polyimides containing s‐triazine rings in the main chain: Synthesis and characterization

Abstract

Eight s‐triazine‐containing polyimides were synthesized by solution polycondensation of diisocyanates having an s‐triazine ring with pyromellitic dianhydride in dimethylacetamide. Polyimides derived from meta‐oriented diisocyanates were amorphous and soluble in dipolar aprotic solvents while those based on para‐oriented diisocyanates were semicrystalline and insoluble in organic solvents. However, all the polyimides were soluble in concentrated sulphuric acid. The polyimides showed similar patterns of decomposition with no weight loss below 300°C in air.