1.The polarity of NBR and acrylonitrile content

The acrylonitrile content of NBR is from 15% to 53%. With the increase of ACN, the molecular polarity increases, the interaction between molecules increases, and the cohesive energy density increases. The performance of NBR changes as follows: molecular chain flexibility, elasticity, and resistance. Low temperature, adhesion, insulation, and density, modulus, hardness, air tightness, strength, wear resistance, heat generation, compression set, antistatic properties, resistance to non-polar oil Increase

2.Unsaturation and acrylonitrile content of NBR

The relative molecular masses of acrylonitrile and butadiene are 54 and 53, respectively, so the mass ratio of the two is approximately equal to the ratio of the amount of the substance. When the ACN content is 15%, the ratio of the amount of the acrylonitrile/butadiene substance on the macromolecular chain is about 1/5.7. When the ACN content is 53%, the upper ratio is about 1/1, and the degree of unsaturation decreases. _ So with the increase of ACN, NBR’s aging resistance to heat, oxygen, ozone, weather, etc. will be improved. The general aging resistance of NBR is slightly better than that of SBR.