Preparation and properties of aromatic polyamides and polyimides derived from 3,3‐bis [4‐(4‐aminophenoxy) phenyl] phthalide

Abstract

Abstract3,3‐Bis[4‐(4‐aminophenoxy)phenyl]phthalide (II) was used as a monomer with various aromatic dicarboxylic acids and dianhydrides to synthesize polyamides and polyimides, respectively. The diamine II was derived by a nucleophilic substitution of phenolphthalein with p‐chloronitrobenzene in the presence of K2CO3. Polyamides IVa‐g having inherent viscosities of 0.77–2.46 dL/g were prepared by the direct polycondensation of diamine II with diacids IIIa‐g using triphenyl phosphite and pyridine as condensing agents. The polyamides were readily soluble in a variety of solvents such as N, N‐dimethylformamide (DMF), N,N‐dimethylacetamide (DMAc), and N‐methyl‐2‐pyrrolidinone (NMP) and afforded transparent and flexible films from the polymer solutions. These polymers had glass transition temperatures (Tgs) in the 227–307°C range and 10% weight loss temperatures occurred up to 450°C. Polyimides VIa‐e based on diamine II and various aromatic dianhydrides Va‐e were synthesized by the two‐stage procedure that included ring‐opening, followed by thermal or chemical conversion to polyimides. Most of the polyimides obtained by chemical cyclodehydration procedure were found to soluble in DMF, NMP, o‐chlorophenol, and m‐cresol. The Tgs of these polyimides were in the 260–328°C range and showed almost no weight loss up to 500°C under air and nitrogen atmosphere. © 1994 John Wiley & Sons, Inc.