Influence of Saltwater and Distilled Water on the Mechanical Properties of Natural Fiber–reinforced Polyester Composites Enhanced with SiC Nanoparticles

This study examines the mechanics of polyester composites reinforced with Cyperus and Calotropis gigantea fibers, together with their moisture absorption characteristics. The ability of distilled water and salt water to absorb moisture was studied. The subsequent composites undergo tensile and flexural testing: one reinforced with pure calotropis gigantea fiber, one with pure cyperus fiber, and one with a hybrid of both fibers. The examination examines the alterations in mechanical properties resulting from varying moisture conditions. The impact of silicon carbide (SiC) nanoparticles on these composites is also assessed. The results indicate that SiC nanoparticles enhance the mechanical properties, particularly in damp conditions. Examining fracture behavior facilitates the understanding of the interactions of natural fibers, the matrix, and nano-reinforcement. The CF composite exhibits a moisture absorption of 8.19% in distilled water and 9.50% in saltwater at a maximum natural fiber weight fraction of 40%, while the CGF composite demonstrates maximum absorptions of 6.57% and 8.26%, respectively. Comparable conditions produce outcomes of 4.19% and 6.54% for the hybrid composite. The incorporation of silicon carbide into the polymer matrix significantly diminishes the moisture absorption capacity of the cyperus composite to 35.2% for distilled water and 31.7% for saltwater, in contrast to the cyperus fiber-reinforced composite. Overall, the study demonstrates that SiC nanoparticles effectively mitigate moisture-induced degradation in natural fiber composites, making them promising candidates for outdoor, marine, and structural applications.