The bulk free radical copolymerization of styrene and maleic anhydride

The composition of copolymer depended on the concentration of initiator in the bulk free radical polymerization of styrene (St) and maleic anhydride (MA) at 70°C. In low concentration of initiator the composition of copolymer had nothing to do with the content of monomer in the feed. However, in high concentration of initiator the product of polymerization contained polystyrene and random copolymer. Homopolymerization of styrene took place when copolymerization stopped at lower conversion. At the same time, copolymer tended to 1 : 1 alternation with the increasing of content of MA in the feed in the range of 70∼160°C. The experimental results indicated that the two sorts of polymerization simultaneously existed if temperature was over 120°C. The conversion of copolymerization had less dependence on the temperature and were less than 50%. The composition of copolymers tended to 1 : 1 alternation as the temperature approached 140°C. The random copolymers of St and MA were yielded above 140°C.