Synthesis and characterization of novel polyimides with 2,2-bis[4(4-aminophenoxy)phenyl]phthalein-3′,5′-bis(trifluoromethyl)anilide

2,2-Bis[4(4-aminophenoxy)phenyl]phthalein-3',5'-bis(trifluoromethyl)anilide (6FADAP), containing fluorine and phthalimide moieties, was synthesized via the Williamson ether condensation reaction from 1-chloro-4-nitrobenzene and phenol-phthalein-3',5'-bis(trifluoromethyl)anilide, which was followed by hydrogenation. Monomers such as 2,2-bis[4(4-aminophenoxy)phenyl]phthalein-anilide containing phthalimide groups and 2,2-bis[4(4-aminophenoxy)phenyl]phthalein containing only phthalein moieties were also synthesized for comparison. The monomers were first characterized by Fourier transform infrared (FTIR), H-1 NMR, F-19 NMR, elemental analysis, and titration and were then used to prepare polyimides with 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride. The polyimides were designed to have molecular weights of 20,000 g/mol via off-stoichiometry and were characterized by FTIR, NMR, gel permeation chromatography (GPC), differential scanning calorimetry, and thermogravimetric analysis. Their solubility, water absorption, dielectric constant, and refractive index were also evaluated. The polyimides prepared with 6FADAP, containing fluorine and phthalimide moieties, had excellent solubility in N-methylpyrrolidinone, N,N-dimethylacetamide, tetrahydrofuran, CHCl3, tetrachloroethane, and acetone, and GPC analysis showed a molecular weight of 18,700 g/mol. The polyimides also exhibited a high glass-transition temperature (290 degreesC), good thermal stability (similar to500 degreesC in air), low water absorption (1.9 wt %), a low dielectric constant (2.81), a low refractive index, and low birefringence (0.0041). (C) 2003 Wiley Periodicals, Inc.