Study On Aging Behavior And Properties Of NBR/EVM And Performance Prediction

The properties of the blend were studied from the NBR/EVM blending ratio,curing system and protection system in this paper.The effects of different aging behaviors on the blend were investigated.Using the Arrhenius equation and WLF equation to predict the properties of blends.(1)The effects of blending ratio of NBR/EVM on the performance and performance prediction are studied.With the increasing of EVM content,the initial properties of the blends decreased and the aging resistance increased.The apparent crosslinking density of NBR rubber was 3.2 times faster than EVM rubber when aging at 100℃.The rate of increasing of the density of NBR is 2~2.5 times larger than EVM in the blend.The change of NBR phase determines the properties of the blend.The effect of aging time on the performance is greater than aging temperature.Using the Arrhenius equation to predict the compression set reaching 20%.It needs for 253 h at 25℃.(2)Under the DCP/TAIC vulcanization system,along with DCP/TAIC dosage increased by 0.2/0.1,EVM crosslink density increased by 30mol/m~3,NBR crosslink density increased by 65mol/m~3.The effect of aging time on the performance is greater than aging temperature.In the aging process,the crosslinking density of NBR increased by 3.5~4 times faster than EVM.The change of NBR phase determines the properties of the blend.Using the Arrhenius equation to predict the compression set reaching 35%,and it needs for 363 h at 25℃.WLF equation is used to predict creep reaching 2%.It needs for 153 s.Under the S/DCP vulcanization system,the effect of aging time on the performance is greater than the aging temperature.When the aging temperature of the blend increased by 15℃,the density of NBR increased by about 25mol/m~3,while the density of EVM was almost unchanged.The density of NBR increased by 7~8 times larger than that of EVM in the process of aging.Using the Arrhenius equation to predict the compression set reaching 35%,and it needs for 2009 h at 25℃.WLF equation is used to predict creep reaching 2%.It needs for 317 s.(3)The effect of the protective system on NBR/EVM blend and performance prediction was studied.Different MB/RD ratio had little effect on the initial properties of blends.The best aging resistance was MB/RD was equal to 1.2/0.8.Changing the amount of MB/RD mainly affected the crosslinking density of NBR phase after aging.The crosslinking density of NBR increased about 9 times of EVM in aging process.The crosslinking density of NBR/EVM is greater than 5/1 after aging.Tensile strength will rise.Using the Arrhenius equation to predict the compression set reaching 35%,and it needs for 1.2h at 110℃.WLF equation is used to predict creep reaching 2%.It needs for 397 s.