Interface-engineered jute/sisal fibers and silicon nitride nanoparticle reinforced epoxy composites: mechanical, tribological, and thermal performance

Natural fiber–based hybrid composites have gained increasing attention due to their sustainability, low density, and potential to replace synthetic reinforcements in engineering applications. However, their wider adoption is limited by inadequate interfacial bonding and inferior wear and thermal performance. In this context, the present study aims to enhance the performance of jute/sisal fiber reinforced epoxy composites through the incorporation of silicon nitride (Si 3 N 4 ) nanoparticles. Hybrid composites containing 15 wt.% jute and 15 wt.% sisal fibers with varying Si 3 N 4 content (0–4 wt.%) were fabricated using a hand lay-up technique. The composites were evaluated for hardness, impact, tensile, flexural, shear, wear, and thermal conductivity properties, supported by scanning electron microscopy. The results revealed a systematic improvement in mechanical and tribological properties with increasing Si 3 N 4 content up to 3 wt.%, where the composite exhibited maximum tensile strength (55.85 MPa), flexural strength (84.67 MPa), reduced wear rate, and lower coefficient of friction. SEM analysis confirmed uniform nanoparticle dispersion, improved fiber–matrix adhesion, and effective crack suppression. The findings demonstrate that Si 3 N 4 -filled jute/sisal/epoxy hybrid composites offer a promising, eco-friendly solution for lightweight structural and tribological applications.