Novel Copolymers of Styrene and Alkyl Ring‐Substituted 2‐Phenyl‐1,1‐dicyanoethylenes

Electrophilic trisubstituted ethylene monomers, ring‐substituted 2‐phenyl‐1,1‐dicyanoethylenes, RC₆H₄CH˭C(CN)₂ (where R is 2‐methyl, 3‐methyl, 4‐methyl, 4‐ethyl, and 2,5‐dimethyl), were synthesized by piperidine catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and malononitrile, and characterized by CHN elemental analysis, IR, ¹H‐ and ¹³C‐NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (AIBN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C‐NMR, GPC, DSC, and TGA. High T_g of the copolymers, in comparison with that of polystyrene, indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 290–450°C range.

Keywords:

• trisubstituted ethylenes
• radical copolymerization
• styrene copolymers

5 Acknowledgments

We are grateful to acknowledge that the project was partly supported by the research and equipment grants from the National Science Foundation's DUE Grant (No. 9455681), Coating Industry Education Fund (CIEF), Chicago Society of Coatings Technology, the DePaul University Research and Quality of Instruction Councils, and Office of Sponsored Programs and Research.