Liquid crystalline aromatic alkylene polyesters with biphenylylene groups in the mesogen

Abstract Novel diacid dichlorides were prepared from biphenyl derivatives and used for synthesizing—by high-temperature condensation of the dichlorides with aliphatic or oxyaliphatic diols—two series of aromatic thermotropic LC polyesters, differing in the phase transition temperatures and breadths of the mesomorphic intervals. Stability of the polymeric mesophase was found to be enhanced by the introduction of 4,4′-biphenylylene group and depressed by the 2,5-biphenylylene moiety.