PERFORMANCE OF URETHANE VULCANIZATES IN ENVIRONMENTS OF HIGH HUMIDITY
ROCK ISLAND ARSENAL IL
Pagination or Media Count:
Polyester urethane elastomeric end items have exhibited severe breakdown after service periods of as little as one to two years. The rubber becomes tar-like within an unreasonably brief period of service and is rendered unfit for further use. Duplication of this rubber failure under laboratory conditions was accomplished by exposing specimens over water at 158 F and at room temperature. Two modes of degradation appear to occur simultaneously and independently of one another i.e., hydrolysis or chain scission of specimens exposed at 158 F and microorganism attack of the specimen at room temperature accompanied by hydrolysis. A polycarbodiimide and pentachlorophenol demonstrate their ability to retard chain scission and microor.anism attack, respectively. Unfortunately, pentachlorophenol interferes somewhat with the efficiency of the polycarbodiimide when the two materials are used in admixture. Polyether urethane vulcanizates, containing no special additives, are not adversely affected by environmencs of high humidity.
- Elastomers and Rubber