Mechanical, thermal, and tribological improvement of jute fiber–epoxy composites using fish scale biochar

Abstract This study investigates the effectiveness of fish scale biochar as a sustainable micro-filler for enhancing the mechanical, thermal, and tribological performance of jute fiber–reinforced epoxy composites. Six composite formulations were developed by varying the biochar content from 0 to 10 wt.% while maintaining a constant jute fiber loading of 45 wt.%. The incorporation of biochar significantly improved the composite properties, with the 4 wt.% formulation (JF-FSB4) exhibiting the highest tensile strength (61.48 MPa), flexural strength (100.63 MPa), interlaminar shear strength (20.47 MPa), tensile modulus (3.69 GPa), flexural modulus (4.65 GPa), impact strength (13.72 J), and hardness (76.58). Wear resistance increased progressively up to 6 wt.% biochar due to improved surface integrity and enhanced load-bearing capability, whereas higher filler levels resulted in performance reduction attributed to particle agglomeration. Water absorption decreased to a minimum of 2.98 % for the JF-FSB6 composite, indicating enhanced moisture resistance. Thermal conductivity increased steadily from 0.24 to 0.39 W/m·K with increasing filler content, driven by the formation of conductive carbonaceous pathways. Overall, the results demonstrate that fish scale biochar serves as an effective eco-friendly filler capable of improving mechanical stability, thermal performance, and wear resistance, making these composites suitable for lightweight engineering applications.