Effect of Sulfur and Dicumyl Peroxide on Vulcanization of Natural Rubber with Tetramethylthiuram Disulfide and Zinc Oxide

Abstract

Abstract The salient features of both non-elemental sulfur vulcanization by TMTD and elemental sulfur vulcanization promoted by TMTD both in presence and absence of ZnO and stearic acid have been studied. TMTD increases the rate of DCP decomposition and lowers the crosslinking maxima due to DCP depending on its concentration. However, with higher amounts of TMTD the initial rate of crosslinking is increased with the increased amount of TMTD, while crosslinking maxima are still lowered due to reversion. ZnO or ZnO-stearic acid, however, seems to alter the entire course of the reaction. Both the crosslink formation and TMTD decomposition are much higher in presence of ZnO or ZnO-stearic acid, but stearic acid seems to have no effect. The reaction mechanisms for TMTD accelerated sulfuration in absence and presence of ZnO have also been studied.