SYNTHESIS AND CHARACTERIZATION OF NEW SOLUBLE AROMATIC POLYIMIDES FROM 3,4-BIS(4-AMINOPHENYL)-2,5-DIPHENYLPYRROLE AND AROMATIC TETRACARBOXYLIC DIANHYDRIDES

Novel aromatic polyimides containing tetraphenylpyrrole unit were synthesized from 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole and various aromatic tetracarboxylic dianhydrides by the usual two-step procedure that included ring-opening polyaddition and subsequent thermal cyclodehydration. These polymers had inherent viscosities in the 0.20-0.65 dL/g range and were practically amorphous as shown by the X-ray diffraction studies. All the polyimides except for polypyromellitimide were easily soluble in a wide range of organic solvents such as o-chlorophenol, pyridine, 1,3-dimethyl-2-imidazolidone, NN-dimethylacetamide, and N-methyl-2-pyrrolidone at room temperature. These polyimides had high glass transition temperatures of 302-359-degrees-C and exhibited 10% weight loss at temperatures above 510-degrees-C in nitrogen.