Copyright © 2012 Saeed Zahmatkesh. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

An unsymmetrical heterocyclic dicarboxylic acid monomer, 4-[4-(4-carboxy phenoxy)-naphthyl]-2-(4-carboxyphenyl) phthalazin-1-one (1) was successfully prepared. A series of polyamides containing phthalazinone were prepared from the prepared dicarboxylic acid with various aromatic diamines in an ionic liquid (IL) as a green, safe, and eco-friendly medium and also reactions catalysis agent. Evaluation of data shows that IL is the better polyamidation medium than the reported method and the catalysis stands on the higher inherent viscosities and yields of the obtained PAs and the rate of polymerizations beyond the greener reaction conditions and deletion of some essential reagents in conventional manner. Characterization was performed by means of ¹H-NMR and FT-IR spectroscopy, elemental analysis, thermogravimetric analysis, and differential scanning calorimetric techniques. Molecular weights of the obtained polyamides were evaluated viscometrically, and the measured inherent viscosities were in the range of 0.46–0.71 dL/g. These polyamides were readily soluble in many organic solvents. These polymers still keep good thermal stability with high glass transition temperatures in the range of 310–345^∘C and the decomposition temperature under the nitrogen atmosphere for 10% weight-loss temperatures in excess of 488^∘C.