Thermotropic Copolyesters Containing the Bicyclo [2.2.2]Octane Ring System

Abstract

A number of thermotropic copolyesters which contain the bicyclo[2.2.2]octane and bicyclo[2.2.2] oct-2-ene ring systems have been synthesized. In order to decrease the melting temperatures to below the decomposition points, the following approaches were used: (1) sebacoyl flexible spacers; (2) ethylene glycol and 1,4-butanediol to form flexible spacer units; (3) trans-1,4-cyclohexylene dimethylene, 1,4-bicyclo[2.2.2]octylenedimethylene and 1,4-phenylenedimethylene semiflexible spacers; and (4) the lower symmetry bicyclo[2.2.2]oct-2-ene ring system as a replacement for the bicyclo[2.2.2]octane ring system. The polycondensation of terephthaloyl chloride and bicyclo[2.2.2]oct-2-ene-1,4-diol resulted in the formation of a thermotropic homopolyester.