Method for preparing polypropylene toughening modifier by irradiation grafting

The invention discloses a method for preparing a polypropylene toughening modifier by irradiation grafting, which comprises the following steps: mixing polypropylene, polyethylene, ethylene-octylene copolymer (POE) and an antioxidant in percentage by weight, carrying out melt extrusion on a screw extruder, cooling, granulating, drying, adding the granules into a packaging bag, and carrying out gamma-ray irradiation to obtain the irradiation-grafted polypropylene toughening modifier. After the product is blended with an isotactic polypropylene resin, the normal-temperature/low-temperature impact strength of the isotactic polypropylene is obviously enhanced, the normal-temperature impact strength of the modified polypropylene is enhanced by 53.5-60%, the low-temperature impact strength is enhanced by 45.2-50%, the crystallization temperature of the polypropylene modified product is enhanced by 3.4-5.7 DEG C, and the crystallization rate is increased. The polypropylene toughening modifier can enhance the degree of crystallinity of the isotactic polypropylene, refine the crystal grains, reduce the phenomenon of secondary crystallization in the later storage process and eliminate the residual internal stress in the polypropylene modified product. The polypropylene toughening modifier is widely used for producing extrusion, injection molding and foaming products of polypropylene.