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

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.
Keywords- Starch, plastics, biodegradable, polyethylene.