Linear precursors of liquid crystalline thermosets

Abstract

Polycondensation of glutaric acid with a diglycidyl terminated mesogenic molecule [p-(2,3-epoxypropoxy)-α-methylstilbene] was carried out with a basic catalyst. A variety of novel main chain thermotropic liquid crystal oligoesters were synthesized via a short melt-copolycondensation process, by using different ratios of co-monomers. Preliminary studies by thermogravimetric analysis, differential scanning calorimetry, steric exclusion chromatography and Fourier transform infrared spectroscopy have been carried out on the reacting mixtures in order to optimize the reaction conditions (temperature, time). Carbon-13 nuclear magnetic resonance was used to identify the material structure. The mesophase stability ranges of the oligoesters were evaluated by means of DSC and optical polarizing microscopy. X-Ray diffraction analysis was applied to determine the nature of the mesophase.