Abstract
To study the relation between the fatigue of rubber and the solubility of antioxidants in rubber, PANA (Phenyl-α-naphthyl amine), which is a soluble antioxidant in rubber, DNPPD (Sym. Di-β-naphthyl-p-phenylen diamine), which is an insoluble one, oil (softener), and the control of NR, which has no additive, were used in the test. These materials were examined by repeated tension tests in air and in inert gas. As a result of these tests, the order of the term of life in air is found :
PANA > DNPPD > oil > control while in inert gas, it is oil > PANA > control > DNPPD
That is to say, in presence of oxygen, the soluble antioxidant in rubber lasted long under the fatigue. In inert gas, the soluble one lasted long too regardless of antioxidant. Consequently, it is supposed that the resistance to fatigue is due to the relaxation of the concentrated stress by those compounding agents.
