Effect of macromolecular coupling agent on the property of PP/GF composites

Silane-grafted polypropylene manufactured by a reactive grafting process wa s used as the coupling agent in polypropylene/glass-fiber composites to imp rove the interaction of the interfacial regions. Polypropylene reinforced w ith 30% by weight of short glass fibers was injection-molded and the mechan ical behaviors were investigated. The results indicate that the mechanical properties (tensile strength, tensile modulus, flexural strength, flexural modulus, and Izod impact strength) of the composite increased remarkably as compared with the noncoupled glass fiber/polypropylene, SEM of the fractur e surfaces of the coupled composites shows a good adhesion at the fiber/mat rix interface: The fibers are coated with matrix polymer, and a matrix tran sition region exists near the fibers. (C) 1999 John Wiley & Sons, Inc.