Polyacrylonitrile resins with high molecular weight were obtained by ternary copolymerization of acrylonitrile, itaconic acid and methyl acrylate in dimethyl sulfoxide at low temperature using 2,2 -azobis(2,4-dimethylvaleronitrile) as initiator. Orthogonal design method was employed to investigate the effect of the polymerization temperature, the concentrations of the initiator and the comonomers on the molecular weight and the conversions of the comonomers, and thus the optimized formula was achieved. The copolymer was characterized by FT-IR, NMR and GPC. The results showed that the low polymerization temperature and feeding of the initiator and the high concentration of the comonomers would all benefit in increasing the molecular weight of the copolymer, and the concentration of the initiator is the most important factor to influence the molecular weight of the copolymer.

Key words: acrylonitrile, 2,2 -azobis(2,4-dimethylvaleronitrile), low-temperature solution copolymerization