Oxidative polymerization of diphenylamine: Synthesis and structure of polymers

Three procedures for the chemical oxidative polymerization of diphenylamine, namely, in solutions of sulfuric acid, in an H₂SO₄-tert-butanol mixture, and via the interfacial process, are considered. It was shown that the highest molecular mass products are formed by the interfacial process. Oxidative hydrolysis and chain termination reactions predominate in a homogeneous medium. The effects of polymerization conditions, such as the concentration of reagents, their ratio, and the reaction temperature, on the yield and molecular-mass characteristics of polydiphenylamine were studied. The structure of reaction products was investigated by UV spectroscopy. It was demonstrated that, even when ammonium persulfate is in excess, the degree of oxidation of polydiphenylamine is rather small and chain propagation proceeds as a C-C rather than N-C addition as in the case of aniline.