含长烷烃尾链苯并菲侧链液晶高分子的合成及相行为研究

发布时间：2018-06-27 13:45

  本文选题：苯并菲侧链型液晶高分子 + 空间效应　； 参考：《湘潭大学》2017年硕士论文

【摘要】：近年来,苯并菲侧链型液晶高分子(Tp SCLCPs)的液晶机理受到了广泛的关注,越来越多的研究表明Tp SCLCPs的相行为有着独特的液晶机理。但是,科研工作者较少研究苯并菲的空间效应对侧链型高分子相行为的影响。对此,该文通过增长苯并菲的烷烃尾链长度,以此增加苯并菲盘状侧基的固有空间体积(本身分子结构所具有的体积)。本文从主链类型和间隔基长度这两个方面来调控苯并菲盘状侧基对主链空间效应的强弱,通过DSC,POM,1D/2D WAXD和SAXS全面考察侧基空间效应的强弱对Tp SCLCPs相行为和相结构的影响。主要的研究如下:1.设计并合成了一系列不同主链结构的无柔性间隔基长烷烃尾链Tp SCLCPs。通过1H NMR和质谱确定单体的化学结构。通过DSC、POM、1D/2D WAXD和SAXS对其相行为和相结构进行一系列的表征。其研究结果表明,不同主链结构对液晶高分子的相行为有着重要的影响。由于侧基强大的空间效应以及主链与苯并菲侧基之间的耦合作用,所有聚合物都能形成由主链和侧基一起构筑的柱状结构,但是他们的柱状的排列方式会随主链的变化而变化,当主链为聚苯乙烯醚类(POTP)以及聚降冰片类时(PNVTP),聚合物表现为六方柱状相。以聚甲基丙烯酸酯类(PMMTP)和聚丙烯酸酯(PMTP)为主链的聚合物形成柱状向列相。以聚苯乙烯酯类(PSTP)为主链时形成四方柱状相。此外,清亮点(Ti)的温度也会随着主链的变化而变化,通过观察,发现PMMTP的超过300℃。2.设计并合成一系列不同间隔基长度的长烷烃尾链Tp SCLCPs,简称为P-m-TP(m为其间隔基亚甲基的个数,m=2、3、4、6和8)。通过1H NMR和质谱确定单体的化学结构。通过DSC,POM,1D WAXD和SAXS对其相行为和相结构进行表征。实验结果表明:侧基空间效应,去偶合效应和π-π堆积效应的强弱依赖于间隔基长度的变化。当间隔基为2和4时,聚合物在高温形成由主链和侧基一起构筑的柱状向列相,在低温形成四方柱状相;当间隔基为3时,在整个液晶温度范围内,聚合物只能形成柱状向列相。且对于这些聚合物,它们的Ti均大于300℃,表现出甲壳型液晶高分子的特性。这些结果表明,即使间隔基较长,侧基空间效应依然诱导主链和侧基一起形成柱状结构。当间隔基m=6和8时,聚合物形成由侧基苯并菲堆积的六方柱状相,其Ti分别为108℃和84℃,表现出普通的侧链型液晶高分子的性质。这些结果表明,去耦合作用和Tp的π-π堆积作用强于空间效应,聚合物形成由Tp堆积的柱状相。
[Abstract]:In recent years, the liquid crystal mechanism of benzphenanthrene side-chain liquid crystal polymers (TP SCLCPs) has been paid more and more attention. More and more studies show that the phase behavior of TP SCLCPs has a unique liquid crystal mechanism. However, researchers seldom studied the effect of the spatial effect of benzophenanthrene on the behavior of side chain polymer phase. In this paper, by increasing the length of the alkane tail chain of benzphenanthrene, the intrinsic space volume (the volume of its molecular structure) of the disk-like side group of benzophenanthrene is increased. In this paper, the main chain type and spacer length are used to regulate the spatial effect of the disklike side group on the main chain. The effects of the side base spatial effect on the phase behavior and phase structure of TP SCLCPs are investigated by DSCP POMN 1D / 2D WAXD and SAXS. The main research is as follows: 1. A series of flexible spacer tail chain (TP SCLCPs) with different main chain structures have been designed and synthesized. The chemical structure of the monomer was determined by 1H NMR and mass spectrometry. The phase behavior and phase structure were characterized by DSC-POMN 1D / 2D WAXD and SAXS. The results show that the phase behavior of liquid crystal polymers is affected by different main chain structures. Due to the strong spatial effect of the side group and the coupling between the main chain and the benzofen side group, all polymers can form columnar structures constructed by the main chain and the side group, but their columnar arrangement will change with the change of the main chain. When the main chain is polystyrene ether (POTP) and polynorborneol (PNVTP), the polymer exhibits hexagonal column phase. Poly (methacrylate) (PMMTP) and polyacrylate (PMTP) were used to form columnar nematic phase. The tetragonal columnar phase was formed when polystyrene esters (PSTP) were used as main chain. In addition, the temperature of the clear bright spot (Ti) also changes with the change of the main chain. Through observation, it is found that the PMMTP is more than 300 鈩，

本文编号：2074111