ACCELERATED DETERIORATION OF ELASTOMERS
Quarterly progress rept., no. 4, 1 May-31 July 1963
STANFORD RESEARCH INST MENLO PARK CA
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The object of this research is to find ways to degrade elastomers rapidly at or near room temperature. We are therefore studying the effects of soluble metal salts, hydrazines, and thiols on the rates of oxidation and chain scission of polyisoprene and polybutadiene in chlorobenzene as solvent. A number of complex cobalt compounds have been compared in oxidations of polyisoprene. A combination of t-butyl hydroperoxide and a cobaltous compound has given an immediate high rate of oxidation of undergraded rubber. At high extents of oxidation, cobaltic compounds are pre cipitated. In the fast reaction between phenyl hydrazine, polyisoprene, and oxygen, two mole molecules of oxygen are consumed per molecule of phenylhydrazine. A combination of phynylhydrazine and cobaltous acetylacet-te gives an effect intermediate between the fast but limited action of the hydrazine and the slower but long-sus tained action of the metal. Experiments on the p-thiocresol-initiated oxidation of polyisoprene show that low concentrations of this reagent produce the quickest degradation, but that higher concentrations produce larger effects after con siderable delay.
- Elastomers and Rubber