Influência da granulometria da fibra de sisal no desempenho de compósitos híbridos de PEADr/argila bentonita/sisal

Abstract

The thermoplastic polymer industry has made significant progress in recent years in seeking alternatives to minimize the environmental problems generated by these materials. One of the alternatives is the production of composite materials from recycled polymers and plant fibers. Polyethylene is one of the materials that constitutes a large volume of polymeric waste, while sisal fiber has been widely used as reinforcement in plastics in recent times. Thus, in this study, hybrid composites of recycled polymer matrix (HDPE), bentonite clay and sisal fibers in different sizes were obtained. The sisal fiber was processed, including grinding and sieving, to obtain some particle size distributions, with four variations being used: 2.000mm, 0.840mm, 0.590mm and 0.180mm. All materials (HDPE/Bentonite/Sisal) were oven dried before being used in the processing. The HDPE/Bentonite/Sisal composite materials were processed in a twin-screw extruder and were subsequently characterized by the techniques of Density, Shore D Hardness, Water Absorption, Impact, VICAT and HDT. The percentage of composite materials used in processing was in the proportion of: 70% recycled HDPE, 10% bentonite clay and 20% sisal. In general, the presence of sisal fiber caused a reduction in the impact resistance of all composites obtained. On the other hand, the presence of sisal fiber provided an increase in hardness, density and water absorption of all composites obtained when compared to HDPEr. The presence of sisal fiber and clay did not influence the softening temperature (VICAT), nor the heat deflection temperature (HDT) of the composites, as the results found from these two tests showed values very close to those of PEADr, with no difference significant among the materials studied.