Synthesis And Characterization Of New Kinds Of Thermotropic Liquid Crystalline Polymers

Two kinds of thermotropic liquid crystalline polymer have been synthesized in this paper. They have not been reported.One is Side-Chain Liquid Crystalline Polymer of PVA. Electron-donating PVA and electron-accepting 4-stibazole through a molecular recognition prepared this Side-chain liquid crystalline polymer. The polymer exhibits thermotropic liquid crystalline behavior with relatively wide temperature scope and low phase transition temperature when the mesogenic 4-stibazole as side chain is directly fixed to the PVA as backbone. The hydrogen bonds reduce the interaction between the mesogenic side chains and backbones inducing the stabilization of liquid crystalline behavior.The result of the study of Side-Chain Liquid Crystalline Polymer of PVA showed the molecular weight of PVA affects the character of liquid crystalline. The greater molecular makes the rigid moieties introduced to the chain more difficultly, the complex containing more 4-stibazole has the higher stabilization of liquid crystalline phase than the less one. Using Side-Chain Liquid Crystalline Polymer of PVA as nucleating agent, the polypropylene's crystallizing rate is accelerated. The other kind of thermotropic liquid crystalline polymer is hyperbranched polyester. The one-step synthesis of the hyperbranched polyester based upon 3,5-dihydroxy benzoic acid and 3,5-dihydroxy toluene has succeeded in getting hybranched polyester. This kind of hyperbranched polymer has showed to exhibit not only the properties of low viscosity and high solubility but also nematic liquid crystal phase in relatively wide temperature scope from 83.4 to 134.6℃. The result of the study of thermotropic liquid crystalline polymer of the hyperbranched polyester showed that the ratio of mole of react substance and temperature affect the reaction. When the ratio of mole of react substance come to head, the molecular weight of hyperbranched polyester is difficult to increase. Too high temperature makes the product disintegrated. The thermotropic liquid crystalline behavior is relative to the molecular weight of the product of the hyperbranched polyester. In the course of synthesis of hyperbranched polyester copolymer of maleic anhydride is entered into getting microfibre with size of 6μm。...