Radiation‐induced ionic polymerization at low temperature

Abstract

Abstract The copolymerization, by means of ionizing radiation, of acrylonitrile with styrene or methyl methacrylate was investigated at ‐78°C. in bulk and in various solvents. The copolymerization proceeds by a cationic mechanism in methylene chloride solution, by a free radical mechanism in bulk, and by both an anionic mechanism and a free radical mechanism in dimethyl formamide, diethylamine, toluene, and ethyl bromide solutions. The rate of anionic polymerization of acrylonitrile increases with dilution of monomer. The cationic polymerization in methylene chloride solution was shown to be caused by the catalytic action of hydrogen chloride which is formed from the irradiation of chlorinated hydrocarbon. It was concluded that the main factor in the induction of an anionic polymerization of acrylonitrile is the large reactivity of the monomer in anionic polymerization.