SYNTHESIS AND CHARACTERIZATION OF LIQUID-CRYSTALLINE POLYESTERS BASEDON BIPHENYL-4,4'-DIOL

The syntheses of liquid-crystalline polyesters of biphenyl-4,4'-diol a nd 1,4-butanediol with adipic acid were carried out by varying the mol e ratios of the two diols, keeping the total mole ratio of diacid to d iols constant. Adipic acid was first converted into adipoyl dichloride , which was then reacted with the diol(s) in dimethylformamide. The re sultant polyesters were characterized by means of H-1 NMR and FT-IR sp ectroscopy, elemental analysis, thermogravimetric analysis and gel per meation chromatography. The liquid-crystalline behavior of the polyest ers was studied by differential scanning calorimetry and hot-stage pol arization microscopy.