Influence of Binary Curing System on the Nitrile Rubber Mechanical Properties

The effect of different sulphur-based curing systems on the nitrile rubber mechanical properties was assessed. High acrylonitrile content nitrile rubber compositions were prepared with different amounts of N-cyclohexyl-2-benzothiazole-sulfenamide (CBS), tetramethylthiuram disulfide (TMTD) and sulphur. The following tests were conducted: crosslink density, hardness, and stress-strain tests. Scanning electron microscopy, infrared and NMR spectroscopies, and statistical analyses were carried out to bring new interesting aspects to this topic. Crosslink density was statistically influenced by the amount of TMTD and sulphur, whereas no significance was observed for CBS content. Tensile strength was above the optimum point regarding the crosslink density. Time-dependent exudation of TMTD was observed when added in higher concentration.