Synthesis And Performance Characterization Of Thermotropic Main Chain Liquid Crystalline Polyurethane

In this thesis,some theoretical knowledge about liquid crystalline polymer (LCP) and thermoplastic polyurethane elastomers(TPU) were introduced,including their founding,different classification methods,the nature of different state, application and synthesis, and It especially was focused on that the current status and development trend of domestic and foreign research and the function of liquid crystalline polymer as composite materials.The experiments were designed two LCPU elastomer system synthesis route and a novel thermoplastic polyurethane elastomer synthetic route. They were characterize-ed by FT-IR, DSC and POM (hot and cold table) respectively. And the tear strength, tensile strength, Shore A hardness and rheology of novel TPU were tested.The first system used the hydroquinone and2,4-toluene diisocyanate (2,4-TDI),1,2-ethylene glycol (EG),1,4-butanediol (BDO),1,6--hexanediol, diethylene glyc-ol and triethylene glycol as the basic raw material. They were synthesized by a two-step reaction method, and finally obtained polyurethane elastomer products which were named PU1,PU2,PU3,PU4and PU5.Experimental results show that there are two absorption peaks in the DSC curve of PUl, PU2, PU3,while PU4and PU5have only one. However,none ofthem can observe the liquid crystal.The second system used MDI instead of TDl,and repeated the last experiment.Its results show that M-2and M-3all could observe the liquid crystal.The third system is based on PTMG, diphenyl methane diisocyanate, methylparaben, terephthaloyl chloride and1,4-butanediol as the basic raw materials. Induced crystal primitives using a two-step method. Experimental results show that the novel polyurethane elastomeric properties induced crystallization primitives has a better performance than that did not. These physical properties incerases as the increase of the content of induced crystallization primitives.And their DSC curve has two peaks.