Synergistic Effects of Layup Sequence and Walnut Shell Powder on Physico‐Mechanical and Thermal Characteristics of Areca and Kenaf Fiber Reinforced Epoxy Composites

This research investigates the physical, mechanical, and thermal properties of epoxy composites reinforced with areca and kenaf mats, exploring their behavior both with and without the incorporation of walnut shell powder (WSP). Areca/kenaf hybrid composites were fabricated with 20 wt% fiber content using different layup sequences (AKAK, AKKA, and KAAK) and WSP was incorporated at concentrations of 2.5, 5, 7.5, and 10 wt%. The physical, mechanical, and thermal properties of areca/kenaf fiber mat reinforced epoxy composites were investigated under specified layup sequences and filler percentages, following ASTM standard testing procedures. The composite properties are improved by incorporating WSP filler into the areca/kenaf fiber reinforced epoxy composite, with an optimal filler content of 7.5 wt%. The highest tensile strength (61.84 MPa) and flexural strength (93.62 MPa) were attained by the KAAK layup sequence at 7.5 wt% WSP loading, followed by a reduction at higher filler percentages. The incorporation of WSP filler yields substantial improvements over unfilled composites, including 24.64% enhanced impact energy and 13% increased surface hardness. Scanning electron microscopy (SEM) analysis provides further confirmation, demonstrating strong interfacial adhesion between the reinforcement and the epoxy matrix.