Effect of nitrosamine safe diisopropyl xanthogen polysulfide accelerator on cure and static mechanical properties of natural rubber compounds

Sulfur vulcanization of natural rubber (NR) is mainly carried out with the use of accelerators in order to achieve desired network structure and consequently the specific material properties. Many traditional organic accelerators are made from secondary amines and are capable of nitrosation during and after vulcanization in the presence of nitrosating agents. Therefore, the use of most of the nitrosamine generating traditional accelerators in rubber formulations are restricted by stringent rules and regulations imposed by world environmental and health-related government agencies. Diisopropyl Xanthogen Polysulfide (DIXP) has been identified as a nitrosamine safe novel accelerator and literature on use of this accelerator in natural rubber compounds is limited. The aim of this study was to evaluate the influence of DIXP on cure and static mechanical properties of NR compounds. A series of NR compounds was prepared with DIXP by varying the accelerator dosage from 0.2 phr to 2.2 phr at 0.4 phr intervals. Cure and static mechanical properties of the compounds were evaluated and compared with those of the compounds prepared with the commonly used nitrosamine safe N-tert-butyl-2-benzothiazole sulfenamide (TBBS) accelerator. Results showed that most of the properties of NR compounds prepared with DIXP are inferior in comparison to those of the compounds prepared with TBBS. Nevertheless, NR compounds prepared with DIXP possessed satisfactory results in regard to optimum cure time and elongation at break.