Studies on mechanical and water absorption behavior of biofiber-reinforced epoxy biocomposites added with seashell, eggshell, and coconut biofillers

The present study emphasizes the mechanical characteristics and water uptake behavior of seashell, eggshell, and coconut fillers added with sisal, kenaf, and pineapple leaf fiber-reinforced epoxy composites. The present study compares the difference in mechanical performance between filler-based composites with only fiber-based composites. The weight proportion of fillers and fiber reinforcement collectively were 30% by weight, and epoxy was 70% by weight in all prepared specimens. According to the results of the experimental findings, the inclusion of biofillers with fiber and hybridization of fibers gives a reduction in void content as sisal/epoxy/seashell composite shows a minimum 2.09% void content than other specimens. Hybrid pineapple/sisal/kenaf/epoxy composite absorbs minimum water content during the water immersion test. Kenaf/epoxy/seashell composite exhibits a maximum tensile strength of 72.25 MPa, and kenaf/epoxy/eggshell composite achieved a maximum value of tensile modulus at 30.49 GPa as compared to other developed composite specimens. While flexural strength was maximum for sisal/epoxy/eggshell composite at 257.25 MPa, flexural modulus was maximum for kenaf/epoxy/eggshell composite at 68.4 MPa. Sisal/epoxy/coconut composite achieved a maximum impact strength of 0.9 J as compared to all developed composite specimens. Scan electron microscopy (SEM) reveals the mechanism of fiber/matrix debonding, fiber fracture, and fracture of matrix after mechanical testing.