The Design And Preparation Of A Novel Diacid

Liquid crystal polymer materials there are excellent mechanical properties, which make them useful as high-performance materrials for advanced technologies. In 21th centry, thermotropic polyamides are broadly attended by the boffins of polymer and materials science. To the study of main chain thermotropic liquid crystal polyamides,designing novel diacids is the emphamses.In this study, according to the liquid crystal forming theory we have designed a novel diacid(Polyethyleneglycal Bis(4-carboxyphenyl)ether, PEGa) with 4 ethers and 2 benzenes. A kind of polyamide synthesized by us, which includes the novel diacid, has a stable liquid crystal phase. The range of this liquid crystal polyamide is 66癈. Then using IR analyzes the structures, and using DSC, PLM characterizes their quality of liquid crystal.In this thesis, we have also studied the factors affecting the synthesis process deeply, such as the type of carbonates, the ratio and concentration of fluxing solution and the fluxing temperature. In laboratory, we can synthesize PEGs from 1.5g to 55g in one experiment, the refine yield of the medium product can be stable above 90%, and the fluxing yield is 96-98%. At the same time, we have resolved the key issues of the system changing color and che reaction speed being too rapid when fluxing.