Nanomodification Strategies Toward Sustainable Materials: Reinforcement Mechanisms and Performance Balance of Straw Fiber/Polypropylene Composites

ABSTRACT This study systematically evaluated the performance regulation mechanisms of three inorganic nanoparticles (1–4 wt%)—titanium dioxide (TiO ₂ ), zinc oxide (ZnO), and silicon carbide (SiC)—in alkali‐treated straw fiber/polypropylene (PP) composites based on polypropylene. All three nanoparticles were melt‐blended with fibers and PP in industrial‐grade powder form to achieve uniform dispersion, followed by injection molding. The results showed that different nanoparticles exhibited different reinforcement mechanisms: TiO ₂ mainly regulated crystallization behavior and improved wear resistance through heterogeneous nucleation; ZnO significantly improved toughness through interfacial energy dissipation and grain refinement; and SiC improved load‐bearing capacity due to its high hardness. Performance tests showed that 4 wt% SiC increased tensile strength by 12.2%, while 3 wt% ZnO achieved an elongation at break of 7.25%, exhibiting the best toughness enhancement effect. Combined with microstructure and tribological analysis, this study revealed the structure–property relationship between nanoparticle type, dispersion state, and interfacial structure. Comprehensive performance test results show that 3 wt% TiO ₂ and 3 wt% ZnO can achieve the best balance between mechanical properties and wear resistance, while the amount of SiC added should be controlled between 1 and 3 wt% to avoid interface failure.