Synthesis and properties of organosoluble polyimides based on novel perfluorinated monomer hexafluoro-2,4-toluenediamine

New highly fluorinated aromatic polyimides based on hexafluoro-2,4-toluenediamine and commercially available dianhydrides (6FDA and ODPA) were synthesized by one-pot high temperature polycondensation in benzoic acid melt. Owing to the CF3 group and fluorine atoms in the meta-linked phenylenediamine fragment, these polyimides combine good solubility in organic solvents including such a low boiling point solvent as chloroform with high glass transition temperatures (330–345 °C), thermal and thermooxidative stability (T5 is >500 °C). The highly fluorinated polyimide films (hydrogen content is ≤1%) exhibit good dielectric properties and low water absorption as well as excellent optical transparency in the UV–vis region (cut-off wavelength is 311 nm for 6FDA-based and 357 nm for ODPA-based polyimides), which is very important for optoelectronic materials.