SYNTHESIS AND CHARACTERIZATION OF A NOVEL 3F-BASED FLUORINATED MONOMER FOR FLUORINE-CONTAINING POLYIMIDES

A novel '3F' fluorinated diamine monomer based on trifluoroacetophenone was synthesized via a straightforward, high yielding two-step procedure. Trifluoroacetophenone was reacted with 4-nitrophenyl phenyl ether to yield the 3F-dinitro compound, which was subsequently reduced to afford the fluorinated diamine, 1,1-bis[4-(4-aminophenoxy)phenyl]-1-phenyl-2,2,2-trifluoroethane (3FEDAM). New amorphous and semicrystalline polyimides based on 3FEDAM were prepared and characterized by differential scanning calorimetry, thermogravimetric analysis and wide-angle X-ray scattering (WAXS). In particular, the 3FEDAM-pyromellitic anhydride-phthalic anhydride material exhibited a glass transition temperature of 308 degrees C and a melting temperature of 476 degrees C which are quite similar to the values reported for '6F'-based systems. The semicrystalline nature was confirmed by WAXS analysis, and is consistent with the excellent solvent resistance observed for these polyimides.