EFFECTS OF INJECTION PRESSURE ON THE MICROSTRUCTURES AND MECHANICAL PROPERTIES OF SHORT GLASS FIBER INJECTION-MOULDED REINFORCED POLYPROPYLENE

The paper reported the effects of short glass fiber(GF) content and injection pressure on the microstructures and mechanical properties of GF/PP composites.Experimental results showed that the tensile strength was improved, but the impact strength, break elongation and melt flow rate (MFR) decreased with increasing of glass fiber content in GF/PP composites.Orientation degree of GF in core layer was promoted with increase of injection pressure, but the orientation degree of GF in skin layer was parallel to the melt flow direction(MFD) by metallographic optical microscopy and SEM.The crystalizing ability of polypropylene in GF/PP composite went down with increase of GF content by polarization microscopy.