Environmental biodegradation of polyethylene

Abstract

The degradation of a commercial environmentally degradable polyethylene was investigated in two stages. Firstly by abiotic oxidation in an air oven to simulate the effect of the compost environment and secondly in the presence of selected microorganisms. Initial biofilm formation was followed by fluorescence microscopy and the subsequent growth of bacteria on the surface of the plastic was observed by scanning electron microscopy (SEM). It was observed that microbial growth occurred on the presence of PE samples that had been compression moulded to thick sections but had not been deliberately pre-oxidised. Molecular enlargement and broadening of molecular weight distribution occurred after preheating in air at 60 °C but not at ambient temperatures but colonisation of microorganisms occurred on all samples. Erosion of the film surface was observed in the vicinity of the microorganisms and the decay of oxidation products in the surface of the polymer film was measured by FTIR measurements and was found to be associated with the formation of protein and polysaccharides, attributable to the growth of the microorganisms.