Evaluation of the physical-chemical degradation of biodegradable plastics sold in supermarkets.

Abstract

The present investigation proposed to evaluate the degradability of plastic materials declared publicly as biodegradable plastics. Its physical and mechanical properties were determined. Likewise, the materials were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Two plastics declared as biodegradable (TA and TB) and a conventional plastic such as Polyethylene (TC) were selected, which were subjected to different environments such as water, soil and weather, the study was carried out for a period of 4 months. It was determined that the biodegradable plastic TA presented a greater weight loss when subjected to soil and water, while TB and TC did not present significant changes in these media. The TB sample presented the greatest weight loss when exposed to the elements. When subjected to mechanical tests, it was observed that the TA samples showed a greater decrease in the properties of maximum resistance and deformation. This behavior was corroborated with SEM, where TA was the one that showed the most signs of degradation when exposed to different media, TB plastic, despite being sold as a biodegradable material, showed slight changes in its morphology like TC plastic. While the FTIR analysis revealed slight variations in their peaks and in the absorbances of the regions corresponding to the biodegradable molecules.