Abstract
A series of thermotropic liquid crystalline phosphorus-containing copolyesters was prepared by polycondensation reaction starting from various ratios of 2-(6-oxido-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)-1,4-benzene diol, 1, terephthaloyl bis-(4-oxybenzoyl-chloride), 2, and, 1,12-dodecanediol, 3. The molar ratio of aromatic bisphenol to aliphatic diol was varied in order to generate copolyesters with tailored physico-chemical properties. The chemical structure of the synthesized polymers has been confirmed by Fourier transform infrared and 1H NMR spectroscopy. The phase transitions of the phosphorus-containing copolyesters have been investigated by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction measurements, structure–properties relationships being established and discussed. Keywords: phosphaphenanthrene; phase transitions; structure-property relations