CONFORMATION, ORDERING AND MOBILITY OF MACROMOLECULES IN AROMATIC POLYESTERS AS STUDIED BY IR AND SOLID-STATE NMR-SPECTROSCOPY

Thermotropic main-chain LC polyesters have been studied with the aid o f IR and NMR spectroscopy. Rigid mesogens and mesogens with a possibil ity of conformational isomerism were examined. The dependence of the o rder parameters of the mesogens and spacers on the chemical structure of the polymer has been determined. The IR spectroscopy data and the d ata of the calculation of the possible conformations of the mesogen an d the spacer confirm the theoretical predictions about the straighteni ng of macromolecules in the anisotropic melt. Solid-state H-2 NMR spec tra show that p-oxybenzoic rings adjacent to a flexible spacer are mor e mobile than inner terphthalic rings. In decamethylene spacer the con trary holds true: the mobility of inner methylene groups is more marke d than that of the alpha-methylene groups bound to the mesogen.