液晶聚合物分子排列调控的研究进展

液晶的应用不仅仅局限于电视或电脑,具有光响应性的液晶在许多领域都存在应用,如平板显示、光学领域、光驱动设备以及许多正在发展的微科技领域. 液晶作为一种中间相的物质,既表现出了液体的流动性,又具有晶态的分子规整排列的性质. 液晶软物质材料具有许多有趣的性质,如自组装性质;长程有序的流动性;分子协同作用;双折射性质和物理性质（光、力、和电）的各向异性;外场诱导的表面分子取向;以及液晶弹性体的刺激响应性形变. 文中综述了具有不同液晶分子取向排列的液晶聚合物的刺激响应性形变,着重介绍了光取向技术诱导液晶分子取向的液晶聚合物的刺激响应性形变行为,并展望了未来液晶材料的设计在微流体和微型机器人领域的潜在应用.     

一种新型嵌段共聚物的物理性能

研究了由低相对分子质量聚砜链段与刚性棒状甸段组成的嵌段共聚物的物理性能。它们都具有液晶性，可溶解于氯仿－对氯苯酚混合溶剂，不溶于氯仿。且都有一个玻璃化转变温度和一个熔点，还对这些嵌段聚合物和刚性棒状液晶聚合物的性能进行了比较。     

含吸电子基的手性液晶聚合物合成和性能

设计与合成含胆甾醇基的液晶单体(4-烯丙氧基苯丙酸胆甾醇酯(M1)与含氰基的液晶单体(4-十一烯酰氧基联苯氰酯(M2)),并将其以一定比例投料与聚甲基含氢硅氧烷(PMHS)接枝共聚,合成了一系列含吸电子基的手性侧链液晶聚合物.通过热分析、偏光显微分析、旋光仪等测试手段研究了单体M1,M2和手性液晶聚合物液晶性能.结果表...     

Effect of crystallization temperature and propylene sequence length on the crystalline structure of propylene-ethylene random copolymers

Crystallization behavior and resultant crystalline structure of a series of temperature-rising elution-fractionated specimen of a Ziegler-Natta catalyst-synthesized propylene-ethylene random copolymer were studied by DSC, WAXD and AFM. The experimental results indicate that both crystallization temperature and propylene sequence length exhibit great influence on the crystallization behavior and crystalline structure of the copolymer. It was found that the ethylene co-monomers acting as point defects inserted into the polypropylene chains play an important role in the formation of y-iPP. As the co-monomer content increases, the crystallizable sequence length of iPP decreases, which produces an appropriate condition for its y crystallization. At the same time, the existence of chain defects leads to a lower crystallinity of the copolymer and imperfection of the resultant crystals. For each individual sample with certain propylene sequence length or ethylene content, the increment of y-iPP crystal content with increasing crystallization temperature demonstrates that higher crystallization temperature is in favor of the y-iPP crystallization. Pure y-iPP crystals have been got in samples with propylene sequence length lower than 21 under suitable crystallization conditions.     

高分子液晶毛细管色谱柱的制备及性能评价

合成了三种聚硅氧烷侧链型高分子液晶，用静态法将它们分别涂渍在经预处理的玻璃毛细管柱上，制成高分子液晶气相色谱柱。测定了色谱柱的柱效及其随载气流速、测试柱温的变化，以及对多环芳烃同分异构体的分离选择性。测试结果表明，其中两种色谱柱具有良好的分离性能。     

耐高温高分子材料的热分解动力学

本文用热重法研究了四种耐高温分子材料:聚芳醚酮酮、热致性液晶共聚芳酯、溶致性液晶聚芳酰胺和聚间苯二甲酰间苯二胺的热分解动力学.采用Ozawa方法和Coata-Redforn方法处理并计算了热分解动力学参数:活化能Ed、反应级数n、频率因子A．     

含两种介晶基元的侧链聚硅氧烷的液晶性能

用两种液晶单体 4 丙烯酰氧基 1 丁酸胆甾醇酯和 4 烯丙氧基苯甲酸对氰基苯酯通过接枝共聚 ,引入到聚甲基含氢硅氧烷中制得了一系列侧链液晶聚合物·通过采用傅立叶转换红外光谱 (FTIR)对其结构进行了表征·用差示扫描量热方法 (DSC)及偏光显微分析方法 (POM )等研究了该系列液晶聚合物和单体的液晶性能·随着聚合物结构中胆甾醇酯类单体组分质量分数的增加 ,系列液晶聚合物的玻璃化温度呈现上升趋势·所有聚合物都具有较宽的介晶相范围·     

Observation of shear-induced nematic-isotropic transition in side-chain liquid crystal polymers

Flow-induced phase transitions are a fundamental (but poorly understood) property of non-equilibrium systems, and are also of practical importance for tuning the processing conditions for plastics, petroleum products, and other related materials. Recognition that polymers may exhibit liquid crystal properties has led to the discovery of the first tailored side-chain liquid crystal polymers (SCLCPs), which are formed by inserting a spacer between the main polymer chain and the lateral mesogen liquid-crystalline graftings. Subsequent research has sought to understand the nature of the coupling between the main polymer chain and the mesogens, with a view to obtaining better control of the properties of these tailored structures. We show here that the parallel or perpendicular orientation of the mesogens with respect to the main chain can be reversed by the application of an external field produced by a shear flow, demonstrating the existence of an isotropic nematic phase transition in SCLCPs. Such a transition, which was theoretically predicted for low-molecular-weight liquid crystals but never observed, is shown to be a general property of SCLCPs too. We expect that these SCLCPs will prove to be good candidate systems for the experimental study of these non-equilibrium phenomena.     

Simulation investigations in the binding energy and mechanical properties of HMX-based polymer-bonded explosives

The molecular simulations of the well-known high explosive [β-HMX (cyclotetramethylene tetranitramine) and its fluorine containing polymer-bonded explosives (PBXs) were carried out with the combination method of quantum mechanics, molecular mechanics and molecular dynamics. The atomic cluster model, containing the [β-HMX molecule and the polymer molecule whose chain dimension was about the same as β-HMX‘s, was fully optimized by AM1 and PM3 semi-empirical molecular orbital and molecular mechanical methods using COMPASS and PCFF force field. Then the calculated binding energy is found to be linearly correlated to each other. Molecular dynamics simulations using COMPASS force field were performed for [~-HMX crystal and the PBXs involving [β-HMX and a series of fluorine containing polymers. Their elastic coefficients, moduli and Poisson‘s ratios were calculated. It is found that the mechanical properties of β-HMX can be effectively improved by blending with fluorine containing polymers in small amounts.     

含β-环糊精液晶聚合物的合成与性能

将修饰的β-环糊精衍生物单-(6-丙烯酰乙二氨基-6-去氧)-β-环糊精二十乙酸酯(M1)作为手性单体,4-十一烯酰氧基苯甲酰氧基-4’-乙氧基苯甲酰氧基对联苯酚双酯(M2)作为液晶单体,与聚甲基含氢硅氧烷接枝共聚,得到含β-环糊精基元的液晶聚合物P1～P7.通过FT-IR,1H NMR,DSC,POM,TGA,XRD,旋光分析等手段对所获单体及聚合物的结构、相行为等性能进行了表征与测试.结果表明,单体M1为非液晶手性单体,其比旋光度为+95.30,单体M2呈现向列相的丝状织构,聚合物P1～P7均有液晶性,它们的热稳定性良好,热失重5%时的温度均在300℃左右,随着手性单体M1含量的增加,聚合物的液晶区间变窄,比旋光度值增加.     

侧链型液晶聚合物接枝碳纳米管的制备及性能研究

合成了一种侧链型液晶单体4-(4’-烯丙氧基)苯甲酰氧基联苯单酯,将不同含量的CNT接枝到侧链液晶单体上,然后液晶单体发生聚合反应生成液晶复合材料.采用偏光显微镜(POM)、扫描电子显微镜(SEM)、差示扫描量热仪(DSC)等考察了碳纳米管的分散排列情况以及复合材料的热性能,测试结果显示,少量的碳纳米管能够较好地分散在复合材料基体中;DSC结果显示,CNT的引入提高了复合材料的清亮点,增加了液晶区间.     

含磺酸离子的侧链液晶聚硅氧烷的合成与表征

液晶单体M1(4-烯丙氧基苯甲酰氧基-4′-甲氧基苯甲酰氧基联苯),M2(4-烯丙氧基苯甲酰氧基-4′-丁基苯甲酰氧基苯)和离子单体M3(4-烯丙氧基偶氮苯磺酸)与含氢聚硅氧烷进行共聚合反应,制备了含磺酸离子的侧链液晶聚硅氧烷·其结构和液晶性能通过红外光谱(IR),差示扫描量热法(DSC)、偏光显微分析法(POM)、热重分析法(TG)进行了表征·研究结果表明,离子基团的引入,降低了液晶性能,但是没有改变其液晶类型·     

甲亚胺液晶共聚醚的合成及研究（Ⅲ）

利用介晶基和非个晶基共聚的方法合成高分子液晶，详尽介绍了合成方法和对产品的测试表征，并介绍了所合成的聚合物要呈现液晶态，允许非介晶组分在其组成中所占的最高含量。     

氢键型液晶高分子的研究进展

氢键型液晶高分子是由经化学修饰过的高分子通过氢键形成的高分子复合物,具有独特的动力学功能,分子结构调整和修饰简便,可用于显示器、光电元件、信息传导等研究领域,具有极好的应用前景。着重介绍了主链型、侧链型、组合型以及网络状等类型的氢键型液晶高分子的研究现状及其进展。     

热致型高分子的液晶度与结晶度

利用解偏振光强(DLI)、广角X-射线衍射(WAXD)及密度测定等方法,对目前国内外尚有争议的聚合物液晶态相态系统进行了研究,就聚合物液晶相的均相异相问题提出了新的看法,认为聚合物液晶相仍是一个异相系统,但由于聚合物处于液晶态时,分子排列比较规整,加之其特殊的粘度特性,致使液晶体系中液晶的不完善程度较结晶的不完善程度小,也即液晶度高于结晶度,从而解释了聚合物由结晶态进入液晶态时解偏振光强突然增大的反常行为。     

甲亚胺液晶共聚醚的合成及研究（Ⅳ）

用个晶基和柔性更好的非个晶基共聚的方法合成高分子液晶，通过热台偏光显微镜、ＤＳＣ和Ｘ－光衍射仪对所合成的共聚物进行了结构和相态表征，讨论了共聚物组成对共聚物相变温度和相态的影响，确定了共聚物要呈现液晶态，允许非介晶组份在其组成中的最高含量。     

含葡萄糖基元的胆甾型液晶聚合物的合成与表征

把手性单体1-O-(十一烯)-β-D-四乙酰葡萄糖苷(M1)和液晶单体4-烯丙氧基苯甲酸胆甾醇酯(M2)接枝到聚甲基含氢硅氧烷上,手性单体的摩尔分数从0至30%,得到系列液晶聚合物.通过红外光谱(IR)、核磁共振谱(1HNMR)、旋光分析、差示扫描量热法(DSC)、偏光显微分析法(POM)、热失重分析法(TGA)、X射线分析等手段研究了手性单体对侧链胆甾型液晶聚合物性能的影响.结果表明P1~P7都有液晶性且为胆甾型液晶聚合物,系列液晶聚合物的tg和ti随手性单体含量的增加而降低,P1~P7具有较宽的液晶相范围,热稳定性较高,质量损失5%时的热失重温度均在300℃左右.     

Synthesis and characterization of sidechain liquid cryastalline polysiloxanes containting either cholesteryl or cyanobiphenyl mesogenic groups

A series of side-chain liquid crystalline polysiloxanes containing either cholesteryl or cyanobiphenyl mesogenic groups were synthesized by the hydrosilylation reaction of a polysiloxane containing Si−H group with a vinyl-terminated compound containing the mesogenic group. Their chemical structures were confirmed by IR,¹H NMR, and elemental analysis, Their phase behaviors were investigated by differential scanning calorimetry, optical polarizing microscope, and X-ray diffraction technique. The results show that all these polysiloxanes except P V display smectic or nematic mesonorphism or both. The dependence of phase transition temperature on the rigidity of mesogenic unit. the length of spacer group, and the flexibility of chain is also described. Supported by the National Natural Science Foundation of China Xu Guangwei: born in June 5, 1970, Postgraduate     

制膜参数对含有高分子液晶超滤膜结构的影响

研究了高分子液晶浓度、添加剂含量、蒸发温度和蒸发时间四种制膜参数对含有高分子液晶的聚砜超滤膜结构的影响.结果表明,除添加剂含量外,其他制膜参数都是通过改变初生态膜(液态膜)表层聚合物浓度影响膜表层孔径及孔隙率.在一定范围内,高分子液晶浓度增加,膜表层孔径减小、孔隙率增加,超过此范围则结果相反.添加剂浓度的增大,使膜的孔隙率升高,而且使膜内部指状孔长度增加、连通性增强     

Micro- and nano-structured conducting polymeric materials

Conducting polymeric materials with micro-/nano-structures have potential applications in fabrication of various optical, electronic, sensing and electrochemical devices. This Is mainly because these materials not only possess the characteristics of conducting polymers, but also have special functions based on their micro-or nano-structures. In this review, we summarize the recent work on “soft” and conducting polymers and open up the prospects of the main trends in this field.