Enhancing mechanical properties of natural fiber composites: a study on the effects of fiber loading and filler addition

In this research, we conducted an extensive analysis of two distinct composite materials: NWBF/EP (nonwoven banana fiber/epoxy) and NWBF/EP/WNP (nonwoven banana fiber/epoxy with walnut powder). These composites were meticulously engineered, utilizing epoxy as the matrix, nonwoven banana fiber as the primary reinforcement, and walnut powder as the secondary reinforcement. Our investigation unveiled that the NWBF/EP/WNP hybrid composite exhibits superior mechanical properties in comparison to the NWBF/EP composite. Notably, the BW4 hybrid composite demonstrated a substantial increase in tensile strength, reaching an impressive 76.7 MPa. This enhancement underscores the potential for augmenting composite stiffness by elevating the WNP ratio up to a specific threshold, though exceeding this threshold leads to a reduction in epoxy resin content. Furthermore, our study revealed substantial improvements in flexural strength as WNP was introduced, with a noteworthy 5.8% rise at a 5% weight percent WNP loading. The pinnacle of flexural strength, 43.6 MPa, was achieved at a 20% weight percent loading. Impact toughness also displayed significant improvements, with the highest impact strength (5.2 J) observed in BW3. This highlights the potential for enhancing the toughness of the hybrid composite within a defined WNP weight percent range. We also gained valuable insights into hardness, void fraction, and the influence of walnut powder. The addition of walnut powder increased void fraction, reduced density, and enhanced various mechanical properties. Our evaluation of wear performance emphasized the pivotal role of factors such as sliding velocity, fiber content, sliding distance, and normal load. In conclusion, this research not only elucidates the mechanical advantages of the NWBF/WNP/epoxy hybrid composite but also offers critical insights for potential applications. The findings underscore the potential of these hybrid composites to serve as sustainable and competitive alternatives to synthetic fiber products in a range of engineering and manufacturing contexts.