Green composites using recycled plastic bags and pineapple fibers waste

Abstract

This study proposes that green composites using recycled plastic bags (PEr) extruded with pineapple fiber waste (PR) from a juice industry to increase pineapple’s economic value stimulate practices that prioritize recycling and development of new materials. PEr composites were prepared using PR as a filler, using different fiber loadings of 5, 10, and 15 wt%, and the use of a coupling agent, prepared via extrusion and injection molding. The samples were investigated by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis, inflammability, mechanical tests (tensile, impact, and shore hardness), scanning electron microscopy, and water absorption tests. FTIR results demonstrated that the addition of PR to the PEr caused a decrease in the characteristic bands of neat PEr, evidencing the chemical interactions. Thermal analysis showed that the addition PR decreased composites' thermal stability, causing relatively higher percentages of char compared to neat PEr, which increased the burning rate of composites, except for PEr/15PR and PEr/5PR-C. Green composites exhibited higher tensile modulus and hardness than PEr, but the impact tests presented a decrease in the fibers' addition to the PEr due to the reduction of toughness and resilience. SEM of fractured surface composites presented microcracks, voids, and fibers breakage in the interface. The composites showed low water absorption (up to 0.804%). The coupling agent’s use presented a low influence on the mechanical and thermal properties and a slight decrease in water absorption. These results demonstrate o potential of the reuse of plastic bags and industrial waste for green composites.