Abstract

In Part I, reactions by which it is possible to identify Neozone, aldol-α-naphthylamine, tetramethylthiuram disulfide, and diphenylguanidine, when present alone or in the form of simple mixtures with inorganic ingredients, were described. These reactions can serve for the determination of these ingredients in complex mixtures as well, provided that the mixtures are first separated in the pure state. Chromatographic separation on a strip of filter paper is especially suitable for this process. It should be remembered that it is always difficult to determine the various ingredients in finished rubber products when they have undergone chemical changes or decomposition under the influence of high temperatures. In many cases the decomposition products have not been examined, and this naturally has hindered qualitative analysis of the mixtures. For this reason a study of the behavior of various ingredients under actual conditions of vulcanization and from this the development of methods of qualitative analysis became necessary. The author has shown that diphenylguanidine decomposes with formation of aniline under these conditions; it is also well known that diazoaminobenzene forms aniline and aminoazobenzene forms diphenylamine. In certain cases a specific ingredient can be detected by means of its decomposition products. Thus the presence of diphenylguanidine in the original mixture can be established if aniline is detected in the rubber and there are no other ingredients in the mixture which give off aniline during decomposition. In this work methods of detecting Neozone in raw rubber, rubber mixtures, and finished rubber products and also methods of determining mercaptobenzothiazole, diphenylguanidine, diazoaminobenzene, and products of their decomposition are described.