DIRECT ATTACK OF OXYGEN ON AMINE ANTIOXIDANTS

A STUDY ON DETERIORATION AND STABILITY OF BR AND IR VI

Abstract

Reaetions between amine base antioxidants and oxygen have been Investigated with the following results :
(1) The antioxidants were thermally decomposed in the atmosphere and in an inert gas. Comparison of thermograms obtained thereby shows that in the atmosphere the antioxidants are for the greater part decomposed with oxidation, but in the inert gas the majority of them vaporized except some which were decomposed.
(2) Relatively low-temperature behaviors of antioxidants were investigated with respect to the mplecular weight, infrared-, ultraviolet absorption spectra and refractivity. It is surmised that certain changes occurred in ANA, PBNA, DPPD, etc., but no formation of a dimer was recognized.
(3) The antioxidants thus oxidized were added to rubber and their effects on rubber were evaluated in terms of viscosity change due to oxidation in the rubber solutions. Most of the antioxidants remained practically unchanged, except PBNA which exhibited a fast drop in viscosity. From the above results, it is known that most of the antioxidants exhibit no great change, except PBNA, which is likely to promote oxidation of rubber.