Mechanical and moisture performance of pineapple leaf fiber/carbon fiber-eggshell reinforced epoxy composites for eco-friendly applications

This work investigates the formulation of sustainable hybrid epoxy composites reinforced with pineapple leaf fibre (PALF), an agro-waste natural fibre, carbon fibre as a synthetic reinforcement, and bio-waste eggshell powder as a filler. Six distinct laminate configurations were produced using hand lay-ups with variable proportions (0–15%) of eggshell filler. The mechanical parameters, such as tensile strength, flexural strength, impact strength, hardness, and interlaminar shear strength (ILSS), were assessed, revealing that the 10% eggshell-filled hybrid laminate exhibited superior performance, with tensile strength of 90.9 MPa, flexural strength of 166.3 MPa, and impact energy of 0.566 J. Morphological examination via SEM validated effective filler dispersion and enhanced fibre-matrix interfacial bonding. Moisture absorption studies demonstrated that higher filler content increased water uptake, with maximum absorption reaching 8.6% for L-6 in saline conditions after 10 days. These findings underscore the promise of combining plant-derived fibres, carbon fibre, and calcium-enriched biofillers to develop economical, eco-friendly composites for structural applications. The results highlight their potential in construction, transportation, and packaging industries where mechanical strength and durability in humid environments are essential.