Effects of Rice Hull Particle Size and Content on the Mechanical Properties and Visual Appearance of Wood Plastic Composites Prepared from Poly(vinyl chloride)

This research aims to develop Wood Plastic Composites (WPCs) from rice hull and poly(vinyl chloride) (PVC). The influences of the rice hull particle size and content on the mechanical properties and the visual appearance of the WPC decking board were investigated. The experimental results revealed that the impact strength tended to decrease with increasing rice hull content. The composites with larger particle sizes exhibited higher impact strength. Under tensile and flexure load, higher rice hull content induced greater modulus and ultimate strength when the rice hull was applied at less than 60 phr. Beyond this concentration, the modulus and the strength dropped due to the formation of rice hull agglomerates. The smaller particles of the milled rice hull, the greater tendency there was for them to act as a pigment to form a darker shade close that of the rice hull on the composite decking board. The larger particle sizes were 106 μm and beyond simply embedded in the white PVC matrix.