Preparation of Modified PP-g-MAH with High Melting Point and High Crystallinity Based on Friedel-Crafts Reaction of Chlorinated Polypropylene

This study proposes a novel strategy for preparing maleic anhydride-grafted polypropylene (PP-g-MAH) with high crystallinity and high grafting content. Using highly crystalline low-chlorinated chlorinated polypropylene (LC-CPP) as the starting material, the reactive carbon-chlorine bonds were exploited to graft toluene onto the polypropylene backbone via the classic Friedel-Crafts reaction, yielding arylated polypropylene. Leveraging the facile formation of benzylic radicals, the copolymerization of maleic anhydride (MAH) and styrene (St) was subsequently initiated under mild conditions, successfully affording modified PP-g-MAH with a maximum MAH grafting content of up to 10.5%, a high melting point and high crystallinity (melting point of 152.4 ℃, crystallinity of 30.67%).This approach effectively addresses the issues of low grafting efficiency and compromised chain regularity associated with conventional melt-grafting methods, thereby paving the way for high-performance applications of polypropylene.