Hybrid hemp fiber–silicon carbide reinforced epoxy composites: Enhancing mechanical strength and moisture resistance for sustainable applications

• Hybrid reinforcement of hemp fiber and silicon carbide (SiC) significantly enhances the mechanical performance and moisture resistance of epoxy composites. • Optimized formulation (30 wt.% hemp fiber + 6 wt.% SiC) achieved the highest tensile (39.4 MPa) and flexural (57.4 MPa) strengths, along with the lowest water absorption (2.63%). • Chemical treatment of natural fibers and controlled filler dispersion improve fiber–matrix interfacial bonding, confirmed by SEM analysis. • Hand lay-up and compression molding techniques , combined with ASTM-standard testing, validate the composites’ suitability for lightweight structural and automotive applications. This study explores the mechanical and water absorption behavior of hemp fiber-reinforced epoxy composites modified with varying weight percentages (2%, 4%, and 6%) of silicon carbide (SiC) filler. The novelty of this research lies in its systematic investigation of the synergistic effects of both natural fiber and ceramic filler on enhancing the structural and environmental performance of biocomposites. This combination remains underexplored in the current literature. The primary aim is to determine the optimal hybrid formulation that balances strength, durability, and moisture resistance for eco-friendly structural applications. Hemp fibers were chemically treated to improve interfacial bonding, and five composite formulations were fabricated via the hand lay-up technique followed by compression molding. Mechanical tests, including tensile, flexural, impact, and hardness tests, as well as water absorption analysis, were conducted by ASTM standards. The results revealed that incorporating SiC substantially enhanced mechanical properties and reduced moisture uptake. Notably, the composite containing 30 wt.% hemp fiber and 6 wt.% SiC exhibited the highest tensile strength (39.4 MPa), flexural strength (57.4 MPa), impact strength (6.3 kJ/m²), and Shore D hardness (79.3), while also demonstrating the lowest water absorption (2.63%). Scanning electron microscopy confirmed improved filler dispersion and fiber–matrix adhesion in this formulation. Conversely, reduced fiber content or excessive filler led to agglomeration and suboptimal performance. These findings confirm the potential of hemp–SiC–epoxy composites as lightweight, high-performance, and sustainable alternatives for structural and automotive applications, promoting the use of renewable resources in advanced engineering materials.