Effects of acrylonitrile content on thermal characteristics and thermal aging properties of carbon black-filled NBR composite

Abstract

In seal applications, thermal characteristics and thermal aging properties of rubber are essential factors in determining the applicable temperature range and lifetime of the seal. In this study, thermal characteristics and thermal aging properties of the acrylonitrile butadiene rubber composite in response to the acrylonitrile (ACN) content were investigated. Thermal stability, glass transition temperature ( T g), and dynamic property were determined by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis, respectively. The results showed that T g, thermal decomposition temperature, and tan δ were increased as the ACN content increased. To investigate the thermal aging properties of the composite, the composite was subjected to an accelerated thermal-oxidative and thermal aging process at 100°C for 168 h. The aged composites were evaluated by investigating the change in cross-link density, mechanical properties, and elastic recovery. The change in the chemical functional group was also studied using attenuated total reflectance Fourier transform infrared spectroscopy. The results indicate that subjecting the composite to thermal-oxidative and thermal aging process decreased the elongation at break and elastic recovery, while the cross-link density, Shore A hardness, and 100% modulus were increased. All of the properties were also dependent on the ACN content as well as the aging conditions.