MORPHOLOGY CONTROL IN POLYPROPYLENE GRAFT COPOLYMERS

摘要

A graft copolymer comprising a backbone of a propylene polymer material having a vinyl monomer graft polymerized thereto is produced by (1) treating a p ropylene polymer material with a free radical polymerization initiator, (2) treating the propylene polymer material with at least one grafting monomer capable of being polymerized by free radicals, in the presence of a polymerization rate modifier, and (3) removing an y unreacted grafting monomer from the graft copolymerized propylene polymer material, decomp osing any unreacted initiator, and deactivating any residual free radicals in the mate rial. Use of the polymerization rate modifier increases the polymerization induction time on the polymer surface, consequently facilitating monomer diffusion into the interior o f the polymer particles so that surface polymerization of the monomer is inhibited.