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LIQUID CRYSTALLINE POLYMERS. 3. SYNTHESIS AND LIQUID CRYSTAL PROPERTIES OF THERMOTROPIC POLY(ARYLIDENE-ETHER)S AND COPOLYMERS CONTAINING CYCLOALKANONE MOIETY IN THE POLYMER BACKBONE

Two novel series of poly(arylidene-ether)s and copoly(aryl-idene-ether)s were synthesized by polycondensation of 4,4′-diformyl-α,ω-diphenoxyalkane and 4,4′-diformyl-2,2′-dimeth-oxy-α,ω-diphenoxyalkane with cyclohexanone and/or cyclo-pentanone. The inherent viscosity of the polymers and copolymers thus prepared were in the range of 0.42–1.27 dL/g. The phase behavior of these polymers was studied by differential scanning calorimetry (DSC), optical polarizing microscopy using a heated stage, and thermogravimetric analyses. Almost all the polymers and copolymers exhibited thermotropic liquid crystalline properties. In most cases, the mesophase extends up to 310°C, where thermal decomposition prevents further observation. Methoxy substituents, on the benzene ring of these polymers, lower the transition temperature significantly. The morphology of polymer IXf was examined by scanning electronic microscope.