Weakening Mullins effect of coordination crosslinked nitrile rubber/copper sulfate/tetramethylthiuram disulfide vulcanizates

Abstract

The nitrile rubber （NBR） vulcanizates were prepared by coordination crosslinking of copper sulfate（CuSO4）/tetramethylthiuram disulfide（TMTD）. The vulcanization characteristics, mechanical properties and weakening Mullins effect under compression mode of the vulcanizates with different TMTD amounts were investigated the. The results showed that the [Cu（SnCNMe2）]·2+ complex formed by the synergistic effect of Cu2+ and TMTD was crosslinked with cyano group to form a three-dimensional network structure；the crosslinking density of NBR vulcanizates increased with increasing TMTD amounts；the Mullins effect of NBR vulcanizates was significantly obvious during the uniaxial cyclic compression, but could be weakened with increasing TMTD amount. Moreover, the maximum compressive stress under the same strain decreased with increasing the number of cycle times, which showed the stress softening phenomenon， and the instantaneous residual compression deformation increased with increasing the number of cycle times. The decrease range of maximum compressive stress and the increase range of instantaneous compression residual deformation were increased with increasing strain, and the Mullins effect was more remarkable. However, the decrease range of maximum compressive stress and the increase range of instantaneous compression residual deformation were weakened with increasing TMTD amount, and the Mullins effect was significantly weakened.

Keywords

• coordination crosslinking
• nitrile rubber
• tetramethylthiuram disulfide
• mechanical property
• weakening mullins effect
• synergistic effect