Investigation on mechanical properties of the green synthesis bamboo fiber/eggshell/coconut shell powder-based hybrid biocomposites under NaOH conditions

This research delves into the effects of different alkalization treatment approaches on the mechanical characteristics of epoxy matrix composites that are reinforced with natural bamboo fibers and enriched with egg and coconut shell powders as fillers. Various weight ratios of fibers and fillers were investigated, specifically at 5%, 10%, 15%, 20%, 25%, and 30%. The study assessed mechanical properties such as tensile strength, flexural behavior, microhardness, and impact resilience. Findings indicate that composites with alkali-treated fibers demonstrate superior mechanical performance (49.28 MPa of tensile, 57.33 MPa of flexural 89 HV of hardness, and 1.3 kJ·m−2 of impact) compared to untreated counterparts. Particularly noteworthy is the significant improvement in fracture toughness observed with the inclusion of 20% hybrid laminates, surpassing the performance of existing biomaterial-based composites. This heightened toughness is attributed to the optimized composition of fibers and enhanced water absorption capabilities. Conversely, the incorporation of 25% and 30% hybrid composites led to a decrease in mechanical strength (38.65 MPa of tensile, 46.7 MPa of flexural, 72 HV of hardness, and 1.19 kJ·m−2 of impact) due to the formation of additional interfacial contacts, pores, and voids within the polymeric matrix.