Effectiveness of Titanium Dioxide Nano Fillers on Sisal fiber for Enhanced Mechanical Properties and Occupant Protection in Hybrid Nanocomposites

Vehicle occupant protection remains a critical concern in the field of crashworthiness technology. When integrated into polymer nanocomposites, natural fibres like sisal offer a high strength-to-weight ratio that can contribute to effective energy absorption during collisions. However, these fibers present challenges, such as poor hydrophilicity and moisture retention. This study employs compression molding techniques to create hybrid composites of sisal fibers, epoxy, and titanium oxide nano fillers. We particularly investigate how fiber orientation and the concentration of nano fillers can optimize mechanical and thermal properties, thereby enhancing occupant protection features. Our findings demonstrate that the orientation of sisal fibers and the incorporation of titanium oxide nano fillers in the epoxy matrix significantly influence the composite's mechanical and thermal characteristics. Composites reinforced with continuous sisal fibers exhibited an 11%-18% increase in impact strength compared to those with randomized fibers. Additionally, a 3% improvement in hardness was recorded for the same comparison. In the context of nano fillers, 8 wt.% of titanium oxide added to woven sisal fibers resulted in a peak tensile strength of 81.25 MPa. When 6 wt.% was added to woven sisal fibers, the composite reached an impact strength of 31.58 J and showed enhanced hardness properties. These improvements in mechanical properties are particularly crucial for energy absorption and dispersion, key factors in occupant protection during vehicular crashes. Interestingly, the density of composites was notably lower with 2 wt% TiO₂ compared to those with 4 wt% TiO₂, a factor attributed to the high-density nature of the nanoparticles.