Thermal and Age-Resistance Properties of NR Gum Vulcanizates in EV Systems

Abstract

Abstract A comparative study of the cure behavior of thiocarbamyl sulfenamides both in the presence of MBTS and thiazole sulfenamides has been made at 140 and 170°C. It is observed that most of the NR vulcanizates obtained at 170°C are capable of retaining a considerable portion of torque, modulus, and tensile values obtained at 140°C. This provides information regarding the heat resistance of these vulcanizates. It is observed that ZDC's up to a certain concentration increases the thermal resistance of the NR vulcanizates, the maximum effect being produced by ZBD and ZPD. ZOD and ZPD above a critical concentration, impart a deleterious effect to NR gum vulcanizates where a drop in the R∞ value is observed. The age resistance property of the various combinations of thiocarbamyl sulfenamides plus MBTS and thiazole sulfenamides plus thiocarbamyl sulfenamides has been discussed. It is evident from the study that the former combination generally provides higher physical properties of the vulcanizates and better age-resistance than those obtained with the latter combination. Vulcanizates obtained with the CTOS-MBTS combination in the presence of ZDC's provide notable thermal as well as age-resistance.