Structure-order relationships in liquid crystalline polyesters

Abstract

-Several series of polyesters containing mesogenic groups based upon aromatic ester triads and polymethylene flexible spacers have been prepared and characterized for their liquid crystalline properties in the melt. The relationships between repeating unit structure and the type of mesophases formed, as well as their transition temperatures and other thermodynamic properties, are discussed for both these main chain, liquid crystalline polymers and their model compounds. Particular consideration is given to the effects of small variations in the triad ester sequences, substituent effects and aspect ratio of the mesogenic group on thermotropic properties.

Structures of di-p-tolyl terephthalate (C22H18O4) and 1,4-phenylene di-p-toluate (C22H18O4)

“…The title compounds are both mesogenic. They are characterized by the atomic groups A = --~--OOC--~p--COO---~--and B = --q~---COO---~---OOC--qr--(--qr--= p-phenylene) that have been extensively utilized in the synthesis of low-molecular-weight mesogenic compounds (Dewar & Goldberg, 1970;Schroeder & Bristol, 1973;Kelker & Hatz, 1980) and polymeric (Lenz, 1985) mesogenic compounds.…”