Soluble fluoro-polyimides derived from 1,3-bis(4-amino-2-trifluoromethyl- phenoxy) benzene and dianhydrides

Soluble fluoro-polyimides have been synthesized by reacting of a fluorine-containing aromatic diamine, 1,3-bis(4-amino-2-trifluoromethylphenoxy) benzene(diamine 3), with aromatic dianhydrides to yield poly(amic acid)s which were then cyclized to yield polyimide by either thermal or chemical imidization method. The new tri-aromatic ring diamine, with trifluoromethyl groups at β position of amine group and bridged by ether bonds, was obtained by reduction of the corresponding dinitro-compound which was synthesized by coupling of 2-chloro-5-nitro-1-trifluoromethylbenzene with 1,3-hydroquinone in presence of strong base. Homogeneous and stable polyimide solutions with >12–15 wt.% of solid content were obtained. High quality and purity polyimide films have been prepared which exhibited excellent thermal stability, low moisture absorption and high hygrothermal stability.