Analysis of Biodegradability of Three Biodegradable Mulching Films

The development of biodegradable mulching films is a great direction for environment protecting and oil saving problems. In this paper, it was used three kinds of biodegradable mulching films named a, b and c (different ratio between modified starch and poly-CL with pro-oxidant additives) in microorganism culture test and soil burial test was investigated under laboratory conditions. The index of degradation was assessed by visual observation, weight loss and SEM analysis from quantitative and qualitative aspect. The results of both tests showed that these biodegradable mulching films were more readily degraded than the common plastic film. The percentage weight loss was in sequence of biodegradable mulching film c > biodegradable mulching film b > biodegradable mulching film a, while common plastic film basically had no changes. Weight loss was not as obvious as the visual degradation and suggested broader types of microbial attack. SEM analysis clearly indicated that the changes of surface morphology of these samples after the soil burial exposure.