Development of alumina (Al2O3) filler loaded cotton-glass fiber reinforced hybrid composite: Comparative study of mechanical and water absorption performance for sustainable structural applications

To achieve a sustainable solution, herein, the study combined recycled cotton fibers with glass fibers and reinforced them with Al 2 O 3 ceramic fillers to produce high-performance epoxy composites, reducing reliance on synthetic fibers. Four composites systems, cotton fiber epoxy (CFRC), glass fiber epoxy (GFRC), cotton-glass hybrid epoxy (HFRC), and Al 2 O 3 -filled hybrid epoxy (HFRCA), were fabricated through hand lay-up process followed by compression molding. Mechanical testing, water absorption analysis, and microstructural characterization were performed. CFRC exhibited the lowest performance due to poor fiber-matrix adhesion and significant porosity, whereas GFRC showed better tensile (81.64 MPa) and flexural strength (161.54 MPa). The hybrid composite without Al 2 O 3 filler exhibited improved performance, however, remained inferior as compared to GFRC. Incorporation of Al 2 O 3 filler achieved optimum performance, significantly enhancing tensile and impact energy. Moreover, HFRCA exhibited the highest flexural strength (170.75 MPa), compared with the others, with an enhanced fiber-matrix adhesion and a reduced degree of voids. All composites exhibited extremely low water absorption (<1.7%), with hybridization and Al 2 O 3 addition further reducing uptake. ANOVA and Tukey’s HSD confirmed significant differences among composites. Overall, the findings demonstrated that HFRCA with optimum performance is sustainable, durable, and can be effectively utilized in structural applications in the aerospace and automotive sectors.