Study of the biodegradability behavior in films of starch with added rice-dust vs. films of Polylactic acid with corn starch in a controlled composting system

Abstract

Nowadays, plastics and oil derivatives are easier access and low-cost, which is why plastic is present everywhere. However, this trend has caused real damage to the environment due to the prolonged life span of plastics which cause accumulation. Therefore, alternatives to the use of plastic have been studied, being one of the solutions is the use of natural biopolymers. As a result, exists in the market different alternatives, i.e., biodegradables, biodegradables-compostable, oxo-biodegradables, etc. Nevertheless, it is still necessary to study their biodegradability; thus, this study aims to analyze different biopolymers' biodegradation at 25 °C (room temperature) under controlled composting conditions. For this effect, three polysaccharide base matrices (films) were made by casting varying the content of their constituents, i.e., plantain starch (AP) + cassava starch (AY) + gelatin (G) using glycerol as a plasticizer and adding up to 10% of fiber (rice-dust)-P, and compared with a commercial matrix made of Polylactic acid (PLA) and corn starch (AM). All the films were subjected to weight control and speed of biodegradation for 28 days. Additionally, the water solubility of all the films was evaluated and characterized using infrared spectrometry-FTIR. All the films made by casting showed similar behavior, being noticeable their affinity with the topsoil used for the composting. Importantly, the film with high fiber (10%), N9, presents lower water solubility, less biodegradability, and weight loss. On the other hand, the commercial films (PLA + AM) showed changes until day 7 of the composting assay, then stabilizing until the last day of the assay (day 28).