The effect of benzoic and stearic acids on 2-bisbenzothiazole-2,2Ј-disulfide (MBTS)-and tetramethylthiuram disulfide (TMTD)-accelerated sulfur vulcanization of polyisoprene compounds, containing ZnO, was studied at 150°C. In the presence of ZnO, the acids are rapidly converted to their zinc salts th
Effect of carboxylic acids on 2-bisbenzothiazole-2,2′-disulfide- and tetramethylthiuram disulfide-accelerated sulfur vulcanization. II. Vulcanization of polyisoprene in the absence of ZnO
✍ Scribed by W. J. McGill; S. R. Shelver
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 180 KB
- Volume
- 72
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
Polyisoprene was vulcanized by 2-bisbenzothiazole-2,2Ј-disulfide (MBTS)/ sulfur and tetramethylthiuram disulfide (TMTD)/sulfur in the absence and presence of benzoic and stearic acids. It was found that the crosslink density of MBTS vulcanizates is halved by the addition of carboxylic acids and this can be explained in terms of the attack of the acids on the accelerator polysulfides. TMTD polysulfides are more reactive toward polyisoprene than are MBTS polysulfides, and their addition to the polymer chain occurs before significant attack by the carboxylic acids can reduce the polysulfide concentration. Consequently, the acids have little effect on the crosslink density of TMTD vulcanizates.
📜 SIMILAR VOLUMES
Benzoic and stearic acids are shown to react with 2-bisbenzothiazole-2,2Јdisulfide (MBTS) and its polysulfides (MBTP) at vulcanization temperatures to form acid-accelerator complexes 2-benzoylthiobenzothiazole (BzM) and stearicthiobenzothiazole (StM), respectively. At higher temperatures MBTS, MBTP,
Stearic and benzoic acids were heated with 2-bisbenzothiazole-2,2Ј-disulfide (MBTS)/sulfur/ZnO and tetramethylthiuram disulfide (TMTD)/sulfur/ZnO isothermally at 150°C and in a DSC at 2.5°C/min, in the absence of rubber. The acids readily reacted with ZnO, and at vulcanization temperatures, little o
Polyisoprene was vulcanized with binary accelerator systems comprising mixtures of the zinc salts of tetramethylthiuram disulfide (TMTD) and 2-mercaptobenzothiale (MBT). Samples were heated in a DSC at a programmed rate, the reaction was stopped at points along the thermal curve, and the system was
The effect of ZnO and bis(2-mercaptobenzothiazole)zinc(II) [Zn(mbt) 2 ] on 2-bisbenzothiazole-2,2Ј-polysulfide (MBTP) formation in 2-bisbenzothiazole-2,2Ј-disulfide (MBTS) and MBTS/sulfur, in the absence of rubber, was studied by heating mixes isothermally for various times and analyzing products by