Manufacturing Technique and Interfacial Modification of Polypropylene/Short Glass Fiber Composites

Maleic anhydride grafted polypropylene (PP-g-MA) is used as a coupling agent, and the influence of its used amount on the mechanical properties of the polypropylene/short glass fiber (PP/SGF) composites is examined. 1, 2, and 3 wt% of PP-g-MA is separately added to PP/SGF composites that are made at an 80/20 ratio (wt%), made into pellets on a single screw extruder, and then made into test samples on an injection machine. When PP-g-MA increases from 1 wt% to 3 wt%, the tensile strength of the PP/SGF composites increases from 56.22 MPa to 64.85 MPa; likewise, flexural strength increases from 67.29 MPa to 81.24 MPa, and Izod impact strength increases from 197.70 J/m 269.61 J/m. SEM images show that the surface of SGF are encapsulated with a layer of PP matrix, which indicates that PP-g-MA can effectively improve the interfacial adhesion between PP and SGF and thus increase the mechanical properties of the resulting composites.