Study on Mechanical and Tribological Properties of Nitrile Butadiene Rubber and Hydrogenated Nitrile Butadiene Rubber Blends Reinforced With Spherical Nano‐ <scp> Al ₂ O ₃ </scp>

ABSTRACT Nitrile butadiene rubber (NBR) and hydrogenated nitrile butadiene rubber (HNBR) were blended at different weight ratios, with spherical nano‐alumina (nano‐Al 2 O 3 ) as the reinforcing filler. The vulcanization behavior, cross‐linking density, mechanical performance, wear resistance, and wear mechanisms of the NBR/HNBR composites filled with nano‐Al 2 O 3 were systematically characterized via vulcanization curve analysis, equilibrium swelling tests, tensile and compression tests, friction‐wear measurements, scanning electron microscopy (SEM) observations, and attenuated total reflection Fourier transform infrared spectroscopy (ATR‐FTIR). Results reveal that the torque difference and cross‐linking density of the composites exhibited nonlinear variations with increasing the ratio of NBR to HNBR. Notably, the composite with an NBR/HNBR weight ratio of 70:30 achieved superior mechanical properties and optimal wear resistance, accompanied by the lowest volume wear rate among all tested formulations. The key insight is that the NBR/HNBR ratio of 70:30 facilitated the formation of a synergistic interpenetrating cross‐link network. NBR contributed abundant cross‐link active unsaturated double bonds to densify the network, while the saturated main chain of HNBR imparted structural stability and inhibited crack propagation. This work provides a feasible strategy for optimizing rubber composites by regulating NBR/HNBR blending ratios, offering guidance for the design of high‐performance rubber materials for tribological applications.