The chemistry of sulfur curing. Part II. Kinetics of vulcanization of an EPDM elastomer accelerated by tetramethylthiuram monosulfide and disulfide
✍ Scribed by James R. Wolfe Jr.
- Publisher
- John Wiley and Sons
- Year
- 1968
- Tongue
- English
- Weight
- 446 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
The induction periods and maximum cure rates of an EPDM gum rubber were determined by using the Monsanto oscillating disk rheometer and correlated against the initial concentrations of curing ingredients. Sulfur curing systems accelerated by TMTM and TMTD were used. The maximum cure rates of the TMTM-accelerated and the TMTD-accelerated EPDM terpolymer compounds differed significantly only at low sulfur concentrations where the TMTM-accelerated compounds had slower maximum cure rates. Above approximately the 1% concentration level, TMTM and TMTD were found increasingly to retard the maximum cure rates of the EPDM terpolymer compounds as the initial concentrations of the thiuram accelerators were increased. The maximum cure rates of the TMTM-and TMTD-accelerated terpolymer compounds were found to be variable order in initial accelerator concentration, second-order in initial cure site concentration, approximately half-order in initial sulfur concentration above 0.3% sulfur, and of a positive variable order in initial zinc oxide concentration.