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-trifluoro-methylphenoxy) 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 P 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. (C) 2001 Elsevier Science Ltd. All rights reserved.