双对甲氧基苯甲酸甲基对苯二酚酯液晶的合成与测试

以一定摩尔比的对甲氧基苯甲酰氯和甲基对苯二酚,合成双对甲氧基苯甲酸甲基对苯二酚酯,并对其结构进行了元素分析和ＩＲ测定,用差热分析仪和偏光显微镜对其液晶性进行了表征。     

以对甲氧基苯甲酸甲基对苯二酚酯液晶的合成与测试

以一定摩尔比的对甲氧基苯甲酰氯和甲基对苯二酚,合成双对甲氧基苯甲酸甲基对苯二酚酯,并对其结构进行了元素分析和ＩＲ测定。用差热分析仪和偏光显微显镜对其液晶性进行了表征。     

几种热致性向列型液晶材料的合成与测试

以一定摩尔比的对烷氧基苯甲酰氯和对苯二酚钠,在常温常压下反应,合成了双对烷氧基苯甲酸对苯二酚酯,并对其结构进行了元素分析和ＩＲ测定,用差热分析仪和偏光显微镜对其液晶性进行了表征。     

几种热致性几列型液晶材料的合成与测试

以一定摩尔比的对烷氧基苯甲酰氯和对苯二酚钠，在常温常压下反应，合成了双对烷氧基苯甲酸对苯二酚酯，并对其结构进行了元素分析和ＩＲ测定，用差热分析仪和偏光显微镜对其液晶性进行了表征。     

新型催化剂Ru/NaY催化对苯二酚加氢

采用浸渍沉淀法制备了Ru/NaY、Ru/HY和Ru/C等钌催化剂,研究了其催化对苯二酚加氢制备1,4-环己二醇的活性。利用XRD和BET等手段对样品进行了表征。不同载体负载的催化剂上对苯二酚的转化率顺序为:Ru/NaYRu/HYRu/C。以Ru/NaY为催化剂,对苯二酚为原料,乙醇为溶剂,制备了1,4-环己二醇,对苯二酚的转化率99.8%。     

叔丁基对苯二酚的GC/MS分析

叔丁基对苯二酚(TBHQ)是一种油酯抗氧化剂,由对苯二酚与叔丁醇制得。本文采用气质联用(GC/MS)技术定性分析了其所含有的对苯二酚、2,5—二叔丁基对苯二酚、叔丁基对苯醌和2,5—二叔丁基对苯二醌等杂质;用气相色谱(GC)归一化法定量测定了叔丁基对苯二酚的含量。     

高岭土-Cu2O光催化降解对苯二酚的研究

采用水热法制备了高岭土-Cu_2O光催化剂,并且借助XRD、SEM等测试手段对其进行了表征。以对苯二酚为研究对象,考察了光源、催化剂用量、高岭土负载量、对苯二酚浓度等因素对光催化降解对苯二酚的影响。结果表明:以400 W金卤灯作为光源,在20 mL对苯二酚溶液中加入15%高岭土-Cu_2O 0.1 g,光照反应180 min后,可使初始浓度为5mg/L的对苯二酚降解率达到97%以上。     

DCC/DMAP法合成两种对称酯类液晶

本文通过1-溴己烷、1-溴辛烷分别与对羟基苯甲酸反应,其产物用DCC/DMAP高效酯化法与邻甲基对苯二酚合成的双-（对己氧基苯甲酸）邻甲基对苯二酚酯、双-（对辛氧基苯甲酸）邻甲基对苯二酚酯,通过红外、核磁、偏光显微镜等对其结构及液晶性能进行了研究。     

萜烯对苯二酚树脂的合成

研究了以无水三氯化铝为催化剂 ,松节油与对苯二酚聚合反应制备萜烯 对苯二酚树脂的情况。用IR、UV对产物进行表征 ,结果表明松节油与对苯二酚聚合得到了萜烯 对苯二酚树脂。探讨了聚合单体投料比、聚合时间、聚合反应温度和催化剂用量等因素对聚合反应的影响 ,得出了聚合反应的适宜条件。     

萜烯-对苯二酚树脂的合成

研究了以无水三氯化铝为催化剂 ,松节油与对苯二酚聚合反应制备萜烯 -对苯二酚树脂的情况。用IR、UV对产物进行表征 ,结果表明松节油能与对苯二酚共聚反应得到萜烯 -对苯二酚树脂 ,探讨了聚合单体投料比、聚合时间、聚合反应温度和催化剂用量等因素对聚合反应的影响 ,得出了聚合反应的适宜条件。     

热致性液晶聚氨酯的合成研究

合成了两种含聚酯液晶基元的液晶聚氨酯,研究了反应时间、不同原料对产物结构的影响,利用红外光谱（IR）、偏光显微镜（POM）、差示扫描量热分析仪（DSC）等手段确认其结构,正交偏光场观察证实,该液晶聚氨酯在一定温度范围内为热致性向列型液晶。     

Thermal and structural properties of tri-O-substituted cellulose ethers

Tri-O-substituted cellulose ethers prepared by the use of SO₂–diethylamine (DEA)–dimethylsulfoxide (DMSO) and powdered sodium hydroxide were characterized by measurement of melting points and degradation points and by differential scanning calorimetric (DSC) and X-ray analyses. Their thermal and structural characteristics were ascertained to be dependent on the kinds of substituents. Among the ethers examined, four kinds of arylmethylcelluloses showed the characteristics of thermotropic liquid crystals (smectic). Tri-O-α-naphthylmethyl-cellulose showed the three transformations due to a solid–smectic phase, a smectic–nematic phase, and a nematic–isotropic phase transformation. This thermotropic liquid crystal was enantiotropic below 200°C.     

热致液晶共聚酯60PHB/PEN的合成及其表征

合成了对乙酰氧基苯甲酸与聚萘二甲酸乙二醇酯的热致液晶共聚酯(简称60PHB/PEN)。通过元素分析、红外光谱、DSC、热台偏光显微镜以及广角X射线衍射对其进行了结构、液晶性表征。实验表明,合成的共聚酯确系高度无规的PEN、PHB共聚酯,在某个温度范围内呈现向列型液晶的典型特征。     

Thermotropic liquid crystalline copolyesters. I. Synthesis and thermal characterization of the copolyesters of terephthaloyl chloride,hydroquinone, and 1,4-butane diol

A new series of random thermotropic liquid crystalline polyesters (LCPs) was synthesized from terephthaloyl chloride, hydroquinone, and 1,4-butane diol. The copolyester composition was varied by changing the relative mole ratio of hydroquinone and 1, 4-butane diol in the feed. All the copolyesters displayed thermotropic liquid crystallinity at relatively low temperatures. Liquid crystalline behavior of the copolyesters has been characterized by polarizing light microscopy and by differential scanning calorimetry (DSC). The effect of co-polyester composition on the temperature and thermodynamic parameters related to liquid crystalline transition is discussed. © 1993 John Wiley & Sons, Inc.     

Photo-Orientation at the Interface between Thermotropic Nematic Liquid Crystal and Water Caused by Azobenzene Polymer Additives

Photoinduced orientational transitions in a thermotropic nematic liquid crystal caused by modulation of the boundary conditions at the water surface were observed and investigated. The initially degenerated planar anchoring of liquid crystal at the water surface becomes homeotropic under near-UV irradiation which induces photoizomerization of comb-shaped azobenzene polymer additives adsorbed from the liquid crystal to its interface with water. After irradiation, the photoinduced orientational structures spontaneously relax to the initial ones. It was shown that the orientational sensitivity to light irradiation strongly depends on the polymerization degree of azobenzene additives.     

Effect of Pyridine on the Mesophase of Teraryl Liquid Crystals: A New Series of Nematic Liquid Crystals Named 2-(4-Alkoxybiphen-4′-yl)-5-methylpyridines

A new series of teraryl 2-(4-alkoxybiphen-4′-yl)-5-methylpyridines (nO-PPPyMe, n = 3–8) nematic liquid crystal compounds, bearing a biphenylene core and a picoline terminus, were synthesized using a short two-step reaction, and overall yields between 34% and 38% were obtained. Spectral analysis results were in accordance with the expected structures. The thermotropic behavior of the teraryl liquid crystal compounds was investigated through polarized optical microscopy and differential scanning calorimetry. All compounds exhibited a solely enantiotropic nematic phase at the medium–high temperature range of 162.4–234.2 °C. Furthermore, the results for the nO-PPPyMe series were analyzed relative to three other compound series, mO-PPPyCN (m = 2–8), iO-PPQMe (i = 3–8) and xO-PPyPMe (x = 1–10). Consequently, the effect of pyridine on the mesophase of teraryl liquid crystals was demonstrated.     

The nature of crystallites in solidified,rigid-chain,liquid crystal polymers

Two rigid chain thermotropic liquid crystal polyesters have been examined by X-ray diffraction and thermal analysis in order to explore the nature of the crystallites in the solid state. A comparison of quenched and slow-cooled specimens indicates the presence in the quenched material of microcrystals that are too small to give clear X-ray lines. It is proposed that this is due to the very low surface energy associated with the nematic chain morphology. Both the enthalpy and entropy of fusion are much lower than in conventional polymers and are related to the molecular design of the thermotropic polymers.     

Liquid crystal polymer-carbon fiber composites. Molecular orientation

The objective of this work has been to study composite systems in which carbon fibers are dispersed in a liquid crystal polymer matrix. The fundamental point of interest here has been the interfacial response that fiber surfaces can potentially induce in self-ordering polymers. The matrix material used was a thermotropic liquid crystal polyester synthesized in our laboratory from the monomers p-acetoxybenzoic acid, diacetoxyhydroquinone, and pimelic acid. The aromatic-aliphatic polymer was characterized by NMR as a chemically disordered polymer of the three structural units which exhibits a nematic phase at temperatures above 150°C. Breadline proton NMR above the solid to liquid crystal transition was used to measure the rate of magnetic alignment of molecules in the matrix and polarized optical microscopy was used to analyze interfacial zones in composite samples. Fiber surfaces were found to influence the orientation and orientational dynamics of a liquid crystal polymer matrix. This was revealed by enhanced rates of magnetic orientation in the polymer melt when carbon fibers are dispersed in the medium. Fiber surfaces were also found to stabilize nematic ordering of the polymer as the melt was heated towards complete isotropization. The phenomena discovered here may originate in the development of zones around fibers with a common molecular orientation anchored by the carbon surface.     

Synthesis,Characterization and Texture Observations of Calamitic Liquid Crystalline Compounds

Several divinylic mesogenic monomers were synthesized based on coupling the monomer 4-(4-pentenyloxy)benzoic acid with chlorohydroquinone, 2,5-dihydroxy- acetophenone, methylhydroquinone or 2-methoxyhydroquinone. This resulted in novel mesogens of phenylene esters with different lateral substituent groups. The effect of the lateral substituent group on the thermotropic phase behavior for these liquid crystalline compounds was investigated using DSC and optical polarized microscopy. All the mesogens proved to have a wide nematic liquid crystalline range. Only the phenylene ester, which has a methoxy lateral substituent, exhibited both nematic and smectic phases. Structural confirmation of all new derivatives was accomplished by ¹H- and ¹³C-NMR spectroscopic analysis, along with CH elemental analysis.