Premium
Sulfur vulcanization of polyisoprene accelerated by benzothiazole derivatives. III. The reaction of 2‐bisbenzothiazole‐2,2′‐disulfide with sulfur and ZnO in polyisoprene
Author(s) -
Gradwell M. H. S.,
Mcgill W. J.
Publication year - 1996
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19960815)61:7<1131::aid-app9>3.0.co;2-n
Subject(s) - vulcanization , benzothiazole , sulfur , natural rubber , polymer chemistry , sulfenamide , chemistry , reaction mechanism , zinc , dithiocarbamate , materials science , organic chemistry , catalysis
The sulfur vulcanization of polyisoprene accelerated by 2‐bisbenzothiazole‐2,2′‐disulfide (MBTS) was investigated. Rubber compounds were heated in a DSC and removed at various temperatures along the DSC thermal curve. The rubber vulcanizate was analyzed for crosslink density and for residual reactants and extractable reaction products. MBTS reacts readily with sulfur, and the polysulfidic accelerator complexes react with the rubber chain to form pendent groups. Crosslinking results from hydrogen abstraction, by the benzothiazole pendent group, from a neighboring chain. 2‐Mercaptobenzothiazole, a product of crosslinking, also acts as an accelerator in the later stages of the reaction. MBTS has been shown not to react with ZnO and the higher crosslink densities obtained when ZnO is present are attributed to ZnO aiding the abstraction of the benzothiazole pendent group to give zinc mercaptobenzothiazole. A mechanism for the MBTS acceleration of sulfur vulcanization is proposed. © 1996 John Wiley & Sons, Inc.