Effect of Fiber Loading on Green Composites of Recycled HDPE Reinforced with Banana Short Fiber: Physical, Mechanical and Morphological Properties

Abstract

Currently, research on composite materials derived from natural fibers and agro-industrial waste has generated industrial proposals for producing useful materials with sufficient mechanical strength for applications involving the reuse of waste for secondary purposes. The objective of this study was to determine the influence of fiber content on the final tensile strength of the composite material, serving as a reference for the manufacture of plates. To achieve this, high-density polyethylene (HDPE) composites reinforced with short banana fibers were prepared using a blade mill and hot compression molding techniques. Two levels of short banana fiber content—10% and 20% by weight—were used, along with two types of HDPE: virgin and recycled. We evaluated the effect of adding short banana fibers on the mechanical properties of the composite, specifically tensile strength, according to the ASTM D638 standard for polymeric materials. These results were correlated with the structural properties obtained through morphological, chemical, and thermal characterization of the developed materials. The mechanical evaluation results showed that the tensile strength and elastic modulus depend on the short banana fiber content and the type of high-density polyethylene. Thermogravimetric analysis revealed that the composites decompose faster than the pure polymers (virgin and recycled HDPE). Based on these findings, the composite material prepared under optimal conditions is recommended for use in walls or construction boards where high tensile strength is not critical, due to the decreased mechanical properties resulting from the incorporation of agro-industrial waste.