Studies on biodegradability, morphology and thermomechanical properties ofLDPE/modified starch blends

Starch was converted to a hydrophobic derivative by phthalation. The starch phthalate (stath) thus obtained was found to show highly crystalline natur e and sharp melting point. The potential of stath as a substitute for starc h in the development of biodegradable blends was investigated. Blends of LD PE containing up to 30% starch were prepared and the latter was gradually r eplaced by stath. It was observed that the tensile strength and elongation at break increased while the modulus decreased as the starch was substitute d by stath. Morphology of binary LDPE/stath blends showed improved adhesion leading to enhanced mechanical properties compared to LDPE/starch blends. DSC analysis showed no significant change in the T-m of LDPE by incorporati on of 30% stath in spite of a wide difference in the T-m of the two compone nts. Biodegradation of starch was found to decrease on esterification. Howe ver, the LDPE/stath blends showed greater degradation in soil compared to L DPE/starch blends. (C) 2000 Elsevier Science Ltd. All rights reserved.