Comparative study of new thermotropic polyazomethines

Abstract

Abstract Three series of novel modified polyazomethines were prepared with mesogenic units and varying kinking groups. The effect of the incorporation of the kinking groups on the thermotropic properties of the alternated and random polymers was studied. Structural elucidation was carried out by elemental analysis, infrared (IR), proton nuclear magnetic resonance ( 1 H‐NMR) and UV‐vis spectroscopy. Inherent viscosity of the polymers measured in N , N ‐dimethyl formamide (DMF) at 20°C was in the range 0.15–0.44 dl/g. Their molecular weight and molecular weight distribution were determined using gel permeation chromatography (GPC). Mesomorphic properties were studied by differential scanning calorimetry (DSC), hot stage polarizing optical microscopy and the thermal stability was determined by thermogravimetric analysis (TGA). Some polyazomethines exhibited fine grain texture and good mesophase stability. It was observed that the random copolymers had lower melting point and higher mesophase stability than alternated polymers. Copyright © 2006 John Wiley & Sons, Ltd.