethoxy), were synthesized by piperidine-catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and malononitrile, and characterized by CHN elemental analysis, IR, ~1H- and ~(13)C-NMR. Novel co-polymers of the ethylenes and vinyl acetate were prepared at equimolar monomer feed composition by solution co-polymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the co-polymers was calculated from nitrogen analysis, and the structures and properties were analyzed by IR, ~1H- and ~(13)C-NMR, GPC, DSC and TGA. The high T_g 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 tri-substituted ethylene monomer unit. Thermogravimetric analysis indicated that the co-polymers decompose in the 190-700°C range.