Effect Of Stress Relaxation On Accelerated Physical Aging Of Hydrogenated Nitrile Butadiene Rubber(HNBR)

Due to its significant hyper/visco-elasticity,good oil resistance,low abrasion rate and compressive set resistance,hydrogenated nitrile butadiene rubber(HNBR)has been widely used in the industrial applications such as seals,shockwave absorbers and ball-bearing gaskets.Since the stress relaxation is a common phenomenon for polymers,its effect on the stress/strain accelerated aging of the hydrogenated nitrile butadiene rubber(HNBR)cannot be ignored.Therefore,an accurate evaluation approach of physical aging with the consideration of stress relaxation will help to better understand the long-term performance and reliability of rubber components.In order to investigate the effect of relaxation on the accelerated aging tests of HNBR,following works were carried out in this paper:(1)Relaxation tests of HNBR under the same condition as aging test were performed.The classic time-temperature-strain superposition principle(TTSSP)was used to conduct relaxation modulus master curve.With the master curve and the general Maxwell model,the long-term relaxation behavior can be predicted;(2)To include the influence of stress relaxation on the accelerated aging process,a modified time-temperature-strain superposition principle considering stress relaxation(TTSSP-R)was proposed;(3)Based on the proposed time-temperature-strain superposition principle considering stress relaxation(TTSSP-R),the seal and damping properties of HNBR after aging were discussed and their long-term evolution were analyzed and summarized.