Radiation vulcanization and properties of hydrogenated butadiene-acrylonitrile rubber

Vulcanized hydrogenated butadiene-acrylonitrile rubber (HNBR) without the use of vulcanization reagents was cross-linked by γ-ray irradiation. The vulcanization behavior was investigated at the absorbed dose range of 0 ∼ 300 kGy. The micromorphology and dynamic mechanical properties were characterized and analyzed by dynamic mechanical analysis and scanning electron microscope, respectively. The results indicated that the HNBR sample was vulcanized by γ-ray irradiation without vulcanization reagents. With an increase in the absorbed dose, the elastic torque simultaneously increased when the mold filling deformation decreased due to the cross-linked reaction of HNBR. The HNBR sample exhibited excellent mechanical properties and oil resistance when the absorbed dose of 200 ∼ 250 kGy. Compared with the chemical-vulcanized HNBR, the retention rate of tensile strength and the elongation at break of radiation-vulcanized HNBR increased by 24% and 39%, respectively, in air at 150 ℃ for 70 h. Moreover, the compression set of the radiation-vulcanized HNBR (46.20%) was lower than that of chemical-vulcanized HNBR (58.56%) after being immersed in No. 903 oil at 150 ℃ for 24 h. The results prove that radiation vulcanization improves hot-air and hot-oil aging resistance and is, thus, expected to achieve both high performance and long service life. (authors)