Interfacial engineering of pepper and glass fiber-reinforced palm oil–toughened epoxy hybrid biocomposites: mechanical, thermal, and morphological characterization

This work investigates the mechanical, thermal, and morphological aspects of epoxy hybrid biocomposites reinforced with glass and pepper fibers and modified with palm oil for enhanced toughness. Composites with varying fiber loading (10, 20, and 30 weight percentage (wt%)) were prepared at a fixed palm oil concentration of 20 wt%. The resulting specimens were evaluated through tensile, impact, water absorption, and thermal conductivity tests to determine the effects of synthetic, natural, and hybrid fiber reinforcing on composite performance. The outcome revealed that the fiber accumulation notably enhanced the properties of the epoxy matrix. The glass fiber composite G20 showed excellent mechanical performance with tensile strength, elongation at break, and impact strength values of 39.7 MPa, 13.2%, and 2.4 J/m2 respectively. The pepper fiber composite P20 illustrates the highest tensile strength of 34.7 MPa. Hybrid composites combine the reinforcing contribution of glass fibers with the potential sustainability benefits of pepper fibers. Thermal conductivity decreased as the pepper fiber content increased, indicating improved thermal insulation. Morphological studies confirmed the uniform dispersion and improved interfacial adhesion of fibers in the modified composites, suggesting their potential for lightweight structural and engineering applications.