Polyisophthalamides with Pendant 3,4,5,6-Tetrachlorophthalimide Groups

New polyamides containing pendant chlorinated phthalimide groups have been synthesized by solution polycondensation of various aromatic diamines with 5-(3,4,5,6-tetrachlorophthalimide)isophthaloyl chloride. These polymers are soluble in such polar amidic solvents as N-methyl-2-pyrrolidinone and N,N-dimethylformamide and give transparent flexible films by casting from solutions. They show high thermal stability with a decomposition temperature above 400°C and no glass transition up to 350°C. They have low dielectric constants in the 3.6–4.0 range and good tensile properties.