On the motion of the mesogenic unit in liquid-crystalline polyesters.
Liq.-cryst. polyester-siloxanes were studied by high-resoln. solid-state C-13 NMR spectroscopy. Expts. were performed at various temps. in the solid and mesomorphic phase. The results of a spinning sideband anal. provided proof that in all systems investigated a motion of each of the 3 rings of the p-terphenyl group sets in at 5-10 Deg below the m.p. (transition solid -> liq.-cryst.). A flip of the arom. rings over 45-50 Deg was also evidenced.
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