Behaviour in soil of polyethylene film and polyethylene film additivated with starch

The ever increasing use of plastic films for the manufacture of commonly used objects, and, therefore, their increasing presence in municipal solid waste, has, in recent years, made biodegradability a useful characteristic for these products. This study investigates films designated biodegradable and examines their actual capacity to biodegrade on burial in soil. The films tested were polyethylene and polyethylene with starch based additives and fatty acids to promote biodegradation. The samples were subjected to the action of microorganisms in soil in two ways: under strictly controlled laboratory conditions, and exposed to normal atmospheric conditions. The results cover 7 and 12 months of tests and underline the greater importance of physical agents (light) than biological ones in the degradation process.