Biodegradation of Polyethylene-Octene Elastomer-Starch Composites in Soil

This study investigated the biodegradation of POE/starch and POE-g-MAH/starch composites in a natural soil environment for 6 months. Nonbiodegradable polyethylene-octene elastomer (POE) and its graft copolymer POE-g-MAH were blended with gelatinized waxy corn starch (GWCS) in different proportions. The weight loss, morphology and mechanical properties of the blend films were measured every month. Pure POE and POE-g-MAH specimens did not lose weight, while tensile strength and elongation at break only slightly changed in the soil, which indicated that pure POE and POE-g-MAH did not degrade in soil. With increasing starch content, the weight loss, tensile strength and elongation at break of POE/starch and POE-g-MAH/starch blend films reduced, as well as with increasing soil burial time, due to the biodegradation of starch. SEM photographs showed more holes and cracks with increasing starch content and burial time. The weight loss of the blends reduced evidently in the first 3 months, but much slower in the latter. Also, POE-g-MAH/starch blends showed better biodegradation than POE/starch blends.