Scratch behavior of the aged hydrogenated nitrile butadiene rubber

The objective of this work was to study the scratch behavior of the aged hydrogenated nitrile butadiene rubber (HNBR) including its scratch damage modes and their corresponding mechanism. A home-made device was used to perform the scratch testing on the virgin and thermal-aged HNBR substrates with a progressively increasing depth. The scratch resistance of HNBR declined dramatically with the increase of the aging time. The surface topography and damage modes of the scratched HNBR samples were investigated. Two types of scratch damage mode, i.e. the flake peeling and the helical-form damage were observed and both exhibited the characteristics of tearing. Specimens of two different geometries were used to measure the effects of aging time on tear strength of HNBR. It was found that there was a strong correlation between the strength data from two types of tear tests with the scratch damage modes. This finding provides a valuable guidance for improving the scratch resistance of the rubber materials and prolonging their service life.