Injection moulded all-polypropylene composites composed of polypropylene fibre and polypropylene based thermoplastic elastomer

Abstract All-polypropylene composites comprising of polypropylene based thermoplastic elastomer (TPE) matrix and polypropylene homopolymer (hPP) fibre reinforcement were prepared and processed by injection moulding. For the injection moulding of plaque specimens pre-impregnated pellets, prepared by combined filament winding and film stacking were used. The processing–structure–property relationships of the all-PP composites were studied on specimens cut from the plaques produced at different melt temperatures (120, 140, 160 °C). The properties determined covered the moulding-induced shrinkage, flexural stiffness via dynamic mechanical analysis, static tensile and high-speed perforation impact behaviours. It was demonstrated that by using TPE as matrix the processing window of this novel all-PP composite could be significantly increased. The static tests demonstrated that the yield stress and tensile modulus of the all-PP composites were prominently increased. Optical micrographs taken from polished sections of the composites confirmed good interfacial adhesion between the matrix and the fibres. It was established that the shrinkage behaviour of the TPE based all-polypropylene composites is similar to that of conventional polypropylene.