Two Modes of Action of Antioxidants in Rubber

Abstract

Abstract It is a commonly accepted belief that antioxidants protect oxidizable products from the harmful effects of oxygen by retarding the rate at which these oxidizable products combine with oxygen. Consequently, if the oxidizability of a rubber mixture containing no antioxidant and the oxidizability of the same mixture to which such an agent has been added are measured under the same conditions, the absorption of oxygen would be expected to be distinctly less rapid in the second case. This has, in fact, been proved to be true in general, not only for rubber, but also for other substances which are protected by antioxidants. In a systematic study of a series of antioxidants of differing chemical compositions, various observations were made which gave indications that these products react in two different ways. In these experiments a rubber mixture of chosen composition was prepared as a blank or control, and was compared with other mixtures of the same base composition to which various antioxidants selected for study had been added in the same proportion in all cases.