Flexural and Impact Properties of Recycled High-Density Polyethylene (rHDPE) Composites Reinforced With Hybrid Jute and Banana Fibers

Abstract

Hybrid jute–banana fiber-reinforced recycled high-density polyethylene (rHDPE) composites present a sustainable alternative for achieving improved mechanical performance and ecological durability. This study addresses the challenge of simultaneously optimizing flexural and impact properties along with structural integrity by employing a novel (0°/90°/0°/90°) stacking configuration using both plasma-treated and untreated fiber preforms. Composites were fabricated through compression molding, placing rHDPE sheets strategically within a four-layer fiber stack and applying 5-ton pressure at 160°C for 15 min, followed by a 24-h curing period. Plasma treatment drastically influenced the adhesion of fiber and matrix, leading to an increased impact strength and altered behavior of water absorption. The greatest impact strength of 31.86 kJ/m²—a 45.4% improvement over its untreated counterpart—was found in the plasma-treated hybrid composite (plasma jute–banana composite [PJBC]) with a 7.6% flexural strain, signifying improved energy dissipation and ductility. However, flexural strength in hybrid composites decreased marginally (from 21.3 to 20.3 MPa) due to increased surface brittleness. Plasma treatment improved water absorption in jute composites (0.13%) via increased porosity, but hybridization minimized the effect to yield balanced moisture absorption and mechanical properties. The synergistic combination of jute stiffness and banana flexibility in hybrid form, with plasma-induced surface activation, resulted in composites with optimal structural integrity and sustainability. These findings demonstrate the viability of plasma-treated hybrid rHDPE composites for resource-efficient application in packaging, automotive, and construction sectors, in line with the goal of the circular economy.