Standardization of Ozone Testing

Abstract

Abstract THE progressive deterioration of soft vulcanized rubber, proceeding independently of actual wear, has always been a source of annoyance to the trade. Although evidences of such deterioration are varied in character, the many forms may be conveniently classified as surface deterioration and deterioration throughout the rubber. Surface deterioration, characterized by superficial film formation, is greatly accelerated when vulcanized rubber is exposed to light, particularly rays of short wave length, but that this function of light in the destruction of rubber is indirect in operation was recognized as early as 1883. by Burhardt (Jour. Soc. Chem. hid. 2, 119, 1883). The agency responsible for the changes which rubber undergoes on exposure to the atmosphere is undoubtedly oxygen, and suggested by Spiller (Jour. Chem. Soc. [London] 18, 44, 1865), as far back as 1865. That oxygen is essential for the deterioration of rubber has been shown by Fickenday (Kolloid Ztg. 9, 81, 1911), and many others since. The effect of sunlight on either raw or vulcanized rubber, is believed by Henri (Caout. et Gutta Percha 7, 2848, 1909) to be analogous, although Peachy and Leon (Jour. Soc. Chem. Ind. 37, 56T, 1918) offer the opinion that vulcanized rubber oxidizes less rapidly than raw rubber. Later investigators have proceeded still further in their conclusions, and Tuttle (The Rubber Age, N. Y. 8, 271-2, 1921) states, after studying the acetone solubility curves of vulcanized rubber exposed to light, that the action of the latter is one of oxidation, which when once started proceeds rapidly, due to the catalyzing effect of small amounts of oxidized rubber so formed.