Influence of Carbon Black Content in Rubber Compound on the Properties of Nitrile Rubber

The article presents the results of a comprehensive study of the effect of medium-active carbon black N 550 on the properties of nitrile elastomer. It has been established that the optimal physical and mechanical characteristics are achieved with a content of 60–80 phr of carbon black: the maximum relative elongation is observed at 60 phr, while the best wear resistance and strength indicators are at 80 phr. Exceeding this concentration leads to deterioration of properties due to oversaturation of the system. The temperature and performance characteristics of the materials are studied. It is shown that thermal aging causes a decrease in elasticity and an increase in strength, and these effects weaken with an increase in the carbon black content. Water saturation for 30 days leads to an insignificant decrease in hardness without changing the strength characteristics. The glass transition temperature does not depend on the carbon black content, but the segmental mobility of the matrix shifts to higher temperatures with an increase in the filler concentration. Particular attention is paid to the surface morphology and tribological characteristics. It was found that with a content of 80 phr of carbon black, the structure of the material has the smoothest surface, and samples with 60–80 phr demonstrate a specific wear pattern. The practical significance of the work is confirmed by the successful implementation of the developed formulation for sealing rings of the FIP M9.02.01 flow meter at the enterprise Vodokanal of Yakutsk. Operation of the products for more than 2 years confirmed their reliability and efficiency, and the seals continue to work.