Grafted copolymerization of N-phenylmaleimide and styrene in porous polyvinyl chloride particles suspended in aqueous solution.

N-phenylmaleimide (N-PMI) and its precursor, (Z)-4-oxo-4-(phenylamino)but-2-enoic acid, were synthesized from aniline and maleic anhydride. Copolymerization between N-phenylmaleimide and styrene was initiated in micropores and outside surface of porous polyvinyl chloride (PVC) resin suspended in aqueous phase. The modified PVC was characterized with Gel Permeation Chromatography, thermal gravimetric analysis and scanning electron microscopy. The result of high performance liquid chromatography shows that the purity of N-PMI reached 97.3%. Thermal gravimetric analysis indicated that the introduction of N-PMI could clearly affect the thermal degradation behavior of PVC, and when PMI was at 6.25% of the PVC mass, the decomposition temperature T0.5 of modified polymer was increased to 314.2°C. The glass transition temperature of modified polymer was increased from 70°C to 80°C.