Dependence of abrasion behavior on cross-linked heterogeneity in unfilled nitrile rubber

Four unfilled nitrile rubber specimens with different sulfur contents were prepared, from 1.0 to 1.7 phr. The friction energy density, morphology of abraded surface, cross-linking density and fracture energy of NBR specimens were studied. Additionally, the dissipated energy by tapping mode atomic force microscopy was determined to investigate cross-linked heterogeneity of the network. It was found that the cross-linked heterogeneity plays a critical role in abrasion performance of NBR. Then a model of network was proposed. The simulation results indicate that the higher level of cross-linked heterogeneity would increase the probability of network failure and lead to inferior abrasion resistance, which are accordant with the results of experiments.