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1.
超分子聚合物与传统的聚合物在制备方法、结构和性能上都有很大不同。近年来,超分子科学的研究应用工作飞速发展。本文通过对超分子液晶、金属-超分子聚合物、自组装超分子膜的介绍,介绍了超分子聚合物的研究应用进展。  相似文献   

2.
《工程塑料应用》2007,35(7):88-89
一种含超分子液晶结构的PA液晶与PA共混物的制备方法,属于PA共混物液晶化自增强工程塑料领域。由于刚性分子与柔性分子聚合物的结构差异较大,二者很难形成分子级别相容的共混物。本发明首先合成PA液晶,然后利用溶液共混的方法,通过PA液晶和PA之间强烈的分子间氢键作用,将物质的量比为1:1的PA液晶与PA自组装合成了具有超分子液晶的共混物。  相似文献   

3.
氢键的温度敏感性和可逆性对聚合物热力学性质、微观自组装、结晶及液晶行为有重要影响,因而在超分子聚合物的设计与结构控制方面受到广泛关注。详细介绍了氢键型超分子聚合物的研究现状及其进展。  相似文献   

4.
氢键具有方向性、较强的结合力、动态可逆性以及可预测的识别性能等优点,在超分子聚合物的构筑与性能改善方面有着广泛的应用。本文根据氢键结合位点的数目,系统地综述了主链型、侧链型和结合型氢键超分子聚合物的研究进展;重点阐述了各类氢键结合单元的设计及其在改善聚合物性能中的作用;同时介绍了氢键结合单元在纳米材料、凝胶、液晶等众多领域的应用。在此基础上,展望了未来氢键型超分子聚合物的研究方向,主要包括设计合成能够在生理条件下稳定的多重氢键结合单元以及深化组装机理的研究。  相似文献   

5.
棒状线圈三嵌段共聚物的液晶超分子结构研究进展   总被引:1,自引:1,他引:0  
如何获得能形成纳米尺寸的新型超分子材料以及研究这些结构对材料性质的影响成为当今分子设计的热点。由刚性芳香核(棒状Rod:B)及柔性链(线圈状Coil:A或C)组成的棒状线圈三嵌段共聚物能在纳米尺度上自组装出丰富多彩的纳米液晶超分子结构。介绍了不对称ABC(Coil-Rod-Coil)、对称ABA(Coil-Rod-Coil)及BAB(Rod-Coil-Rod)棒状线圈三嵌段共聚物的液晶超分子行为,讨论了疏水性作用力、各嵌段体积大小、分子形状、分子长度等结构因素的改变对这类三嵌段共聚物液晶分子自组装结构的影响,介绍了棒状线圈三嵌段共聚物组装形成的一序列一维层列相、二维柱相及三维的立方、四方相等多种连续的及不连续的复杂纳米液晶超分子结构。  相似文献   

6.
超分子聚集和纳米分离是设计和制备新型液晶功能材料的有效工具。利用氢键相互作用实现分子组装构筑超分子液晶体系已成为近年来最活跃的研究领域。具有较强电子亲和力的三嗪单元作为典型的电子受体可以作为形成氢键的理想基团。本文综述了在氢键作用下三嗪类化合物及其复合物的液晶行为研究进展。  相似文献   

7.
本文从主客体之间结合方式的角度总结了超分子聚合物的种类及其制备,包括基于氢键结合、基于π-π结合、基于双亲性分子自组装以及基于配位键,静电作用的超分子聚合物等类型,并对超分子聚合物的研究进展进行了展望。  相似文献   

8.
有序孔结构功能与应用广泛,但长期以来对有序孔结构研究局限于固态。总结了水溶性的有序自组装孔结构-超分子有机框架(Supramolecular Organic Frameworks,SOFs)的研究进展,内容包括相关超分子化学和分子自组装研究的发展背景、有孔超分子聚合物的构建及有序性控制研究背景、不同拓扑结构的超分子有机框架的组装及其催化和药物输送功能探索(主要通过疏水作用驱动的葫芦脲[8]对两个同体或异体芳香二聚体的包结作用。展望了水溶性有序超分子孔结构的研究前景。  相似文献   

9.
综述了近十年来国内外报道的分子间自组装盘状液晶的研究进展;重点阐述了通过分子间氢键或金属离子配位键自组装的盘状液晶小分子和超分子液晶的液晶性能、掺杂了无机纳米粒子的通过氢键形成的液晶材料的光电性能及其在有机光伏器件中的应用;最后总结了不同类分子间自组装盘状液晶的性能优势。综合文献报道可知,引入分子间氢键或配位键可以更好地实现盘状液晶在特定功能材料中的应用,并且自组装的盘状液晶还可与纳米粒子形成复合物,得到具有特定功能的纳米复合材料。  相似文献   

10.
分子自组装技术的研究现状   总被引:1,自引:0,他引:1  
综述了分子自组装技术目前的研究进展,并对接枝、旋涂、化学吸附、分子沉积、慢蒸发溶剂等成膜方法作以介绍,简介了分子自组装技术在液晶、非线性光学材料、聚合物表面改性等材料领域的应用,并对其今后的发展作出预测。  相似文献   

11.
BACKGROUND: Owing to the unusual structural rearrangement of polychloromethylthiirane (PCMT) at room temperature, it has not been used as the main‐chain backbone of side‐chain liquid‐crystalline polymers (SLCPs). However, it has been observed that PCMT has a relatively stable and clear structure under special conditions. Therefore, we attempted to synthesize SLCPs using PCMT as main‐chain backbone and investigated their thermal behavior. RESULTS: New polymers, poly[1‐({(4‐methoxyazobenzene‐4′‐oxy)alkyl}thio)‐2,3‐epithiopropane], in which the number of methylene units in the alkyl group is 4, 5 or 6, were prepared by means of reactions of corresponding (4‐methoxyazobenzene‐4′‐oxy)alkylthiols with PCMT. The structures of these compounds were confirmed using elemental analysis and 1H NMR spectroscopy. The substitution ratios of the copolymers with 4, 5 and 6 methylene units in the alkyl group were 56, 75 and 80%, respectively. Differential scanning calorimetry measurements and polarized optical microscopy observations showed that the resulting copolymers exhibited thermotropic liquid‐crystalline mesomorphism with nematic phase except for the copolymer with a 56% substitution ratio. The decomposition temperature of all the synthesized copolymers was near 195 °C. CONCLUSION: This investigation has demonstrated that PCMT polymerized for 8 h has the ability to act as a suitable main‐chain backbone for SLCPs. Moreover, SLCPs could be obtained only by the reaction of PCMT with thiolate salt containing mesogenic groups. The substitution ratios increased with increasing number of methylene groups in the spacer. Copyright © 2009 Society of Chemical Industry  相似文献   

12.
Huntington’s disease (HD) is a genetic neurodegenerative disorder characterized by motor, cognitive, and psychiatric symptoms, accompanied by massive neuronal degeneration in the striatum. In this study, we utilized solid lipid curcumin particles (SLCPs) and solid lipid particles (SLPs) to test their efficacy in reducing deficits in YAC128 HD mice. Eleven-month-old YAC128 male and female mice were treated orally with SLCPs (100 mg/kg) or equivalent volumes of SLPs or vehicle (phosphate-buffered saline) every other day for eight weeks. Learning and memory performance was assessed using an active-avoidance task on week eight. The mice were euthanized, and their brains were processed using Golgi-Cox staining to study the morphology of medium spiny neurons (MSNs) and Western blots to quantify amounts of DARPP-32, brain-derived neurotrophic factor (BDNF), TrkB, synaptophysin, and PSD-95. We found that both SLCPs and SLPs improved learning and memory in HD mice, as measured by the active avoidance task. We also found that SLCP and SLP treatments preserved MSNs arborization and spinal density and modulated synaptic proteins. Our study shows that SLCPs, as well as the lipid particles, can have therapeutic effects in old YAC128 HD mice in terms of recovering from HD brain pathology and cognitive deficits.  相似文献   

13.
探究了以磷酸分解磷矿,关键酸解工艺参数对磷及Fe、Al、Mg、Pb、As浸出的影响规律,并从热力学角度进行了分析。结果表明,磷矿内磷及Fe、Al、Mg浸出率随磷酸质量分数、反应温度、反应时间和液固比的增大而增大,搅拌速度影响不明显;Pb浸出率随磷酸质量分数、反应温度和液固比的增大而增大,搅拌速度、反应时间影响不明显;As浸出率随反应温度升高呈先增大后减小趋势,随反应时间增加略有减小,磷酸质量分数、搅拌速度和液固比影响不明显。控制磷酸质量分数为30%(以P2O5计)、反应温度为80 ℃、搅拌速度为300 r/min、反应时间为150 min、液固质量比为10∶1,在此条件下,磷及Fe、Al、Mg、Pb、As的浸出率分别为98.65%、68.56%、48.54%、95.84%、32.85%和84.62%。通过热力学分析表明磷矿内Mg、As浸出率较高,Pb浸出率较低,而Fe、Al浸出率大小主要取决于磷矿中褐铁矿及高岭土含量。  相似文献   

14.
Conclusions The most common and characteristic forms of scrap of magnesia parts differing in form, dimensions, and composition are shown. These include deviations of the dimensions from the nominal, breaking off of the corners and edges, nonuniformity, welding together, spots, voids, fire cracks, spalls, and cracks of different origin.The reasons for formation of scrap were determined. The primary of them are the reduced quality of the raw material (chromite, magnesite) with a larger quantity of impurities containing limited silicon and calcium oxides, sometimes insufficient density, grain size, and completeness of hydration of the magnesite powders, nonconformity of the bunker, proportioning, mixing, and pressing equipment to the requirements of modern production of progressive high-quality refractories, the insufficiently high binding capacity of lignosulfonates, deviations in the quality of assembly and finishing of press equipment and automatic ejectors, of the car floor lining, and in firing conditions, a high variation in density of the green parts, and nonuniform heating and cooling in the volume of the parts and of the whole charge during firing. More than 50% of the total scrap of all forms is due to firing scrap of parts.The primary means of reducing or eliminating scrap of parts and simultaneously increasing their quality based on the reasons for formation of different forms of it were noted. These above all else, are increasing the volumes and improving and introduction of new methods of concentration of magnesite and chromite, a successive increase in the share of chrome concentrates, chromium-containing broken parts, and powders by firing of magnesite and caustic dust in the production of magnesia refractory parts as the result of a decrease in the share of commercial natural chromite and magnesite, the use in the production of parts of high-quality type PMSP-93 powder produced in shaft kilns and used as the charge for production of fused materials, the use of the prospect of processes for production of dense periclase powders uniform in chemical analysis from recovered caustic dust, replacement of obsolete mixing and press equipment by more modern, increasing the strength of green parts by above all else improving the binding properties of LST and increasing pressing pressure, forming of the taper of parts by the side plates of the die, improving the quality of assembly and increasing the reliability of functioning of press equipment and automatic ejectors, improving car floor linings, introduction of new methods and increasing the volumes of production of progressive unfired refractories in place of certain forms of fired parts, observation of all production parameters, and a relationship of the wages of labor to the quantity of scrap and the quality of refractories.Introduction of the new management system and the active work of the quality groups created will open up and lead to the action of unutilized reserves for reduction of scrap.Translated from Ogneupory, No. 2, pp. 31–38, February, 1989.  相似文献   

15.
20世纪90年代以来,随着计算机技术和测量仪器的迅速发展,化学工程的研究水平日益提升,由经验规则的判断逐渐提高到计算机模拟量化分析. 化学工程的研究范围也日益扩大,下至纳微尺度结构与界面的观察与量化,上至宏观尺度设备与工厂的系统集成. 化学工程的服务对象也由化学工业扩展到冶金、材料、能源、环境、生物等诸多进行物质转化的过程工业. 目前化工科技界正在呼吁寻求继第一里程单元操作、第二里程传递过程和化学反应工程之后的第三里程. 化学工程中以往惯用的忽视非均匀多尺度结构和界面存在的平均方法是造成预测偏差和调控、放大困难的主要原因. 必须关注结构、界面和多尺度问题,研究多尺度结构、界面的量化预测理论和优化调控方法,建立多尺度结构、界面与"三传一反"的关系模型,与当代先进的计算方法、计算流体力学和计算机模拟相结合,有望解决化工过程与设备的优化调控与放大的难题,成为化学工程发展的新里程.  相似文献   

16.
以聚乙烯吡咯烷酮(PVP)为分散剂,乙醇和水为反应介质,偶氮二异丁腈为引发剂,甲基丙烯酸甲酯(MMA)为单体,采用分散聚合工艺,制备了单分散微米级PMMA微球。研究了乙醇/水介质的配比、反应温度、分散剂用量、单体用量、引发剂用量对PMMA微球粒径和粒径分布的影响。结果表明,PMMA微球粒径随乙醇用量的增加先增大后减小;随反应温度的升高先增大后减小,粒径分布先变窄再变宽;随单体用量的增加先增大后减小,随引发剂用量的增加而增大;随PVP用量的增加而减小,粒径分布先变窄再变宽。  相似文献   

17.
张军  贾悦  刘博  张则俊  安静  蔡贤明 《化工进展》2020,39(z2):372-378
集输过程中的含油污泥具有成分复杂、含液率高、乳化胶结稳定等特性,占油田危险废物新增量的约60%,是污染防治的重点。近年来,学者们开展了大量“调质-固液分离”减量化技术降低其环境风险和处置成本,但仍存在需要针对含油污泥不同来源优选相匹配的减量化调质方法和装置的难题。为此,本文回顾了氧化、破乳、絮凝、干化/半干、超声波、微波等化学与物理调质方法,离心机、叠螺机、压滤机3种固液分离装置研究进展,通过分别对各种调质方法及装置的对比分析,重点阐述了其作用机理、优缺点、适用对象。其中化学调质方法中破乳氧化、加酸更适用于高含聚油泥;表面活性剂破乳需加热,可与超声波相结合;有机和无机絮凝剂配合可提高罐底泥中油回收效果;干化/半干化法受经济效益制约。在文献基础上,认为未来应加强生物表面活性剂、生物电化学系统、椭圆叠螺机、基于固液分离装置数值模型基础上的设计与优化软件、多学科相结合的减量化耦合技术研究。  相似文献   

18.
Interrelationships Between Skin, Vehicle and Drug During Penetration into Human Skin II: Vehicle and Penetration Interrelationships between skin fat and vehicle, skin fat content and uptake of vehicle fat, as well as between surface fat and penetration of the substance are discussed. Furthermore, penetration of components of the vehicle, consistency of the vehicle and liberation of substances, physicochemical properties of substances, the influence of polarity and partition coefficient on the process of penetration, solubility and distribution in the vehicle phases and in the corneous layer of the skin, as well as the kinetic (dependent on the vehicle) of a substance in the corneous layer, epidermis, and cutis are explained. Conclusions of practical significance are drawn, which enable to choose an optimum vehicle for a definite substance and determine the frequency of application.  相似文献   

19.
20.
中国盐湖资源开发利用现状与发展建议   总被引:1,自引:0,他引:1       下载免费PDF全文
中国现代盐湖发育,卤水中无机盐资源丰富,除蕴含钾、钠、氯、镁等元素外,锂、硼、铷、铯、碘、溴等总体储量也颇为可观,开发与应用前景极为广阔。高效开发与综合利用盐湖资源是矿业公司降低成本、提升效益、优化结构、转型升级和增强企业核心竞争力的必然选择与重要途径。概述了中国盐湖资源特点、论述了盐湖资源综合利用研究与开发利用现状,指出国内盐湖产业开发利用进程中面临的主要问题,进而为维护国家粮食安全、能源资源与新材料安全、保障全国盐湖资源的可持续发展提出加强资源利用管理、提高资源利用效率、加大战略资源储备、强化生产要素保障、构建领先产业体系和推动产业跨界合作等相应的对策建议。  相似文献   

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