Highly Filled Polypropylene Rubber Wood Flour Composites

Abstract

In this research, polypropylene composites filled with Hevea Brasilliensis wood flour at filler content up to 60 wt% were prepared and investigated in order to determine the effects of polymer melt flow rate (MFR), number of reprocessing times, filler size, and filler content on thermal and mechanical properties. The results reveal that the composites of polypropylene with higher melt flow rate (lower viscosity) provided greater values of flexural and tensile properties. The study additionally exhibits the recyclability potential without losing mechanical properties. Furthermore, both flexural and tensile modulus increased, while both flexural and tensile strength decreased with increasing wood flour contents. In addition, the average particle size of wood flour that was suitable for improving the mechanical properties was approximately 200-300 μm. In the last section of the research, the effects of maleic anhydride grafted polypropylene (MAPP) coupling agent were investigated. It is worth noting that, the flexural strength and tensile strength of highly filled composites with MAPP at 5 wt% (based on wood flour) were approximately 110% and 87% higher than those of the composites without MAPP, respectively. In the presence of coupling agent, the enhancement of interfacial adhesion was analyzed using scanning electron microscope (SEM).