Synthesis and Characterization of Liquid Crystal Polyesters with T-Shaped Two-Dimensional Mesogenic Units(III)
writer：Z.F.Li, L.Li, S.Y.Zhang, S.J.Zheng and S. K. Cao,
keywords：T-shaped two-dimensional mesogenic units, Liquid crystal polyester,Synthesis and characterization
source：期刊
A new series of liquid crystal polyesters with T-shaped two-dimensional mesogenic units were synthesized by melt polycondensation of the diacetates of 2-(4`-alkoxy-phenyl)-hydroquinones with 4,4`-alkylenedioxydibenzoic acid. The polymers were characterized by usin polarized microscopy,DSC and X-ray diffraction.It was relized that all the polymers have nematic thermotropic liquid crystalline characteristics.The melting temperature (Tm) and isotropization temperature (Ti) of the polymers change regularly with varying lengths of the alkoxy side group and the length of the alkylene group in the main chain in company with an even-odd effect. The mesophase temperature range also varies regularly with the polymer structure. It is shown that the mesophase range has been widened.