The effect of peroxide crosslinking on the synergistic crosslink of double bond and nitrile group of nitrile rubber in H2S environment

摘要

In the H2S environment, the double bonds and nitrile groups of pure nitrile rubber (NBR) are synergistically crosslinked to produce sulfur crosslinks [1]. However, the corrosion of NBR vulcanizate in H2S is unknown. To investigate the effect of crosslinked structure on NBR corrosion, a corrosion test of NBR cured by peroxide crosslinking in H2S is carried out. Researches find out that the vulcanizates are more susceptible to H2S than the raw rubber. The increment of sulfur element in vulcanizate is much higher than that of raw rubber, and the reduction of double bond is more severe than raw rubber, which is attributed to the alpha-tertiary carbon structure produced by peroxide crosslinking. The alpha-tertiary carbon greatly activates the double bond and allyl hydrogen (alpha-H), thereby promoting the reaction of 1,4-polybutadiene (1,4-PB) structural unit with H2S, thus exacerbating the corrosion of NBR, causing a serious decline in its performance.