Enhancing the Reversion Resistance, Crosslinking Density and Thermo-Mechanical Properties of Accelerated Sulfur Cured Chlorobutyl Rubber Using 4,4′-Bis (Maleimido) Diphenyl Methane

Abstract

Vulcanizates of chlorobutyl rubber (CIIR) with the accelerated sulfur generally exhibit poor crosslinking density owing to the low level of unsaturation in the backbone of CIIR. Therefore, the sulfur cured CIIR shows inferior thermo-mechanical properties at elevated temperature. In addition to this, the vulcanization of CIIR with accelerated sulfur is limited at higher temperature due to reversion. To solve these problems, 4,4′-bis (maleimido) diphenyl methane (BMDM) was applied as a crosslinking additive along with the accelerated sulfur. The detailed curing studies have proved that the presence of BMDM greatly enhanced the rheometric torque and the reversion resistance while curing CIIR with accelerated sulfur even at higher vulcanization temperature. Moreover, the crosslinking densities of the sulfur cured CIIR have increased by 109% with the use of 1 phr BMDM and further rose to 380% with 5 phr BMDM. The improved crosslink density could enable reduction of the compression set of the sulfur cured CIIR to around 40% at 100 °C when it was vulcanized in the presence of 5 phr BMDM. The kinetic studies revealed that incorporation of this additive does not adversely affect the original vulcanization behavior of CIIR with accelerated sulfur, instead it marginally improved the speed of the vulcanization.

Biodegradable Gloves for Waste Management Post-COVID-19 Outbreak: A Shelf-Life Prediction

“…28 During the earlier stages of thermal aging, there is cross-links rearrangement from a polysulfidic to a monosulfidic chain. 29 Fluctuations at some points are probably caused by the balancing between the cross-link scission and the cross-link formation in the polymer. Both cross-link scission and crosslink formation occur simultaneously, and these reactions occur all the time in the aging process.…”

“…During the earlier stages of thermal aging, there is cross-links rearrangement from a polysulfidic to a monosulfidic chain . Fluctuations at some points are probably caused by the balancing between the cross-link scission and the cross-link formation in the polymer.…”

Effect of main chain modification during reversion on strain‐induced crystallization of polyisoprene rubbers

“…Reduction of crosslink density during reversion is considered as the main reason for performance degradation, so that some measures, like curing at relatively low temperature [2] or adding anti-reversion agents, [3][4][5][6][7] are taken in order to minimize the decrease in crosslink density. A lot of research [1,[8][9][10] has been done to study the effects of crosslink density on SIC to help further understand the mechanism of performance degradation due to reversion.…”

Application of Silica Supported Calix[4]arene Derivative as Anti-reversion Agent in Tire Tread Formulation

“…They examined rheometric curves and reported that BMDM significantly enhanced the reversion resistance. 11 In 2016, they applied BMDM in NR vulcanized with sulphur and described that the presence of 5 phr of BMDM significantly improves reversion resistance without adversely affecting the scorch time and cure rate. It also enhancement crosslink density and drops compression set value.…”