NOVEL WHOLLY AROMATIC LYOTROPIC LIQUID-CRYSTALLINE POLYESTERS - SYNTHESIS, CHARACTERIZATION, AND SOLUTION PROPERTIES

Three wholly aromatic polyesters containing sulfonate pendent groups have been synthesized by an interfacial polycondensation technique from hydroquinonesulfonic acid potassium salt and diacid chlorides. These polymers were characterized structurally using FTIR and solid-state CP/MAS C-13 NMR. They show varying degrees of solubility in aqueous DMSO and aqueous DMF and are most soluble in 1:1 DMSO/H2O. Viscosity measurements of dilute solutions at concentrations less than 0.5 g/dL show a polyelectrolyte effect. The solution-phase behavior of these polyesters has been studied microscopically using aqueous DMSO, aqueous DMF, and pure DMSO, DMF, and water as solvent under crossed polarizers. Polymer 3 with a nitro group on the diacid unit shows lyotropic liquid crystal behavior in these solvent systems except in pure DMSO. The critical concentration required for formation of an anisotropic solution falls as the water content in aqueous DMSO solution increases. These polyesters decompose upon heating at high temperature and do not show thermotropic liquid crystal transitions in the solid state.