Hydrogenation of nitrile–butadiene rubber latex to form thermoplastic elastomer with excellent thermooxidation resistance

Abstract

AbstractHydrogenation of nitrile–butadiene rubber latex was carried out using hydrazine and hydrogen peroxide, with copper sulfate as catalyst and without pressurized hydrogen and organic solvent. A special inhibitor was used during hydrogenation to reduce gel formation. Various hydrogenation conditions were studied. The gel content of the hydrogenation product can be reduced to ∼15%, and hydrogenation degree can reach ∼87%. The hydrogenated product was characterized by infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. The hydrogenated product behaved as an oil‐resistant thermoplastic elastomer with excellent thermooxidation resistance, due to the absence of most double bonds and the presence of crystalline domains of polyethylene segments formed by hydrogenation of polybutadiene segments and nitrile groups. The higher the hydrogenation degree, the higher were the mechanical properties and thermooxidation resistance of the product. The product with a hydrogenation degree of 87% withstood thermooxidation quite well at 150°C for 65 h, maintaining ∼98% of its tensile strength and 96% of its ultimate elongation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1026–1031, 2003