Enhancement of friction behavior and self-healing capabilities in nitrile rubber through ZnO nanoparticles incorporation

This study investigates a novel approach to enhance XNBR composites through the incorporation of synthesized ZnO nanoparticles with controlled morphology. The ZnO nanoparticles, synthesized via a modified co-precipitation method, exhibited uniform size distribution with 90% of particles ranging between 35-55 nm. Dynamic mechanical analysis revealed dual transition behavior, with a distinct ionic transition peak emerging above the glass transition temperature. The storage modulus at room temperature increased from 3.2 MPa to 7.8 MPa with 7.5 phr ZnO loading, while maintaining elongation at break above 600%. Tribological testing demonstrated significant improvements, with the composite achieving a 78% reduction in wear rate and maintaining stable friction coefficients under dry sliding conditions. Temperature-dependent self-healing studies showed progressive improvement in recovery rates, with maximum efficiency achieved at 80°C. The formation of ionic clusters, confirmed through FTIR analysis, played a crucial role in both mechanical reinforcement and self-healing mechanisms. The optimized composite demonstrated a 30% increase in crosslink density compared to conventional ZnO-cured systems, leading to enhanced thermal stability with char yield improving from 8% to 15% at 600°C.