Synthesis and X-ray Characterization of Alkoxy-Substituted Aromatic Polyesters Containing Terphenyl or Quinquephenyl Units in the Main Chain

Soluble aromatic polyesters derived from 2‘,5‘-dialkoxy- p -terphenyl-4,4‘-diols or 2‘‘,5‘‘-didodecyloxy- p -quinquephenyl-4,4‘‘‘‘-diol and terephthaloyl or 2,5-dialkoxy-terephthaloyl dichlorides were prepared. The polymers were characterized by viscosimetry, thermal analysis, and X-ray diffraction. The polyesters show two or more endothermic transitions. The high-temperature transitions to an isotropic melt moved to lower temperatures as the side chain length increased. Structural information was obtained from the temperature-dependent X-ray data. Various structures were observed depending on the type of the phenylene segment in the backbone, the length of alkoxy side chains, and the number of side chains per backbone repeat unit.