Synthesis of new soluble aromatic poly(amide imide)s from unsymmetrical extended diamine containing phthalazinone moiety

Abstract

Abstract The preparation of a new unsymmetrical kink non‐coplanar heterocyclic diamine, 1,2‐dihydro‐2‐(4‐aminophenyl)‐4‐[4‐(3‐phenyl‐4‐aminophenoxy)phenyl]‐(2 H )phthalazin‐1‐one (3), from a readily available unsymmetrical phthalazinone bisphenol‐like (1) was described. The diamine can be directly polymerized with various aromatic bis(trimellitimide)s (4a–e) by using triphenyl phosphite and pyridine as condensing agents to give a series of new aromatic poly(amide imides) (5a–e) containing the kink non‐coplanar phthalazinone heterocyclic units with inherent viscosities of 0.57–1.06 dL/g. The polymers were readily soluble in a variety of solvents such as N,N ‐dimethylformamide, N , N ‐dimethylacetamide, dimethylsulfoxide, N ‐methyl‐2‐pyrrolidinone, and even in pyridine and m ‐cresol and could be cast to form flexible and tough films. The glass transition temperatures were in the range of 315–340°C, and the temperatures for 5% weight loss in nitrogen were in the range of 487–512°C. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1516–1520, 2004