The effect of hybrid filler loading on mechanical and physical properties of Epoxy Bio-Composite

The aim of study was to investigate the mechanical and physical properties of natural hybrid fillers reinforced epoxy composite. Hybrids fillers used in this study were kenaf bast fibers and rice husk. Particulate rice husks were treated with 10% NaOH solution while kenaf bast fibers were treated with 3 wt% of vinyltriethoxysilane in order to improve the adhesion bonding between natural fillers and epoxy matrix. The fillers and matrix were prepared at 5 levels of fillers ratio between kenaf bast fibers and rice husks (10:0, 10:10, 5:15, 3:17 and 0:40). All composites were fabricated using hand lay-up techniques. Mechanical and physical performance of hybrid composites were evaluated and studied. The results revealed that tensile strength of hybrid composite increased from 9.54 MPa to 12.91 MPa while flexural strength of hybrid composites showed increment from 10.86 MPa to 13.11 MPa as kenaf bast fiber loading increased in the hybrid composition. However pure epoxy exhibited higher tensile and flexural strength, 33.44 MPa and 27.75 MPa, respectively compared to those of the hybrid composites. This was mainly due to weak adhesion bonding between hybrid fillers and matrix, agglomeration of kenaf bast fibers and irregularity of shapes and size of rice husks particulates. Water absorption results revealed that hybrid composites water uptake decreased as the rice husks particulates loading increased. This was mainly due to rice husks have rich content of silica which increased the moisture resistance. Kenaf bast fiber reinforced epoxy bio-composite has the highest water intake due to its hydrophilic characteristics.