OXYBIODEGRADABLE POLYETHYLENE: FROM A SOLUTION TO A SECONDARY PROBLEM

Abstract

The growing use of non-biodegradable polymers, as in the production of bags, is accompanied by a problem that draws the attention of researchers, environmentalists and governments around the world: the accumulation of plastic waste in the environment. When their dimensions are smaller than 5 mm, they are called microplastics and, besides contaminating the soil, rivers and oceans, the contamination of the air by them has been investigated. An alternative to favor the degradation of olefin resins, the most widely used, is to process them with pro-oxidants that favor their abiotic degradation by thermo-oxidation and photo-oxidation, producing oxygenated fragments that can be used as nutrients by microorganisms. When processed with these additives, the polymers are called oxybiodegradable.In this work, the thermodegradation of polyethylene (PE) processed without and with two different pro-oxidants, d2wTM and benzoin, was evaluated to verify whether the presence of additives would favor oxidation or cross-linking of chains, a process that can lead to the formation of microplastics. The HDPE/LDPE films were processed by blow extrusion and exposed in an oven at 58°C with forced air circulation. Characterization was done by viscosimetry, FTIR, TGA and SEM. The results indicated that the PE underwent cross-linking, more evident in the additivated films. Cross-link formation was higher for the film processed with d2wTM, followed by the film with benzoin. Thus, under the conditions used, oxybiodegradable PE films suffer cross- linking and what would be a solution to the problem of accumulation of plastic waste would become a secondary problem, the formation of microplastics.