FULLY AROMATIC THERMOTROPIC LIQUID-CRYSTALLINE HOMOPOLYESTERS OF 3,4'-BENZOPHENONE DICARBOXYLIC-ACID

A series of fully aromatic, thermotropic homopolyesters, derived from 3,4'-benzophenone dicarboxylic acid and various aromatic diols, was prepared by the melt polycondensation method and examined for thermotropic behavior by a variety of experimental techniques. The aromatic diols used in the study were hydroquinone, 2,6-, 1,4-, 1,5-, 2,3-, and 2,7-naphthalenediol isomers. All of the homopolyesters of 3,4'-benzophenone dicarboxylic acid with aromatic diols (except that with 2,7-naphthalenediol) formed a nematic LC phase in the melt. They had the glass transition temperatures (T-g) in the range of 133-164 degrees C, the melting transitions (T-m) in the range 305-360 degrees C and the high thermal stabilities (T-d) in the range of 410-483 degrees C. The 2,6-naphthalenediol based homopolymer had the highest T-m (360 degrees C) and the 2,3-naphthalenediol based homopolymer had the lowest T-m (305 degrees C) among all of the homopolymers of naphthalenediol isomers. (C) 1994 John Wiley & Sons, Inc.