THERMOTROPIC LIQUID CRYSTALLINE POLY( beta -THIOESTER)s.

Recently, the authors described the synthesis and characterization of thermotropic poly( beta -aminoester)s containing the azoxy group as a typical chemical function within a mesogenic moiety. As a continuation of the interest in establishing structure-property correlations for mesomorphic linear polymers displaying thermotropic behavior, attention has been addressed toward poly( beta -thioester)s having the same rigid mesogenic core, i. e. , the azoxybis(1,4-phenylene) unit, connected in a linear polymer matrix via alpha , OMEGA -dicarboxylate moieties of different structure, which contain two bivalent sulfur atoms symmetrically placed in beta position to the carboxylate groups. Data are presented which show that replacement of the nitrogen atoms by sulfur atoms in the corresponding poly( beta -aminoester)s leads to polymeric materials that are characterized by a higher degree of thermal stability, and at the same time exhibit the occurrence of mesomorphic phases in the melt with rather wide ranges of existence.