Degradation in soil and monitoring of chemical-physical changes in biodegradable polymeric systems

Plastic items (mulch films, irrigation tubes, etc.) are widely used in agriculture, with mulching films being the dominant category. End-of-life options for agricultural plastic waste represent a big issue. In the last decades, the solid-waste management associated to the growing use in agricultural field of plastic materials has stimulated increasing interest in oxo- and biodegradable polymers. To convert a waste into a resource, both oxo- and biodegradable polymers for agricultural use have been developed and introduced into the market. Recently, oxo-degradable based plastics were banned from the EU market. In agricultural field, to date biodegradable polymers are commercially used exclusively for mulching films. Thus, several research activities are being carried out to broaden their applications. In the last year, we have investigated the degradation in soil of biodegradable polymers, blends, and composites. I will provide an overview of the studies focused on aliphatic polyesteramides, irrigation tubes based on Bio-Flex® and Mater-Bi®, as well as mulching films, before and after photo-oxidation, PBAT/CaCO3 nanocomposites, and biobased polyurethanes. The degradation behavior of the biodegradable polymeric systems was compared with that of traditional polyolefins or oxo-degradable polyethylene. The chemical-physical changes induced by soil degradation in biodegradable system, the combined influence of UV-irradiation, the effect of nanofillers, the degradation mechanism in biobased polyurethanes will be highlighted. Overall, our aim is to provide new criteria to evaluate the performance of biodegradable films in agriculture, before and after lifetime, underlining the advantages of new materials on the soil burial degradation. The need will be accounted for further studies addressed to establish a correspondence between accelerated weathering and degradation in real environmental conditions.