Evaluation of degradability of biodegradable polyethylene (PE)

Thermo-oxidative degradation of polyethylene films containing pro-oxidant has been studied at three temperatures that normally occur during composting conditions. Besides temperature, oxygen concentration was also varied. After various periods, the effects of thermo-oxidation were evaluated by measurements of molecular mass of the materials. It is shown that while temperature is the most important factor influencing the rate of thermo-oxidative degradation of the materials, oxygen concentration is of negligible importance. The investigation has also shown that when the material is degraded into low molecular mass products, it is bioassimilated. The rate of aerobic biodegradation of the oxidation products was evaluated under controlled composting conditions using measurements of produced carbon dioxide. The degree of bioassimilation in our case was about 60%, and still increasing, after 180 days. (C) 2003 Elsevier Science Ltd. All rights reserved.