2-Bisbenzothiazole-2,2＇-disulfide (MBTS)-accelerated sulfur vulcanization, in the absence of ZnO, was studied using 2,3-dimethyl-2-butene (TME) as a model for polyisoprene. Reactions were carried out in sealed tubes at 150 degrees C and the residual curatives, intermediates, and products were analyzed by HPLC at various stages of the reaction. The formation of accelerator-terminated polysulfidic pendent groups is accompanied by the liberation of 2-mercaptobenzothiazole (MBT) and more MBT is liberated on crosslinking. Bis(alkenyl)-crosslinked products with varying degrees of sulfuration result. It was shown that crosslinking by a reaction between pendent groups and the model compound, and by disproportionation of pendent groups, leads to limited crosslinking. H2S was not evolved during crosslinking. 2,3-Dimethyl-2-butene-benzothiazole disulfide (TME-S(2)Bt) and 2,3-dimethyl-2-butene-1-thiol (TME-SH) were synthesized and it was shown that rapid crosslinking occurs between TME-S(x)Bt and TME-SxH (where x > 1), the reaction liberating MBT. (C) 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1395-1404, 2000.