New poly(amide‐imide)s syntheses, 6. Preparation and properties of poly(amide‐imide)s derived from 2,7‐bis(4‐aminophenoxy)naphthalene, trimellitic anhydride and various aromatic diamines

Abstract

AbstractAn imide ring‐containing dicarboxylic acid, 2,7‐bis[4‐(N‐trimellitoyl)phenoxy]naphthalene (1,1′,3,3′‐tetraoxo‐2,2′‐[2,7‐naphthylenedioxybis(1,4‐phenylene)]di‐1H, 3H‐isoindole‐5‐carboxylic acid (3)), was prepared by condensation of 2,7‐bis(4‐aminophenoxy)naphthalene (4,4′‐(2,7‐naphthylenedioxy)dianiline) and trimellitic anhydride (1,2,4‐benzenetricarboxylic acid 1,2‐anhydride). A series of new aromatic poly(amide‐imide)s 5 containing bis(phenoxy)naphthalene moieties having inherent viscosities of 0,8–1,57 dL/g were prepared by direct polycondensation of this diimide‐diacid 3 with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents in 1‐methyl‐2‐pyrrolidone (NMP) in the presence of calcium dichloride. Polymers 5 show excellent solubility in polar solvents such as NMP, and most of them could be cast into transparent and tough films. Measurements of wide‐angle X‐ray diffraction revealed that those polymer containing p‐phenylene or oxyphenylene groups are partially crystalline. Amorphous members exhibit glass transition temperature in the range of 250–311°C. Thermal analyses indicated that these polymers are fairly stable, and the 10% weight loss temperature were recorded in the ranges of 526–575°C in nitrogen and 481–556°C in air.