Abstract: Styrene and maleic anhydride grafted polypropylene (PP-g-St/MAH) was prepared via a water suspension grafting process. The effect of ST dosage on the grafting reaction was investigated using melt floe rate, water contact angle, X-ray diffraction, and Fourier transform infrared spectroscopy. It showed that the graft ratio of MAH increased with increasing ST dosage. When the weight ratio of St/MAH was 3/1, the graft ratio was 3.10 % and graft efficiency reached 70.02 % With increasing grafting ratio, the MFR value decreased, melt strength increased，crystallinity lowered, and hydrophilicity enhanced.

Key words: polypropylene, styrene, maleic anhydride, grafting, water contact angle