Degradation of linear low density polyethylene (LLDPE) exposed to UV-irradiation

A mesophilic bacterium capable of polyethylene (PE) degradation was isolated and identified as Chryseobacterium gleum EY1. The biodegradation behavior of photo-degraded linear low density PE (LLDPE) film was investigated in compost sterilized prior to inoculation with the isolated bacterium. The LLDPE films were prepared using a minimum amount of additives such as antioxidants and neutralizing agents (the additives were added to avoid abrupt deterioration of LLDPE during the film shaping process) to exclude plausible effects of the additives on the photo-degradation behavior of LLDPE. Transition metal pro-oxidants were added to LLDPE powder, which was then molded into film. Variations in the tensile properties and molecular weight of the LLDPE films were examined as a function of UV intensity, irradiation time, and temperature. Considering the experimental results of thermo- and photo-degradation of LLDPE incorporated with Co-stearate, Mn-stearate, and Fe-stearate, the last was selected as the most desirable pro-oxidant for the photo-sensitive LLDPE films. Increasing the intensity of the UV irradiation reduced the tensile properties and molecular weight of PE–Fe (LLDPE with Fe-stearate) slightly but increased biodegradability considerably.