Novel Copolymers of Styrene. 4. Halophenoxy Ring-Substituted 2-Cyano-3-phenyl-2-propenamides

Novel electrophilic trisubstituted ethylenes, halophenoxy ring substituted 2-cyano-3-phenyl-2-propenamides, RC₆H₄CH?C(CN)CONH₂,where R is 4-(4-bromophenoxy), 2-(4-chlorophenoxy), 3-(4-chlorophenoxy), 4-(3-chlorophenoxy), 4-(4-chlorophenoxy), and 4-(4-fluorophenoxy) were prepared and copolymerized with styrene. The monomers were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and cyanoacetamide, 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 in the presence of a radical initiator, 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, GPC, DSC, and TGA. Thus, the order of relative reactivity (1/r₁) is 4-(4-ClC₆H₄O) (2.01) > 4-(4-FC₆H₄O) (0.89) > 4-(4-BrC₆H₄O) (0.73) > 3-(4-ClC₆H₄O) (0.65) > 2-(4-ClC₆H₄O) (0.24) > 4-(3-ClC₆H₄O) (0.22). 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. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (10.4–15.0 wt%), which then decomposed in the 500-800°C range.