LIQUID-CRYSTALLINE AROMATIC POLYESTERS CONTAINING PARA-LINKED DIMETHYLBIPHENYLENE MOIETIES

A series of liquid crystalline aromatic polyesters containing 3,3'-dim ethylbiphenyl-4,4'-dicarboxylic acid and 3,4'-dimethyl-biphenyl-4,3'-d icarboxylic acid was prepared by a melt polycondensation procedure and characterized by elemental analysis, DSC and TMA measurements, and op tical polarizing microscopy. An optimal composition of the copolymer h aving a melting temperature around 300 degrees C is proposed and the r heological behavior is discussed. Most of the mechanical properties of this copolymer were found to be close to those of Vectra A950(R) used as a reference sample. (C) 1996 John Wiley & Sons, Inc.