Nanofiller effect on the mechanical properties of natural fiber reinforced polyurea composites

This work proposes a novel fiber-matrix pair consisting of polyaspartic polyurea (PAPUr) and jute to enhance the sustainability of natural fiber–reinforced polymer composites. The feasibility of producing this fiber-matrix pair using vacuum assisted resin transfer molding (VARTM) method, without the need for additional chemical surface treatment and post-curing processes, is evaluated. Furthermore, the ability to improve the existing mechanical properties of the composite using different nanofillers is investigated. For this purpose, tensile, three-point bending, and unnotched Charpy impact tests were conducted on unfilled composites and composites filled with 0.5, 1, 1.5 wt.% nano titanium dioxide (TiO 2 ) and graphene nanoplatelets (GNPs). The surface hardness of the composites was also examined. TiO 2 nanofiller significantly improved the mechanical performance of the composite, resulting in a 31.28% increase in tensile strength at 1 wt.%, a 20.6% increase in flexural strength at 1.5 wt.%, a 34.2% increase in impact strength, and a 19.68% increase in surface hardness compared to unfilled composites. Conversely, GNPs addition produced modest improvements in tensile strength (17.54% at 0.5 wt.%) and flexural strength (15.54% at 1.5 wt.%), but reduced impact resistance and surface hardness due to agglomeration, poor wetting and void formation related effects.