Abiotic Oxidation Studies of Oxo-biodegradable Polyethylene

The best approach to induce oxo-biodegradation in polyethylene is the use of special additives known as prooxidants. Pro-oxidants accelerate abiotic oxidation and subsequent polymer chain cleavage rendering the product apparently more susceptible to biodegradation. In this work, the abiotic oxidation is studied to understand how the addition of nanoclay affects the oxidation rate and the degradation mechanism of oxo-biodegradable polyethylene. In order to achieve this, the following materials were used in this study: (1) polyethylene (PE), (2) oxo-biodegradable polyethylene (OPE), (3) polyethylene nanocomposite (PE-Nac), and (4) oxo-biodegradable polyethylene nanocomposite (OPENac). Wide-Angle X-ray scattering (WAXS) and Transmission Electron Microscopy (TEM) studies reveal that grafting in the preparation of composites helps to achieve mixed intercalated/exfoliated morphology in PENac and OPENac. Abiotic oxidation was carried out in an oven for a period of 14 days at 70 degrees C with air supply. The effect of abiotic oxidation was evaluated by measuring the changes in tensile strength, elongation at break, carbonyl index and molecular weight. Results show that OPE and OPENac are more susceptible to oxidation than PENac. The molecular weight distribution data obtained from GPC reveal that the addition of nanoclay does not alter the oxidation mechanism in OPE significantly.