Fluorinated heterocyclic polyamides

New thermostable fluorinated heterocyclic polyamides have been synthesized by low-temperature solution polycondensation of various aromatic diamines which contain phenylquinoxaline or 1,3,4-oxadiazole units, with a diacid chloride containing imide rings, hexafluoroisopropylidene (6F) group and methylene bridges. These polymers are readily soluble in polar amidic solvents, such as N-methylpyrrolidinone (NMP) and dimethylformamide (DMF) and can be cast into flexible thin films from solutions. They show high thermal stability with decomposition temperature being above 350°C and glass transition temperature in the range of 260–306°C, good electrical insulating properties with dielectric constant being in the range of 3.3–3.6 and tough mechanical properties.