Moisture adsorption and absorption behaviour of bio-fiber filled thermoplastic composites

Abstract

Hydrophilic nature of ligno-cellulosic fibers can affect dimensional stability and interfacial bond strength of wood polymer composites. In this paper, moisture adsorption and absorption behaviour of bio-fiber filled high density polyethylene composites has been reported. Composites were prepared with wood pulp and bamboo flour at varying filler concentration and subjected to moisture adsorption and absorption. The magnitude of moisture absorption and adsorption increased with increasing filler content. Moisture adsorption in wood fiber based composites was higher than bamboo flour but there was no significant difference in their water absorption behaviour. Use of coupling agent exhibited a significant influence on the magnitude of water absorption by the composites. Composites with coupling agent absorbed 25–40 % less moisture as compared to the composites without coupling agent in both filler types. Moisture absorption behaviour in the composites was explained based on the theoretical Fickcian diffusion model.