A new diamine monomer containing flexible sulfone, sulfide, and amide units was prepared via three steps. Nucleophilic chloro displacement reaction of 4-aminothiophenol with 4-nitrobenzoyl chloride in the presence of propylene oxide afforded N-(4-mercapto-phenyl)-4-nitrobenzamide and subsequent reduction of the nitro intermediate led to 4-amino-N-(4-mercapto-phenyl)benzamide. Two moles of this amino thiophenol compound was reacted with bis-(4-chloro phenyl)sulfone to provide a novel diamine monomer. The diamine was reacted with aromatic dianhydrides to form polyimides via a two-step polycondensation method, formation of poly(amic acid)s, followed by chemical imidization. The resulting polymers were characterized and their physical properties including thermal behavior, thermal stability, solubility and inherent viscosity were studied.
