Synthesis and radical copolymerization of trisubstituted ethylenes with styrene. 6. Alkoxy, phenoxy, and cyano ring-substituted methyl-2-cyano-3-phenyl-2-propenoates

Electrophilic trisubstituted ethylene monomers, ring-substituted methyl 2-c yano-3-phenyl-2-propenoates, RC6H4CH=C(CN) CO2CH3 (where R is 4-C2H5O, 4-C3 H7O, 4-C4H9O, 3-C6H5O, and 3-CN), were prepared and copolymerized with styr ene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and methyl cyanoacetate, and characterized by CHN elemental analysis, IR, H-1- and C-13-NMR. All the pr openoates were copolymerized with styrene (M-1) in solution with radical in itiation (AIBN) at 70 degrees C. The compositions of the copolymers were ca lculated from nitrogen analysis and the structures were analyzed by IR, H-1 - and C-13-NMR. The order of relative reactivity (1/r(1)) for the monomers is 3-CN (1.21) > 3-C6H5O (1.16) > 4-C2H5O (0.94) > 4-C3H7O (0.8305) > 4-C4H 9O (0.616). The high T-g's of the copolymers (> 130 degrees C) in compariso n with that of polystyrene indicate a substantial decrease in the chain mob ility of the copolymers due to the high dipolar character of the trisubstit uted monomer unit. Gravimetric analysis indicated that the copolymers decom pose in the range 300-400 degrees C.