Characterization study on mechanical, wear, and water absorption properties of stacking ordered natural kenaf/sisal fiber and cellulose particle reinforced epoxy biocomposite

The present study focuses on the economic and environmental potential of developing sustainable epoxy composites reinforced with silane-treated Luffa cylindrica fibers and Dimocarpus longan shell powder. Utilizing these low-cost, renewable agro-waste materials not only reduces production costs but also promotes eco-friendly alternatives to synthetic reinforcements. The incorporation of fibers and fillers substantially enhanced the composite’s performance, with specimen RFF2 achieving the highest mechanical strength—tensile (139 MPa), flexural (163 MPa), and impact (6.1 J)—owing to uniform filler dispersion and improved interfacial bonding via silane treatment. Superior wear resistance was observed in RFF3, due to better dispersion of filler particle in to the matrix composite. However, the slightly higher water absorption (0.042%) in RFF3 resulted from additional hydrophilic sites and microvoids. Scanning electron microscopy (SEM) revealed key failure modes, including fiber pull-out in RF, brittle fracture in RFF1, strong fiber–matrix adhesion in RFF2, and filler agglomeration in RFF3. Overall, the results demonstrate that synergistic reinforcement with Luffa cylindrica fibers and Dimocarpus longan shell powder offers an economical, environmentally sustainable route to fabricating high-performance epoxy composites.