Thermotropic mesomorphic polyesters. I. Copolyesters of terephthalic acid,hydroquinone, and flexible diols

A new series of copolyesters has been synthesized by low-temperature solution polycondensation of terephthaloyl dichloride hydroquinone and flexible diols such as 1,2-propane diol, 1,4-butanediol, diethylene glycol, (cis) 1,4-cyclohexanediol and (cis + trans) 1,4-bis(hydroxymethyl) cyclohexane. The copolyesters are all insoluble and display thermotropic mesophases at relatively lower transitions than other commercially important systems. The transition temperatures, the crystallinity, and thermal characterization are reported.