The attack of ozone on stretched rubber vulcanizates. III. Action of antiozonants

Publisher Website
Google Scholar
Abstract
The character and extent of protection by certain additives (antiozonants) have been investigated for a number of vulcanized rubbers over a wide range of ozone concentrations. Two distinct modes of action are found: a reduction in the rate of crack growth and an increase in the critical energy necessary for attack to occur. Neither seems explicable on a simple hypothesis of scavenging. Several materials which act in the first manner have been examined. They were found to be similar in effect, reducing the growth rate to about one fifth of its original value when a sufficient amount of the additive was present. The mechanism is obscure. Certain additives, notably N,N′‐dioctyl‐p‐phenylenediamine, also cause a striking and important increase in the critical energy condition. The circumstances under which this occurs have been studied, and a tentative hypothesis for the mode of action is advanced.