Estudo da degradação de blendas contendo materiais biodegradáveis em solo controlado.

Abstract

Synthetic polymer’ production and consumption have been growing since their invention, along with their inappropriate disposal and accumulation in the environment. One of the ways to reduce contamination caused by incorrect disposal would be the development of biodegradable blends. In this work, polymer blends (BPs) of high-density polyethylene (HDPE) and polystyrene (PS) were used, all containing thermoplastic starch (TPS) as a biodegradable phase. Two groups of BPs, one with HDPE and the other with PS were prepared with different carboxylic acids from natural and biodegradable sources as compatibilizers (stearic, myristic and palmitic acids) and the same phase ratio (60/40), a group with the same compatibilizer and variations in the proportions of phases (20/80, 40/60, 60/40 and 80/20) and another group with the same compatibilizer, both with HDPE phase, one with the phase extruded once and the other extruded three times. The blends were prepared in the laboratory and the specimens were injected using an injection molding machine. The degradation tests were carried out in a controlled environment using soil prepared following international standards for the study of polymer degradation (ASMT G-160) for 35 months. Morphological analyzes were performed using SEM and chemical analyzes using FT-IR. The results show that the samples lost an amount of mass equivalent to the amount of TPS contained in the blend, indicating that only the TPS phase was degraded. The HDPE blends with the highest concentration of TPS had greater mass loss reaching 80% in the blend containing 80% of TPS in weight. The data indicate that the greatest influence on mass loss is the amount of TPS present in the blend.