Development and Fabrication of Polymer Matrix Composites Reinforced with Coconut Fibre and Calabash Ash

The pursuit of lightweight, sustainable, and high-performance materials has intensified within modern automotive engineering, particularly as environmental concerns surrounding petroleum-based polymers continue to escalate. This study investigates the development and fabrication of a polymer matrix composite reinforced with coconut fibre and calabash ash as a hybrid bio-based reinforcement system. The research sought to evaluate how the combined incorporation of lignocellulosic fibre and agricultural waste ash influences key mechanical and physical properties relevant to automotive interior applications. A Box Behnken experimental design was employed to optimize three processing variables: coconut fibre content, calabash ash particulate content, and epoxy to hardener ratio. Composite samples were fabricated using treated coconut fibres and processed calabash ash within an epoxy matrix, followed by characterization through hardness, impact toughness, porosity, and water absorption tests. Statistical analysis using response surface methodology and ANOVA revealed that an epoxy to hardener ratio of 9.5:1.5 with 4% coconut fibre and 7% calabash ash produced the most balanced performance, yielding hardness of 53.874 BHN, toughness of 6.172 J, low porosity (1.168%), and minimal water absorption (1.323%). These findings confirm that hybrid reinforcement significantly enhances structural integrity while maintaining moisture resistance. The study demonstrates the viability of coconut fibre and calabash ash composites as sustainable alternatives for lightweight automotive components and recommends further investigation into thermal durability and large-scale manufacturing applications.