Aging Properties of Nitrile Rubber in Medium under High-Low Cyclic Temperature Environment

Abstract

To obtain the aging mechanism of a certain kind of missile sealing nitrile rubber material under high and low-temperature cycle conditions, the nitrile rubber sealing ring was subjected to the accelerated aging test of high and low temperature circulating oil medium. The changes of compression set, mechanical properties, microstructure, molecular structure and dynamic mechanical properties under the condition of temperature-changing oil medium were studied. The dissociation energy of several important chemical bonds of nitrile rubber molecules was calculated. The test results show that the maximum tensile strength and elongation at break of special nitrile rubbers decrease with the increase of the number of cycles, and the compression set rate of nitrile rubber samples stored in oil medium increases gradually in the early stage of aging. Large, slightly restored in the late stage of aging, as the aging time increases, the side groups of the nitrile rubber molecules decompose and the main chain flexibility increases.