Mechano-chemical reactions of polymers. formation of free radicals in stressed rubber

✍ Scribed by William D. Potter; Gerald Scott

• Publisher: Elsevier Science
• Year: 1971
• Tongue: English
• Weight: 431 KB
• Volume: 7
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(71)90081-4

✦ Synopsis

It has been found that free radicals produced in cross-linked rubbers subjected to high stresses can be detected in E.S.R. either as alkylperoxy radicals or by reacting with a phenol which can give rise to a stable free radical (galvinoxyl). This reaction occurs only during the first 1½ hr of stressing and corresponds to a period of stress relaxation in the rubber. The stable aryloxy radical disappears slowly in the absence of stress by a first order reaction the rate constant of which increases with the application of stress. This is interpreted in terms of a stress activated reaction of galvinoxyl with the rubber network, superimposed on the chain scission reaction and believed to be related to the observed activation of rubber to oxygen by stress.