Biodegradação de compósito de polipropileno com casca de soja em solo compostável

Abstract

The growing concern about the high demand for polymeric materials is due to their low degradation rates, which results in them persisting in nature for a long period of time, further exacerbated by improper disposal into the environment. Thus, alternatives that provide more sustainable development have become increasingly necessary. Studying possibilities to develop materials that are less harmful to the environment and can help reduce this situation is of utmost importance. An alternative to applications that consist entirely of conventional polymers is the use of natural fibers, which are abundant in the national territory, for the formulation of polymeric composites. This work proposes the reuse of soy agro-industry waste by incorporating the husk into a polypropylene matrix, produced in a single-screw extruder, aiming for the maximum possible substitution of the matrix in this processing. Biodegradation tests by mass loss were conducted for two composite formulations (polypropylene with 20% soy husk, with and without maleic anhydride) and for the matrix, at 30, 60, and 90 days. A slight decrease in the mass values of the test specimens (TSs) was observed, with a maximum reduction of 2m/m% in the biodegradable phase after 30 days of testing for the composite formulation with maleic anhydride. The presence of contaminants was evident in the optical microscopy of the TSs' surface after 90 days of biodegradation testing, which corroborated the visual analysis performed on all tested formulations. According to the results obtained in the tensile test, the presence of maleic anhydride promoted better interfacial adhesion, dispersion, and fiber distribution in the composite.