Mechanical, wear, and fatigue behavior of alkali-silane-treated areca fiber, RHA biochar, and cardanol oil-toughened epoxy biocomposite

This research investigated the role of adding bio toughener and reinforcements in the process of making biocomposite for sustainable engineering applications. The primary aim of this study was to develop a biocomposite material using agricultural waste and validate the performance of the composite prepared. The areca fiber was procured from a fiber firm, while the rice husk ash (RHA) biochar and cardanol oil (CO) were prepared by low-temperature pyrolysis and Soxhlet extraction respectively. The areca fiber was surface-treated by alkali-silane through hydrolysis process. The biocomposites were prepared using hand the layup method, followed by curing at elevated temperature. The composites underwent testing as per the American Society for Testing and Materials (ASTM) standards. According to the mechanical properties, the addition of cardinal oil to the resin improved the toughening effect along with areca fiber and biochar. Highest tensile strength of 208 MPa, flexural strength of 236 MPa, and Izod impact toughness of 7.2 J were noted for composite designation NC3. The wear properties of cardanol oil-toughened epoxy resin composites showed a downtrend; however, further addition of biochar particle of 1 vol.% improved the coefficient of friction (COF) and sp. wear rate. Similarly, the fatigue behavior of composite designation NC3 showed the highest life counts of 50,622 for 50% of ultimate tensile stress (UTS) at 3 Hz. The scanning electron microscope (SEM) fractograph images revealed improved adhesion for fiber to resin and the trace for toughness improvement. These high toughness epoxy biocomposites made using agricultural waste-derived reinforcements could be sustainable, cost-effective, and environment-friendly and used as an alternate material in structural, defense, automotive, and drone applications.