New organo-soluble aromatic polyimides based on 3,3′,5,5′-tetrabromo-2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride and aromatic diamines

New aromatic tetracarboxylic dianhydride, having isopropylidene and bromo-substituted arylene ether structure 3,3',5,5'-tetrabromo-2,2-bis[4-(3,4-dicarboxy-phenoxy)phenyl]propane dianhydride, was synthesized by the reaction of 4-nitro-phthalonitrile with 3,3',5,5'-tetrabromobisphenol A, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). The novel aromatic polyetherimides having inherent viscosities up to 1.04 dL g(-1) were obtained by either a one-step or a conventional two-step polymerization process starting from the bis(ether anhydride) and various aromatic diamines. All the polyimides showed typical amorphous diffraction patterns. Most of the polyimides were readily soluble in common organic solvents such as N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), pyridine, and even in less polar solvents Like chloroform and tetrahydrofuran (THF). These aromatic polyimides had glass transition temperatures in the range of 256-303 degrees C, depending on the nature of the diamine moiety. Thermogravimetric analysis (TGA) showed that all polymers were stable, with 10% weight loss recorded above 470 degrees C in nitrogen. (C) 1999 John Wiley & Sons, Inc.