Effect of swelling nitrile rubber in cyclohexane on its ageing, friction and wear characteristics

The swelling-induced ageing and tribological behaviors of nitrile rubber (NBR) samples with two different acrylonitrile contents, 18 wt% and 41 wt% (i.e., N18 and N41), in cyclohexane were investigated using static swelling and reciprocating wear experiments, respectively. The interaction between swelling-induced ageing and wear was also preliminarily researched in order to reveal the wear mechanism of NBR in cyclohexane at the different loads. The results showed that swelling-induced ageing of NBR occurred and its surface properties gradually weakened with increasing of swelling time. The wear volume of swelled NBR rubber in cyclohexane was higher than that of original one due to its lower shearing strength. At the lower load, the wear loss of NBR samples in cyclohexane was relatively low, and the wear process further accelerated the swelling-induced ageing of NBR samples. At the higher load, the wear loss of NBR samples in cyclohexane was dramatically high due to the change in wear mechanism from mild abrasive wear to severe abrasive wear, and the swelling-induced ageing of the NBR samples accelerated the wear process. N41 possessed better swelling-induced ageing and wear resistance to cyclohexane than N18, resulting from its higher crosslink density and proportion of crosslink chain.