Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE The effects of ratios of NBR to HNBR on the vulcanizing properties, mechanical properties and wear resistance of NBR/HNBR blends were investigated experimentally in this work. The results indicate that the NBR/HNBR composite with the ratio of 70:30 had better mechanical properties and anti-wear performance than those of the composites with blending ratios of 30:70 and 50:50.

ABSTRACT
Nitrile butadiene rubber (NBR) and hydrogenated nitrile butadiene rubber (HNBR) were blended at different weight ratios, with spherical nano-alumina (nano-Al2O3) 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-Al2O3 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.