Reactivity ratios for copolymerization with the participation of a charge-transfer complex

The complexation between styrene (St) and N-phenylmaleimide (PMI) was inves tigated by H-1-NMR spectroscopy, and the existence of a complex was proved. The equilibrium constant of St/PMI in chloroform at 50 degrees C was deter mined to be 0.27. New elementary propagation reactions were proposed. On th e basis of the propagation elementary reactions for copolymerization with t he participation of a charge-transfer complex (CTC), a method for measuring the reactivity ratios is presented. Four reactivity ratios and relative re activities of free monomer and CTC were obtained. They are r(12) = 0.034, r (21) = 0.012, r(1C) = 0.0030, r(2C) = 0.0034, and k(1C)/k(12) = 11.34, k(2C )/k(21) = 3.42.