Apparent Crosslinking Research Articles

Benzothiazyl Disulfide-Accelerated Vulcanization of Carbon Black Loaded Natural Rubber

Abstract Sulfur group analyses of reinforced MBTS accelerated vulcanizates reveal chemical differences which can be related to the surface chemistry of the carbon blacks. The analytical procedure is based on the treatment of the vulcanizate with lithium aluminum hydride followed by potentiometric titration of sulfide and mercaptan sulfur. The polysulfide crosslink density and the values of x in the R—S—Sx—S—R polysulfides are dependent upon the quinone content of the carbon black. Both the quinone content and the surface area of a carbon black appear to determine its influence on the disappearance of free sulfur and the apparent crosslinking of the vulcanizate.