부산대학교 도서관

Because of the increased demand for Acrylonitrile-butadiene rubbers (NBR) for automobiles, especially for the lip seals of ball bearings, research on friction and wear resistance under thermal aging conditions is necessary. In rubber, thermo-oxidation reaction occurs in ambient oxygen under high-temperature conditions. The result is that several mechanical properties, such as tensile strength, hardness, and toughness, are altered. This study quantitively evaluated the effects of load and thermal aging times on the wear resistance of NBR with the pin-on-disk wear test in accordance with the ASTM G99 standard. The wear resistance and wear rates were compared to determine the mechanical properties of thermally aged NBR. The mechanical properties were measured with a tensile test machine and the shore-A hardness test. The aging times correlated with the wear rates and mechanical properties of the non-aged and aged specimens. The changes in the chemical structure were analyzed by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. The morphologies of the NBR worn track wear were examined by scanning electron microscopy and a 2D profiler. The wear resistance of the NBR materials was evaluated by the specific wear rate. The correlation between the changes in the mechanical properties and wear volume loss with the aging times was investigated. Experimental wear modeling was then developed on the basis of the combined mechanical properties under thermal degradation