Radical terpolymerization of vinyl sulfide, vinyl ether, and maleic anhydride. Evaluation of the reactivities of vinyl sulfide and vinyl ether alternative copolymerization. IV

Abstract

AbstractThe terpolymerizations of maleic anhydride (MAn), vinyl sulfide (VS) and vinyl ether (VE) initiated by α.α′‐azobisisobutyronitrile were investigated in order to evaluate the reactivities of VS and VE toward poly(MAn) radical. Since both VS and VE undergo alternative copolymerization with MAn, these terpolymerizations were approximately treated on the basis of the free propagation and complex propagation mechanisms. From the treatment of the free propagation mechanism in which only three free monomers can participate, the reactivity of the free VS toward attack of the poly(MAn) radical was found to be 4.24 to 6.63 times higher than that of free VE, and the difference in activation energy was 1.5 kcal/mole. The higher reactivity of VS than VE might be explained by the 3 d orbital resonance between the propagating radical and the adjacent sulfur atom in VS. According to the complex propagation mechanism in which only two complexed monomers can participate, the reactivity ratios of the MAn/VS and MAn/VE complex monomers were also determined. It was found that the former complex was more reactive than the latter complex toward the poly(MAn) radical.