University of Arkansas, Fayetteville


Rising raw material costs and shortage of woody materials necessitate alternative sources for lignocellulosic material in wood plastic composites (WPC). This study was conducted to evaluate rice hull (RH), an agricultural residue, as a cellulosic substitute in WPC. Samples were fabricated with approximately 4% zinc stearate, 48% high-density polyethylene obtained from recycled plastics and 48% lignocellulosic material by mass. The composition of the lignocellulosic material was changed from 0 to 100% RH at 20% increments while the remainder was wood flour. The extruded sampled were tested for mechanical properties such as specific gravity, water absorption, linear coefficients of thermal expansion, and strengths under compression, shear and bending. The results showed that increasing the proportions of RH to wood flour in the new composite increased the specific gravity but decreased the water absorption. The rice hull rates did not change any of the strength properties. Overall, physical and mechanical properties of the new composite was comparable to that of two of the commercial WPCs. Therefore, rice hull is a viable and renewable alternative for lignocellulosic material in WPC intended for non-structural applications such as decking, fencing, flooring and OEM.