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 (