Thermotropic polyesters with alkylene spacers in the main chain prepared in diphenyl ether

A series of linear thermotropic polyesters derived from 4,4'-dihydroxy-alpha,omega-diphenoxy, alkanes and 4,4'-dichloroformyl-alpha,omega-diphenoxy alkanes, was prepared by polycondensation in diphenyl ether. This method yielded polyesters that were characterized by a wider persistence range of the nematic phase with respect to the corresponding polyesters prepared by a conventional technique. The linear polyester series was characterized by calorimetric, optical microscopy: and, thermogravimetric measurements. The linear thermotropic polyester series formed a stable nematic liquid crystalline phase in the melt and presented high thermal stabilities in the range of 410-449 degrees C.