Synthesis and characterization of new thermally stable aromatic copoly(ester–amide)s from diester‐dicarboxylic acids

Abstract

Two new aromatic diester-dicarboxylic acids containing furan rings, namely, benzofuro[2,3b]benzofuran-2,9-dicarboxyl-bis-pyridyl ester-4,4 -dicarboxylic acid and benzofuro[2,3-b]benzofuran-2,9-dicarboxyl-bis-phenyl ester-4,4 -dicarboxylic acid were synthesized by the reaction of benzofuro[2,3b]benzofuran-2,9-dicarbonyl chloride with 6-hydroxynicotinic acid and 4-hydroxybenzoic acid, respectively. These monomers were converted to aromatic copoly(ester-amide)s by reaction with various aromatic diamines via direct polycondensation. Polymers were characterized by FTIR and 1 H NMR spectroscopy, thermogravimetry, viscosity and solubility tests. The inherent viscosity of the polymers was in the range 0.23-0.46 dl g −1 in dimethyl sulfoxide at 30 • C. They dissolved readily in polar solvents at room temperature. They possess a glass-transition temperature in the range 210-260 • C and exhibit excellent thermal stability.

Synthesis and characterization of new soluble and thermally stable poly(amide‐imide)s containing pendent benzimidazole moieties

“…Various synthetic methods for the preparation of poly(amide‐imide)s (PAIs) have been disclosed in many reports. One of the convenient and efficient synthesis of high‐molecular weight PAIs is the direct polycondensation of imide‐containing dicarboxylic acids with aromatic diamines by means of the Yamazaki–Higashi phosphorylation technique,14 developed by one of us 15, 16. The direct polycondensation route is a very useful laboratory method and avoids using moisture‐sensitive acid chlorides or isocyanates 17–19.…”