WHOLLY AROMATIC THERMOTROPIC LIQUID-CRYSTALLINE POLYESTERS OF 4,4'-BIPHENOL, SUBSTITUTED BIPHENOLS, AND 1,1'-BINAPHTHYL-4,4'-DIOL WITH 3,4'-BENZOPHENONE DICARBOXYLIC-ACID

Wholly aromatic, thermotropic homopolyesters, derived from 4,4'-biphenol, substituted biphenols, or 1,1'-binaphthyl-4,4'-diol and 3,4'-benzophenone dicarboxylic acid, and two copolyesters, each of which contained 30 mol % of 6-hydroxy-2-naphthoic acid, were prepared by acidolysis polycondensation reactions and characterized for their liquid crystalline properties. The solubility behavior of these polymers has also been investigated. The two homopolymers of phenyl-substituted biphenols with 3,4'-benzophenone dicarboxylic acid were soluble in many common organic solvents. All of the homopolymers had lower T-m/T-f values than those with terephthalic acid, which was attributed to the incorporation of the asymmetric 3,4'-benzophenone dicarboxylate units in a head-to-head and head-to-tail fashion along the polyester chain. Two copolymers had lower T-m values than those of the respective homopolymers, as expected. They formed nematic phases which persisted up to 400 degrees C, except those of phenyl-substituted biphenols with 3,4'-benzophenone dicarboxylic acid. Each of these two polymers also exhibited an accessible T-i transition, and had a broad range of LC phase. They had glass transition temperatures, T-g, in the range, of 139-209 degrees C and high thermal stabilities in the temperature range of 465-511 degrees C. (C) 1995 John Wiley and Sons, Inc.