Biodegradability of degradable mulching film in a laboratory-controlled composting test

A series of degradable films was prepared, and 2 formulas of polyethylene (PE) films with the highest degradable performance were experimentally determined. These films contained 3.43% and 0.44% stearate, and were denoted as PE-3 and PE-4, respectively. Their biodegradability was studied in a laboratory-controlled composting test using ordinary PE film (OPEF) as a control. Contrast composting experiments indicated that the biodegradability of untreated samples was very low, and that the biodegradation rates of PE films after natural aging were significantly higher. FT-IR analysis showed that OPEF changed little after the composting experiment, and that PE-3 and PE-4 showed a carbonyl absorption peak at 1720 cm^{-1}, whose intensity increased with increased composting time. Analysis of the viscometric-average molecular weight revealed that it changed little for untreated film but significantly decreased for aged films, especially PE-3, after the composting experiments.