SUPERCRITICAL CARBON DIOXIDE-ASSISTED SOLID-PHASE GRAFTING MODIFICATION METHOD FOR POLYPROPYLENE

摘要

A supercritical carbon dioxide-assisted solid-phase grafting modification method for polypropylene, comprises swelling polypropylene for 0.5 to 10 hours in supercritical carbon dioxide having dissolved vinyl monomer and an initiator, then slowly relieving the pressure; moving the polypropylene that has undergone the swelling process into a reaction kettle, and adding xylene as an interface agent, the mass of xylene being 1% of the polypropylene; increasing the temperature to between 65°C and 165°C under normal pressure, and reacting 1 to 10 hours to obtain modified polypropylene; the swelling permeation temperature during the swelling process is from 31°C to 60°C, the swelling pressure is from 7.5 to 12 MPa; the initiator is an azo compound or a peroxide. In the present method, the grafting rate reaches 5.4%, the thermal property, polarity, and mechanical property all improve substantially, and hydrophilic property is substantially enhanced.