NBR has excellent oil resistance. Dinidium monomer can copolymerize into three different chain structures: cis, trans, and 1,2-alkyl. In a typical NBR structure, trans accounts for about 78%. Due to the presence of cyanide groups in the molecular chain structure of NBR, its oil resistance (such as resistance to mineral oil, liquid fuels, animal and vegetable oils, and solvents) is superior to that of natural rubber, chloroprene rubber, and styrene butadiene rubber. Compared with other rubbers, NBR has a wider range of operating temperatures, with a long-term operating temperature of 120oC. At the same time, NBR has good low temperature resistance, with a minimum glass transition temperature of -55oC.
NBR has good chemical stability and processing performance. As the content of acrylonitrile in its structure increases, its relative density increases, the vulcanization rate accelerates, and the tensile strength performance improves. However, the rebound performance decreases and the cold resistance deteriorates. Due to the easy electric field polarization of the cyanide group in NBR, its dielectric properties decrease, making it a semiconductor rubber. NBR can be classified into five categories based on the content of ACN: ultra-high, high, medium high, and medium low acrylonitrile. There are two production methods: continuous and intermittent polymerization. Continuous polymerization method is usually used for low variety and high yield production, with low consumption. Intermittent polymerization method is suitable for multi variety and small batch production, with a small number of polymerization tags used and high engineering construction consumption. So far, there is no apparent trend of mutual substitution.
Although nitrile rubber has excellent physical, mechanical, and processing properties, its long-term performance in acidic gasoline and high temperature (150oC) environments is not as good as fluorine like rubber and acrylic rubber. Therefore, German, Canadian, and Japanese companies have developed high-performance hydrogenated nitrile rubber (HNBR). In addition, we have also developed nitrile rubber with extremely cold resistance and high purity, as well as shuttle based nitrile rubber (XNBR).