Alternating Copolymerization and Copolymers of Styrene and N-(2,4-Dibromoplienyl)maleimide

Free radical copolymerization of styrene (St) and AT-(2,4-dibromo- phenyllmaleimide (DBPMI) in dioxane solution gave an alternating copolymer in all proportions of feed comonomer compositions. The copolymerization reactivity ratios were found to be rx = 0.049 ± 0.0023 (St) and r2 = 0.0115 ± 0.0018 (DBPMI); Q and e values were also calculated. The molecular weights of the copolymers obtained are relatively high and the alternating copolymer had a glass transition temperature of 507 K: the thermal stability of the copolymer is higher than that of polystyrene. The equilibrium constant of charge-transfer complex of St and DBPMI was determined by \u27H-NMR spectroscopy in deuterated chloroform and gave a value of 0.12 L/mol. The initial rate of copolymerization was measured as a function of the monomer ratios, and the participation of the charge-transfer complex monomer and the free monomers was quantitatively estimated. It was established that the copolymerization of St with DBPMI proceeds predominasntly through participation of the free monomers