聚硅氧烷侧链胆固醇酯液晶聚合物的合成及性能研究

Synthesis and properties of polysiloxane side-chain cholesteric ester liquid crystal polymer

设计、合成了一种烯丙氧基联苯甲酸胆固醇酯液晶单体(V1OBEG),并通过巯基-乙烯基点击加成反应,将其接枝到聚(3-巯丙基甲基硅氧烷)(PMMS)上,得到一种新型的以聚硅氧烷为主链的侧链高分子液晶(PMMS-V1OBEG)。通过红外光谱、核磁共振氢谱、差示扫描量热仪和偏光显微镜分别对液晶单体和聚合物的分子结构及液晶行为进行表征。结果表明,液晶单体的熔点和清亮点分别为189.37℃和277.99℃,在升温过程中先后出现胆甾相的玫红色油丝织构和蓝色油丝织构,继续升温时呈指纹织构,降温过程中出现焦锥织构;聚合物的玻璃化转变温度和清亮点分别为103.71℃和278.16℃,在升温过程中出现胆甾相液晶,降温过程中无液晶相。

A allyloxy biphenyl acid cholesterol ester liquid crystal monomer(V1OBEG) has been synthesized,which is grafted onto PMMS side chain through thiol-ene click reaction,and a novel polysiloxane cholesteric ester liquid crystal polymer(PMMS-V1OBEG) with polysiloxane as the main chain is obtained successfully.Their chemical structure and liquid crystal behaviors are characterized by FTIR, 1H NMR,DSC,and POM.The results suggest that T m and T i of the monomer are 189.37 ℃ and 277.99 ℃,respectively,and the monomer displays successively rose-red oil silk texture,blue oil silk texture,and finger-like texture of the cholesteric phase in the process of heating up,while the focal conic texture is formed in the process of cooling down;T g and T i of the polymer are 103.71 ℃ and 278.16 ℃,respectively,and the polymer shows cholesteric phase during the heating process,but there is no liquid crystal phase appearing during the cooling process.