侧链含有蓝相液晶基元的聚硅氧烷液晶的合成及表征

摘要

A side-chain liquid crystalline polysiloxane with two blue-phase mesogenic monomers：trans-4-vinyl-trans-4′-propylbicyclohexyl and trans-4-propenyl-trans-4′-propylbicyclohexyl exhibiting mosaic and oil grain textures was synthesized.The chemical structures of the obtained polymers were confirmed by FT-IR and 1H-NMR spectroscopy.Their mesomorphic properties and phase behavior were investigated with POM,DSC,TGA and X-ray measurements.The temperature ranges of mesogenic phase of 3HHV and 4HHV are 30.6 °C and 49.7 °C,respectively,and they exhibit mesomorphic phase below room temperature.The polymer exhibits grain shadow texture phase,decomposition temperature（at 5% mass loss） is more than 310 °C,and the temperature ranges of mesogenic phase is 192.6 °C.They also exhibit mesomorphic phase below room temperature.The thermal stability is much higher than other side-chain liquid crystalline polysiloxane with non-aromatic mesogenic monomer.%采用蓝相小板块液晶单体反式-4-乙烯基-反式-4′-丙基双环己烷（3HHV）和反式-4-丙烯基-反式-4′-丙基双环己烷（4HHV）同时接枝到聚甲基含氢硅氧烷上,制备了聚硅氧烷侧链液晶聚合物。采用红外光谱和核磁共振氢谱对液晶单体及相应的聚合物进行结构表征,采用热台偏光显微镜,X-射线衍射和热分析对单体和聚合物的液晶行为及热性能进行研究。结果表明：液晶单体3HHV显示蓝相镶嵌织构,液晶单体4HHV显示胆甾相油纹状织构,它们的介晶区间温度分别为30.6°C和49.7°C,且均在低于室温就显示出液晶性。相应的液晶聚合物显示向列相纹影织构,介晶区间温度为192.6°C,在低于室温时也显示出液晶性,且热分解温度达到310°C以上,比其他环芳烃类介晶基元接枝聚硅氧烷主链的液晶聚合物具有更优越的热稳定性。