Microwave-aided fabrication of natural fiber hybrid composites: A synergistic approach to mechanical,wear,and computational property analysis

Abstract

This study examines HDPE (High Density Polyethylene) based hybrid composites reinforced with natural fibers (ramie and kenaf) fabricated by an energy-efficient microwave-assisted molding method. Alkali-treated natural fibers were utilized to fabricate composites with optimum microwave power and processing time of 600 W and 720 ± 30 s, respectively. Mechanical tests showed notable improvements compared to pure HDPE, comprising a 24.1% augmentation in tensile strength (24.2 ± 1.3 MPa), a 10.6% increase in Shore D hardness (59.2 ± 2.5), a 32.3% enhancement in flexural strength (18.3 ± 0.9 MPa), and a 28.5% rise in impact strength (23.6 ± 1.4 kJ/m²). Wear experiments indicated that wear and specific wear rate (S_WR) escalated with sliding speed, load, and duration. HDPE exhibited increased wear and deformation, particularly at a sliding speed of 3 m/s with a normal load of 30 N. The hybrid composite demonstrated superior wear resistance, with negligible S_WR increases at lower loads (10–20 N) at moderate velocities. Friction studies showed reduced and uniform friction forces for the hybrid composite, whereas HDPE experienced 50% higher friction forces accompanied by thermal softening and adhesive wear. Scanning electron micrographs demonstrated a wear progression from mild adhesive at 1 m/s to severe abrasive and thermal wear at 3 m/s. The HDPE matrix underwent substantial degradation, whereas natural fibers enhanced load-bearing capability, enhancing composite stability and tribological performance. The Mori-Tanaka and Double Inclusion models estimated Young's modulus for the hybrid composites within 10% of experimental values, indicating their precision in assessing natural fiber-reinforced composites.