Properties of octanoated starch and its blends with polyethylene.

Octanoated starch (OCST) was prepared by esterification of native starch with octanoyl chloride. The new material was characterised by H-1 NMR, FTIR, and elemental analysis. This showed that the esterification had proceeded to a degree of substitution of 2.7. The octanoated starch was subsequently mixed with low density polyethylene (LDPE) at various proportions in a Haake Rheomixer. Similar blends of LDPE were also prepared with plasticised starch (PLST) for comparison purposes. The thermomechanical properties were determined as a function of blend composition. The prepared LDPE/OCST blends show better mechanical properties compared to their respective LDPE/PLST blends. In particular, the elongation at breaking is significantly higher in the LDPE/OCST blends. The latter exhibit also a higher thermal stability and a low water absorption. Copyright (C) 1997 Elsevier Science Ltd. All rights reserved.