A new method for preparing anhydride grafted polypropylene with high grafting ratio by combining microwave reaction and reactive extrusion

Maleic anhydride grafted polypropylene (PP-g-MAH) is an effective compatibilizer in the preparation of polypropylene composites. Its grafting ratio plays an important role in the dispersion of filler or blend in polypropylene (PP) matrix resin, but the grafting ratio of PP-g-MAH prepared by reactive extrusion is low. A method for preparing PP-g-MAH with high grafting ratio and low odor was proposed by combining microwave reaction and melt extrusion. The grafting ratio of the PP-g-MAH products obtained by this method without the assistance of comonomer reached 1.95%. The results of melt index and rheology showed that the crosslinking occurred during the preparation process, thus avoiding the large reduction of molecular weight of PP. Meanwhile, the problem of odor was avoided because no comonomer was added during the process. The application results showed that PP-g-MAH prepared by this method improves the compatibility of glass fiber (GF) and PP, thus improving the mechanical properties of polypropylene/glass fiber (PP/GF) composites. This work explored a novel way to prepare PP-g-MAH with high grafting ratio.