Produção de compósitos sustentáveis usando resíduos lignocelulósicos e polietileno verde.

Abstract

Lignocellulosic waste, when generated in a sustainable way, can be transformed into energy products, deconstructed back to building blocks to generate new materials with high added value or used as reinforcement agents in composite materials, since these wastes are produced in large quantities. Thus, the present study aimed to make composites with green polyethylene and lignocellulosic residues. For this, sawdust from Pinus Elliottii wood and pecan nutshell were used. Six types of composites were produced with different proportions of the aforementioned materials, and part of the lignocellulosic residues were subjected to a thermal treatment at 180 ± 2 ºC for 2 hours, in order to change the chemical structure of the raw materials, aiming to improve the interaction between the aforementioned residues and green polyethylene. Subsequently, the materials were homogenized and molded by flat pressing at a temperature of 175 ºC. Starting from the molds, samples were made to be submitted to density, flexural and tensile strength, Shore D hardness, SEM, DMA, TGA, FTIR, equilibrium moisture content, thickness swelling, water absorption and wettability tests. The main results showed that the heat treatment of the raw materials was not a determinant factor for the water absorption and swelling in thickness, as well as for the flexural strength. However, it caused a reduction in the equilibrium moisture content, smaller contact angles, impact on traction and densities above 0.97 g/cm³. Overall, the generated materials could be used as structural WPCs.