Mechanical Properties and Water Absorption Behaviour of Chopped Rice Husk Filled Polypropylene Composites

Abstract

The reinforcing effect of chopped rice husk (CRH) into polypropylene has been studied. Composites containing different amounts of CRH with 0 to 40 parts per hundred part of polymer (php) were prepared using a co-rotating twin screw extruder and characterized by mechanical properties and also water absorption. In order to increase the interphase adhesion, polypropylene grafted with maleic anhydride was added as a coupling agent to all the composites studied. It was found that the tensile and flexural modulus of the composites containing 40 php of CRH increased approximately by 33% and 100%, respectively. The results also showed that while flexural strength was moderately improved by increasing of CRH into the matrix, elongation-at-break and energy-at-break decreased dramatically. A reasonable adhesion between the main components was also observed by examining the scanning electron micrographs. Water absorption experiments showed that although the diffusion coefficient increased with CRH loading, all the composites followed case I diffusion.