Produção de embalagens biodegradáveis usando biocompósito de matriz polimérica e reforçadas com fibras lignocelulósicas de resíduos vegetais

Abstract

Global population growth has significantly increased the production of urban solid waste. In low-income countries like Mozambique, around 56% of waste consists of food and vegetable matter, causing environmental harm when improperly disposed of. The use of single-use plastics, such as expanded polystyrene (EPS), commonly used in fast food packaging, further exacerbates pollution due to its low biodegradability. In this context, the valorization of fibrous plant waste for biodegradable packaging emerges as a promising alternative. This study aimed to produce biodegradable packaging using cassava starch-based biocomposites reinforced with lignocellulosic fibers from sugarcane bagasse, corn straw, and elephant grass. Initially, the biocomposites were produced in sheet form with different geometries through manual molding. They were then evaluated to select those with properties closest to EPS, based on formulations of cassava starch and sugarcane bagasse, subsequently incorporating 10% to 30% of the other fibers. The biocomposites exhibited densities between 0.263 and 0.320 g/cm3 and a yellowish coloration. Optical micrographs showed good fiber distribution in the corn straw formulations, while those with elephant grass showed less uniform distribution due to incompatibility with starch and sugarcane bagasse. All biocomposites demonstrated higher water absorption compared to EPS, especially those containing elephant grass. The addition of sugarcane bagasse and corn straw fibers provided rigidity and structural integrity to the starch matrix. Due to the high NO2 emission levels (approximately 2.5 ppm), composting of these biocomposite residues is recommended to utilize nitrogen in biofertilizer production. Packaging prototypes were made with starch, sugarcane bagasse, and corn straw, as they displayed properties most similar to EPS. The results indicate that lignocellulosic plant waste fibers hold substantial potential for use in biodegradable packaging production.