Mechanical, thermal and water absorption properties of plasticised sago pith waste

Abstract

This paper provides an insight into the potential of utilising sago pith waste (SPW) to produce composite material. SPW is a fibrous waste that is produced as a result of the sago starch extraction process. It is made up of more than 60 % in weight of sago starch and was successfully converted into natural fibre reinforced thermoplastic starch composite using twin screw extrusion in the presence of different quantities of glycerol and water as plasticisers. No binder was added throughout the process. Good fibre-matrix compatibility was proven by SEM. Due to phase separation and fibre agglomeration, tensile strength of the composite decreased with increasing glycerol content while elongation at break remained unchanged at low values. Activation energies, Ea of the composites were computed from thermogravimetric analysis (TGA) data using Broido and Coat-Redfern equations. The obtained Ea values indicated that plasticisation led to the reduction in thermal resistance of SPW. It is suggested that blending the plasticised SPW with sago starch and polyvinyl alcohol will greatly improve upon the existing shortcomings, potentially resulting in useful consumer products from SPW, an unutilised, water polluting waste.