Polycondensation of metal salts of 6-(2-chloroacetate)hexanoic acid: A new method to synthesize alternating copolyesters constituted by glycolic acid units

摘要

A new copolyester was prepared from glycolic acid and 6-hydroxyhexanoic acid units. The monomer was prepared by a thermal polycondensation method and its reactivity evaluated by means of DSC and IR spectroscopy. The driving force of the reaction was the formation of a metal chloride salt. Thus, the reactivity depended on the ionization potential of the alkaline cation; while the cesium salt started to polymerize at room temperature, the sodium salt did so only above 120 degrees C. The low reaction temperature and the absence of catalysts allowed trans esterification and other secondary reactions to be avoided. DSC, optical microscopy and XRD techniques demonstrated that the new polymer was highly crystalline. The final molecular weight was sufficient to obtain fiber-forming properties.