ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Some details for the construction of a modulus balance and thermostat are discussed. A new dumbbell type is developed for aging tests. In four stocks containing different accelerators, the function of copper applied as stearate is investigated. In the case of Santocure, a comparatively high sensitivity is found, and the t1/2 (TB) value for aging at 70°C. represents a sensitive measure of the prooxygenic effect, whereas relaxation times at 121° showed a smaller but definite variation. With MBT boosted with DPG only a limited effect was observed. Conversely, for the thiurams, copper addition produced a marked antioxidant effect comparable with the retardation normally effected by 2PHR of ordinary antioxidants. 0.05% copper showed an antioxidant activity equivalent to the 2PHR antioxidant. Consistent results were obtained for aging, relaxation, and rate of oxidation. The factors of retardation as might be expected, however, are not quite comparable. The factor of retardation for copper alone is 4-8 units. The copper develops in the thiuram vulcanizates a strong brown color giving colored solutions upon extraction with acetone and iso-octane. As the spectrophotometric determination of the colored complex is difficult, owing to the presence of the strong absorbing ZDC, the nature of the colored complex has not yet been ascertained, but it must somehow be responsible for the inverted action of copper found here.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1953.120100501
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