Liquid Crystalline Polymers

Abstract

In this article emphasis will be placed on selectively from 45 papers presented at the spring meeting and 33 papers also presented at the fall meeting.     

Ferrocene-containing Liquid Crystalline Polymers

This article is one of a number of reviews in a special issue to honor Prof. Dr. Ian Manners of the University of Bristol, UK, for his outstanding contributions in the field of organometallic polymers. The focus of this review is on the syntheses, properties, and characterization of ferrocene-containing liquid crystalline polymers in which ferrocene moieties are in or pendent to the backbone and also dendrimers and [60]fullerene-ferrocene liquid crystalline materials.     

功能液晶聚酯

综述了新型功能液日聚酯材料的大分子链结构、液晶相变温度与应用前景。这类功能液晶聚酯或者其主链含有大量碳碳双键,或者其侧链上含有大量氟碳链节或偶氮链节。功能液日聚酯的玻璃化转变温度和液日相变温度通常比传统高强度、高模量液日聚酯要低,尤其具有高强度、高模量液晶聚酯所不具备的特殊性能,如交联化、凝胶和感光作用,使其可以作为全息储存膜和其他功能材料。     

胆甾醇乙酸酯液晶的合成

采用胆甾醇与乙酸酐直接酯化法合成胆甾醇乙酸酯，优化后的工艺条件为：n(乙酸酐)：n(胆甾醇)＝1．9-2．0：1，反应温度80℃，反应时间3h，在此条件下，产率可达95％以上；经无水乙醇重结晶，纯度达99％以上。产品的熔点为97．5℃，清亮点为113℃，IR谱图分析和元素分析结果表明，产物纯度较高。     

热致液晶聚合物的热增强及应用

基于各种正式发表的文献 ,澄清了热致液晶聚合物发展过程中的一些问题 ,并对各种形式热致液晶聚合物的热增强属性作一系统阐述。     

液晶聚氨酯研究进展

介绍目前国内外液晶聚氨酯的研究和发展状况,着重介绍液晶聚氨酯的合成、结构与性能及其相关的影响因素,展望了液晶聚氨酯的发展趋势。     

Thermal Imidization of the Precursor of a Liquid Crystalline Polyimide

Imidization of the precursor of a liquid crystalline polyimide was investigated using modulated differential scanning calorimetry (MDSC), Fourier transform infrared (FTIR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), and thermogravimetric analyzer (TGA) coupled to FTIR (TG‐IR). The FTIR study revealed that the rate and degree of imidization are functions of curing temperature and time. Imidization proceeds in two stages under isothermal condition. The initial weight loss up to 250 °C as observed from TGA was due to thermal cyclization, i.e., imidization process. The XPS analysis shows that the poly(amic acid) has two nitrogen 1s species at 400.3 and 399.2 eV possibly due to the isomerism of the dianhydride carbonyl, while liquid crystalline polyimide shows only a single nitrogen 1s species at 400.8 eV due to imide species.

PLM micrograph of PAA (at 280 °C) after imidization.     

一种新型液晶环氧树脂单体的合成与固化研究

合成了一种新型复合联苯和芳香酯型的液晶环氧单体(4,4'-双(4-羟基苯甲氧基)-3,3,5,5'-四甲基联苯二缩水甘油醚,DGE-BHBTMBP),并用FT-IR、1H-NIVlR和13C-NMR对产物进行结构表征.用4,4'-二氨基二苯基砜(DDS)和4,4'-双(氨基苯氧基)二苯砜(BAPS)两种芳香二胺固化剂在DSC中进行等温和非等温固化研究,从固化过程来看,BAPS比DDS更适合作为DGE-BHBTMBP的固化剂.     

液晶的织构与表征

液晶具有晶体分子排列的有序性和光学各向异性,液晶独特性在于它对外界因素如热、磁、光等都非常敏感,使其结构发生变化,其功能也发生相应的变化。在当今科技中有着非常广泛的应用。本文对液晶的分类,液晶的织构和液晶的表征方法及手段等方面进了具体的阐述。     

新型液晶离聚物研究进展

液晶离聚物是一种具有液晶聚合物和离子聚合物双重特性的一类高聚物.液晶离聚物不仅显示溶致和/或热致液晶性,而且具有一些特殊的功能性.本文基于国内外最新研究文献,论述近年来合成的五类液晶离聚物的液晶行为及应用前景.     

Formation of Liquid Crystalline Order and Its Effect on Thermal Conductivity of AlN/Liquid Crystalline Epoxy Composite

The liquid crystalline (LC) order was introduced on aluminum nitride particles by the surface effect to increase the thermal conductivities of aluminum nitride/LC epoxy composites. X-ray diffraction and grazing incidence small-angle X-ray scattering analyses revealed that the LC epoxy resin cured on the surface of an α-Al₂O₃ substrate formed homeotropically aligned smectic layers to increase the thermal conductivity. Therefore, thermally treated aluminum nitride particles, which formed α-Al₂O₃ layers on their surfaces, were applied to prepare the composites with high thermal conductivity. The thermal conductivities of the resulting composites were 11–36% higher than those with the composites prepared using untreated aluminum nitride particles.     

Adherence of Liquid Crystalline TDI-Polyurethanes to Steel

Linear liquid crystalline polyurethane (LC-PU) were synthesized by the reaction of 2,4-toluene diisocyanate (TDI), 4,4'-bis-(6-hydroxyhexoxy)biphenyl (BHHBP), and poly(butylene adipate) (PBA). The BHHBP as mesogenic unit was incorporated into the hard segment formed by the reaction with the TDI. The hard segments are incompatible with the PBA soft segments. The mesomorphic behaviour is influenced by both the soft segment length and the hard segment concentration.

The adhesion of such polyurethanes used as primer in composites based on steel as substrate and alkyd melamine resin as coating is dependent on the polyurethane structure, the thickness of the polyurethane layer and its drying conditions. The highest wet adhesion stability is achieved by the hard-segment-type polyurethane composed of TDI and the mesogenic unity BHHBP. Partial substitution of BHHBP by 2,2-bis-(hydroxymethyl)propionic acid (BHMPA) in this LC polyurethane enhances the effectiveness of the primer.     

侧链聚硅氧烷液晶中间体的合成

以对羟基苯甲酸、烯丙基溴、含氢硅油为原料,通过取代、硅氢加成反应,合成了柔性连接基为-CH2CH2CH2O-、端基为羧基的侧链聚硅氧烷液晶中间体M1;然后又以对羟基苯甲酸、氯乙醇、丙烯酸和含氢硅油为原料,通过取代、酯化、硅氢加成反应,合成了柔性连接基为-CH2CH2COOCH2CH2O-、端基为羧基的侧链聚硅氧烷液晶中...     

聚氨酯高分子液晶的研究进展

介绍了聚氨酯液晶的研究和发展状况,总结了液晶聚氨酯的合成、影响因素和性能。     

DGEBP液晶环氧树脂的合成研究

以4,4'-二-羟基联苯、环氧氯丙烷及异丙醇为原料,合成了联苯型刚棒状介晶结构的4,4'-二羟基联苯二缩水甘油醚(DGEBP)。采用红外光谱(FT-IR)、核磁共振仪(NMR)对DGEBP的分子结构和液晶性能进行表征,然后将该联苯类液晶与环氧树脂共混制备液晶/环氧树脂复合材料,采用带加热台的偏光显微镜(PLM)及差热扫描量热仪(DSC)等仪器对环氧树脂复合材料进行分析测试,结果表明实验合成出了一种低分子液晶环氧化合物。     

Orientation of Dyes in Liquid Crystalline Media

These two papers form part of a research project investigating the effect of dye orientation in liquid crystalline media. The first paper describes briefly the principles underlying the development of present–day liquid crystal displays, and the second describes a method used for the quantitative investigation of the efficiency of such media in orienting dye molecules (order parameter) in relation to the chemical structure of the dye and the effects of solvent orientation and polarity on absorbance and colour. The data obtained should permit choices of dye to be made to improve visibility and contrast in current liquid crystal display systems.     

胆甾基类液晶聚合物的研究进展

胆甾醇作为一种人们所熟知的天然材料,由于具有生物特性、手性和可作为液晶基元的特征,经常在分子组装中作为骨架材料出现,因而成为当前化学领域和高新技术领域研究的热点之一。本文简要介绍了胆甾基类液晶聚合物的研究进展。     

纤维素在多聚磷酸中的液晶性

讨论了纤维素在多聚磷酸溶液中的溶解情况和液晶性。采用适当的配比,纤维素能够溶解于多聚磷酸并形成各向异性溶液,在偏振光显微镜下可观察到彩色图片。溶液温度、纤维素聚合度、纤维素浓度对液晶性均有影响。溶液受热后,彩色图像会消失。