Synthesis and characterization of liquid crystalline copolyesters containing horizontal and lateral rods in main chain (II)

A series of liquid crystalline copolyesters, possibly having auxetic behaviour, were designed and synthesized by solution polycondensation from 4,4′-(decanoxy) dibenzoyl chloride with 2,5-bis(p-alkoxy benzoyloxy) hydroquinone and 4,4′-dihydroxy-α,ω-diphenoxydecane in different ratios. All the polymers have lower melting point ranging from 80 to 140 °C, which is beneficial to the liquid crystalline state formation and the thermoplastic processing. The lateral rods derived from 2,5-bis(p-alkoxy benzoyloxy) hydroquinone monomer gave an obvious influence on properties of the resulting polymers, in which the liquid crystalline state stability and the solubility in common organic solvents were enhanced. Observations from POM and DSC indicated that all the polymers are thermotropic liquid crystalline with nematic characteristics.