MAIN-CHAIN CHOLESTERIC LIQUID-CRYSTALLINE POLYESTERS WITH CHIRAL PENDANT GROUPS .1. MODEL COMPOUNDS AND POLYESTERS CONTAINING A CHIRAL SUBSTITUTED HYDROQUINONE

For the design and preparation of new cholesteric liquid crystalline polyesters (ChLCPs) from 2-[(S)-(+)-2-methyl-1-butoxy]hydroquinone as the chiral monomer, an appropriate model compound and the two LCPs containing triad ester mesogenic units and flexible spacers were prepared and characterized by wide-angle X-ray diffraction (WAXD), thermal, and optical methods. The model compound exhibited a monotropic cholesteric liquid crystalline mesophase, while the polymers had enantiotropic liquid crystalline mesophases, but the liquid crystalline temperature ranges were relatively narrow. In addition, the annealing process enhanced the degree of crystallinity and T(m) of the crystalline phase; then the enantiotropic mesophase of the polymers was converted into the monotropic mesophase. The textures of both polymers in the liquid crystalline state did not develop to those expected for a cholesteric phase. WAXD indicated that the patterns for both crystalline polymers could be indexed in an orthorhombic unit cell.