Chemical modification of cassava starch for degradable polyethylene sheets

Cassava starch was chemically modified by radiation grafting with acrylic acid to obtain cassava starch graft poly(acrylic acid), which was further modified by esterification and etherification with poly(ethylene glycol) 4000 and propylene oxide, respectively. The modified product was characterized by NMR spectroscopy and contact angle measurement. The blends of LDPE with EBS wax had properties similar to the LDPE: blends with the modified starch in terms of surface wettability, tensile properties, and hardness, but with a much better degradation in soil due to the much higher water absorption. This article describes the chemical modifications of hydrophilic cassava starch to become partially hydrophobic, which was then used for blending with LDPE sheets for evaluations of mechanical, thermal and degradation properties. (C) 2001 Elsevier Science Ltd. All rights reserved.