Propriedades mecânicas de compósitos de poliestireno reforçado com celulose de bagaço de cana

Abstract

The EPS (expanded polystyrene) is a polymer resulting from the polymerization of styrene in water and is greatly used in package manufacturing. Because of that, the entire world produced a large quantity of these residues. Meanwhile, another important agro residue is the sugarcane bagasse, because of the massive sugar and ethanol production in Brazil. Thereby, this work will propose an application of these residues, combining its properties in a single product, a composite. The pulping process in a strongly alkaline medium (NaOH) extracted the cellulosic fibers from sugarcane bagasse, resulting in cellulose fibers with residual lignin. Fibers (10 and 20% by weight) and PS were mixed by extrusion in a single-screw extruder, followed by double-screw, and then injection molding. The natural fiber composites was evaluated by tensile, flexural and hardness mechanical properties. The surface of fractured composites was analyzed by scanning electron microscopy (SEM). As a result, the addition of 20 % wt of fibers to polystyrene improves the flexural, tensile and hardness properties in respect to recycled PS. This result indicates best stress transference of fibers to matrix due to the interface interaction promoted by residual lignin, which actuates as coupling agent.