Effect of Different Molecular Weight and Concentration of Polyethylene Glycol (PEG) on Tensile and Morphology of Sago Starch Film

Abstract

Sago starch is a seasonal based plantation and widely found in Asia country. Its application mainly in cooking such as biscuits and as a thickener in jellies. To further utilise its application, bioplastic from sago starch was developed. In this study, sago starch films were prepared through a blending and casting method using polyethylene glycol (PEG) as a plasticiser by varying its molecular weights and concentrations. The interaction between starch and PEG in the blend was studied using FTIR technique. The effect on transparency, tensile stress, Young's modulus as well as elongation percentages of the films was also examined. The results suggested that the addition of low molecular weight PEG (400 g.mol-1) increased the tensile stress of sago films from 33.51 MPa up to 39.11 MPa. Nevertheless, incorporation of high molecular weight of PEG (4000 g.mol-1) decreased the tensile strength of the film. Tensile strength and elongation at break of sago films increased with increasing of PEG concentration up to 2% and decreased with further increased of PEG content. Results indicated that there was a miscibility between these two components.