MOLECULAR-MOTION AND ORIENTATION DISTRIBUTIONS IN MELT-PROCESSED, FULLY AROMATIC LIQUID-CRYSTALLINE POLYESTERS FROM H-1-NMR

Fully-aromatic thermotropic liquid crystalline polymers (LCP) containi ng 4-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA) we re studied with H-1 NMR. A two- or three-parameter nematic director di stribution in molten or nearly molten samples was obtained via rigorou s simulation of wideline spectral lineshapes. This methodology was fur ther employed to yield the chain director distribution in macroscopic sections derived from a frozen contraction flow. In addition, the dyna mic conformation of polymer chains through the melting transition was monitored via lineshape analysis of samples having (bulk) isotropic di rector distributions. Extension of rigorous H-1 NMR spectral deconvolu tion to recently developed solid-state NMR imaging sequences is discus sed. (C) 1998 Elsevier Science B.V. All rights reserved.