Mechanical and physical characterization of PLA composites reinforced with okra fiber and silica nanoparticles

Abstract This research develops sustainable, high-performance biocomposites by reinforcing polylactic acid (PLA) with natural okra fiber and silica nanoparticles. Composites were fabricated with varying weight percentages of okra fiber (20 wt%, 30 wt%, and 40 wt%) and further enhanced with silica nanoparticles. The complete set of mechanical and physical data across all compositions shows that neat PLA had the lowest performance (50 MPa in tensile strength, 110 MPa in flexural strength, 4.0 kJ/m 2 in impact performance, and a Shore D hardness of 70). Incorporating okra fiber increased these values up to 62 MPa, 135 MPa, 7.1 kJ/m 2 , and 76, respectively, at 30 wt% fiber loading but also raised void content and water absorption. Adding silica nanoparticles to the PLA/30 wt% okra fiber composite further enhanced performance, peaking at 2 wt% silica. The composite demonstrated improved mechanical behavior, attaining 68 MPa in tensile strength, 148 MPa in flexural strength, 8.4 kJ/m 2 in impact strength, and a hardness rating of 80 on the Shore D scale. The void content reduced to 1.9 %, and water absorption minimized to 21 % after 12 days. These results demonstrate a clear synergistic effect between natural fibers and silica nanoparticles, leading to improved interfacial adhesion, structural integrity, and moisture resistance. Compared to similar composites in the literature, the developed hybrid system exhibits superior mechanical behavior, confirming its potential for use in environmentally friendly and structurally demanding applications.