Interface engineering of areca sheath fiber reinforced epoxy biocomposites using silane-functionalized pistachio shell biochar for lightweight engineering applications

Natural fibre-reinforced polymer composites are increasingly explored for lightweight structural applications due to their environmental compatibility and low density; however, their mechanical and tribological performance requires further improvement. In this study, alkali-treated areca sheath fibre-reinforced epoxy composites containing 0–4 vol.% silane-treated pistachio shell biochar were fabricated using hand lay-up followed by compression moulding. The composite properties were evaluated through mechanical, physical, thermal, tribological, and morphological investigations. The composite containing 2 vol.% biochar (ASB2) exhibited optimum performance, with tensile strength increasing from 51.84 to 72.18 MPa, flexural strength from 81.45 to 108.74 MPa, impact strength from 3.36 to 4.32 J, and shear strength from 17.96 to 25.06 MPa. Hardness increased from 80.92 to 91.76 Shore D, while water absorption decreased from 5.82 % to 4.21 %. Thermal conductivity decreased from 0.284 to 0.241 W m −1 K −1 . Wear loss and coefficient of friction also decreased, indicating improved tribological performance. One-way ANOVA confirmed statistically significant effects of biochar content on all investigated physical, mechanical, and thermal properties, with F-values ranging from 153.20 to 850.30 and p < 0.001. These findings demonstrate the potential of pistachio shell biochar as a sustainable functional filler for lightweight and wear-resistant composite applications.