Synthesis of diazoresin and its photocrosslinking reaction

Abstract

Diazoresins with different specific viscosities were prepared from diphenylamine-4-diazonium salt and paraformaldehyde in concentrated sulphuric acid with different ratios of CH2O/−N2+X-. In order to obtain a diazoresin with a specific viscosity in a given time at 0–5°C, more than a stoichiometric ratio was necessary. The photocrosslinking reaction of the diazoresins with various binder resins in solid film was investigated. The results show that the photocrosslinking reaction took place only in a system composed of diazoresin and binder resin containing −OH side-chain groups. The photodecomposition of diphenylamine-4-diazonium salt and its diazoresin in alcohol was studied. It was demonstrated that the diphenylamine aryl cation formed on decomposition is the dominant intermediate. The photocrosslinking mechanism between diazoresin and binder resin is discussed in a preliminary way. © 1998 SCI.