Hybrid natural fiber composites based on cashew apple bagasse and mahogany fruit for multifunctional performance

This study investigates the mechanical and acoustic properties of hybrid composites developed from Cashew Apple Bagasse (CAB) fibers and a Mahogany Tree Fruit Filler (MFF) reinforced with an epoxy matrix. In this study, the effect of NaOH treatment (5 % and 10 %) on CAB fibers at different MFF weight fractions (0–25 wt %) was studied. The results demonstrate that the composites treated with 5 % NaOH and had 15-20 wt% MFF showed the best results. It exhibited a 40 % increase in tensile strength, a 50 % increase in flexural strength, a 45.71 % increase in impact strength, and a 56.67 % increase in the noise reduction coefficient (NRC) compared to the untreated samples. These improvements can be attributed to the removal of surface impurities on the fiber surface, improved fiber-matrix bonding, and dispersion of the filler in the matrix. Using sodium hydroxide (NaOH) beyond the threshold value (10 %) with a high filler content (>20 wt %) made the fibers to break down and clump together, which decreased its mechanical and acoustic performance. The combination of CAB and MFF in a hybrid composite showed the best synergetic approach, striking a good balance between reinforcement and load transfer efficiency. These composites can be used in car interior, soundproof panels, and lightweight structures.