Effect of water absorption on mechanical properties of hemp fibre/polyolefin’s composites

Abstract

The main objective of this research was to study the effect of water absorption on mechanical properties of hemp fibre reinforcement for polyolefin’s (PP & HDPE) composites. The poor resistance towards water absorption is one of the drawbacks of natural fibres which make it more important. Hemp fibre-polyolefin’s (PP & HDPE) composites were subjected to water immersion tests in order to study the effects of water absorption on the mechanical properties. Composites specimens containing 20% and 30% fibre weight were prepared. Water absorption tests were conducted by immersion specimens in a plastic container with normal tap water at room temperature for different time durations. The tensile, flexural and impact properties of dry and water immersion composite specimens were investigated. The percentage of moisture uptake increased as the fibre loading increased due to the high cellulose content. In order to improve compatibility of the natural hemp fibre and polyolefin’s matrix, two commercial malamaleated polypropylene and polyethylene were used. The tensile, flexural and impact properties of hemp fibre/polyolefin’s (PP & HDPE) composite specimens were found to increased with compatibilizer. The dry and water immersion specimens of the PP composites was shows better mechanical properties. The better understanding between fibre and matrix interface were investigated by Scanning Electron Microscopy