Mechanical Characterization of Epoxy Composites Reinforced with a Blend of Hibiscus rosa and Snake Grass Fibers Enhanced with Neem Gum Powder

Abstract

Mechanical and physical characteristics were studied of epoxy composites reinforced with different blends of the Hibiscus (H) rosa plant fiber and snake (S) grass fiber, with and without the addition of neem gum powder. The incorporation of the snake grass fiber significantly enhanced the mechanical properties, with the biocomposite 20S10H exhibiting the highest tensile strength (56 MPa), flexural strength (87 MPa), hardness (86 SD), and impact strength (6.98 J), due to the synergistic effect of snake grass fiber and neem gum as a binder. The interlaminar shear strength also showed an improvement, reaching a maximum of 6.52 MPa for the biocomposite 20S10H, reflecting enhanced interfacial bonding and reduced void content. Water absorption (40%) decreased with the increased proportion of snake grass fiber and the inclusion of neem gum, with the lowest absorption recorded for the biocomposite 30S30H, indicating reduced moisture uptake. In contrast, biocomposites with a higher proportion of Hibiscus rosa fiber exhibited higher water absorption. The scanning electron microscopy (SEM) study of the fracture surfaces demonstrated enhanced fiber-matrix adhesion and decreased porosity in biocomposites with neem gum, validating the neem gum’s contribution to better interfacial bonding and overall biocomposite efficacy.