The thermal aging tests of EPDM and NBR diaphragm materials for nuclear power were carried out at 100℃ and 150 ℃ for different time.And, the tensile properties, hardness, fatigue properties and micro-morphology of rubber diaphragm materials were tested and characterized by universal testing machine, Shaw hardness tester, tensile fatigue testing machine, scanning electron microscope and Fourier transform infrared spectroscopy. The results showed that the elongation at break and the strength at break of EPDM decreased with the increase of aging time, while the hardness increased slowly. The elongation at break of NBR decreaserd slowly, the strength at break and the hardness increasesd slowly at 100℃. The elongation at break and the strength at break decreased sharply and the hardness increasesd linearly at 150℃.Under the same aging time, the higher the aging temperature, the smaller the elongation at break and the strength at break, and the greater the hardness. The fatigue resistance of EPDM and NBR materials decreased to a certain extent with the increase of aging time and temperature, and the fatigue resistance of NBR materials decreased greatly. The results of infrared spectroscopy analysis showed that the absorption peaks of hydroxyl and carbonyl groups of EPDM materials increased with aging time, while the absorption peaks of NBR materials decreasd with aging time. SEM micromorphology analysis showed that the surface of EPDM and NBR samples was smooth before aging, and with aging time increasing, more accumulation substances appeared on the surface of samples. The higher the aging temperature, the rougher the surface of the sample.
Synthetic Materials Aging and Application