AbstractThe polymerization of acrylonitrile and methyl methacrylate initiated by polyvinylamine‐copper(II) chelate was studied in dimethylsulfoxide solution, in the presence and absence of carbon tetrachloride. For comparison, the dimeric chelate(1,3‐diaminopropane‐copper(II) chelate) was also chosen as an initiator. The initiation activity of the dimeric chelate was found to be higher than that of the polymeric chelate in dimethylsulfoxide solution, different from the cases in aqueous media. The dimeric chelate could initiate the polymerization of acrylonitrile effectively, even in the absence of carbon tetrachl