Rolling and sliding wear properties of hybrid systems composed of uncured/cured HNBR and partly polymerized cyclic butylene terephthalate (CBT)

The phase structure, rolling and sliding wear properties of the hybrids composed of uncured/cured hydrogenated acrylonitrile/butadiene rubber (HNBR) and partly polymerized cyclic butylene terephthalate oligomers (CBT) were investigated. The ratio between HNBR and CBT was varied in the hybrids between 1:0.5 and 1:2. The CBT conversion and phase structure were studied by extraction, differential scanning calorimetry, and dynamic-mechanical thermal analysis.The rolling and sliding wear behaviors of the hybrids under unlubricated condition were determined by using various wear test rigs. It was found that the partly polymerized CBT worked as reinforcement in the HNBR matrix. The specific wear rate of the compounds usually decreased with increasing amount of CBT in both rolling and sliding wear tests. The coefficient of friction (COF) of the hybrids strongly depended on the type and configuration of the wear tests. Dynamic vulcanization of the HNBR in the HNBR/CBT mixes mostly improved the tribological performance. The wear mechanisms were studied as a function of CBT content and discussed.