Interfacial properties of polypropylene fibre-matrix composites

A novel composite consisting of polypropylene fibres (PP) in a random poly (propylene-co-ethylene) (PPE) has been prepared and its properties evaluated. The matrix and fibre components retained their separate melting temperatures. The melting temperature of the polypropylene fibres increased after formation of the composites. The compression moulding of the composites at a temperature below the melting temperature of the fibres caused annealing of the fibre crystals. The mechanical properties of the all PP composites were measured and it was found that by incorporation of long PP fibres into a PPE matrix the flexural and tensile modulus increased. The adhesion between the PPE matrix and PP fibres in the PP composite was characterized using a micro-bond test inspired by the fibre pull out technique. The results show that the adhesion was remarkably increased when polypropylene fibres were substituted for glass fibres in a polypropylene matrix. Nevertheless the thermal processing conditions of the composite materials cause a large reduction in the mechanical behavior of the reinforcement.