聚离子液体功能材料研究进展

聚离子液体(PILs)材料兼具离子液体和聚合物的性质, 近年来已经在高分子化学、材料科学及能源科学等领域得到初步应用, 并引起了人们广泛关注. 本论文介绍了聚离子液体的合成, 综述其在(准)固态电解质、燃料电池聚电解质膜、刺激响应性功能材料, 以及碳材料等相关领域的研究与应用.     

~1H-NMR谱表征聚异戊二烯和聚间戊二烯及异戊二烯间戊二烯共聚物的微观结构

利用400 MHz高分辨率核磁共振氢谱,首先对聚异戊二烯橡胶和聚间戊二烯橡胶的微观结构分别进行分析,进而对异戊二烯-间戊二烯共聚物的微观结构进行了研究,建立了聚异戊二烯、聚间戊二烯以及异戊二烯间戊二烯共聚物微观结构的核磁共振氢谱分析方法。     

近年来锂有机化合物的研究和应用

前言近年来,锂有机化合物的研究工作发展非常迅速,应用相当广泛。这主要是由于它在精细有机、基本有机、高分子合成的理论和实际应用方面起着许多重要而独特的作用。例如,锂有机化合物能使异戊二烯聚合得到含94%顺-1,4-聚异戊二烯橡胶;又如,用苯基锂和三氯三苯基硼氮六     

功能化聚离子液体的设计合成及应用研究

聚离子液体(Poly(ionic liquid)s)是指由离子液体单体聚合生成的,在重复单元上具有阴、阳离子基团的一类离子聚合物。功能化聚离子液体是由功能化离子液体发展而来,兼具离子液体和高分子聚合物的性质。该类研究着眼于结构可控性质,设计合成具有特殊性能的、稳定的、功能化材料。近年来已经在高分子化学、电化学、材料科学及能源科学等领域得到初步应用。本论文综述聚离子液体在固态电解质和聚电解质膜、智能响应性功能材料,以及聚离子液体基碳材料、聚离子液体/碳纳米杂化材料、催化等相关领域的研究与应用。     

硫化反式聚异戊二烯电子性质的理论化学研究

应用量子化学计算方法,对反式聚异戊二烯本征态和硫化态结构的能量及电子性质等进行了计算.结果表明,当聚异戊二烯掺杂硫后,相邻两链之间的距离a⊥变窄,体系的总能量降低,从而使整个掺杂体系更加稳定.另外,在硫化聚异戊二烯分子中,S原子位于两个相邻聚异戊二烯链之间,并偏向于其中一个分子链的C C双键的一侧,即与相邻两链中相对应的两个C C双键形成π-p-π共轭体系,增加了电子在两个聚异戊二烯链间的流动性,从而使硫化的反式聚异戊二烯更加稳定.另外,根据固体能带理论,采用量子化学EHMO方法,对反式聚异戊二烯本征态和硫掺杂态的能带结构进行了计算,根据硫化前后能隙和带宽的变化,解释了反式聚异戊二烯掺杂后呈现电导率各向异性的原因.     

橡胶弹性模型的新进展

传统橡胶弹性模型存在一定的局限性,例如不能真实地反映橡胶的交联网络结构,不能解释多个网络结构参数对橡胶力学性能的影响,也不能很好地描述大变形条件下橡胶的弹性.为了解决上述科学问题,崔树勋等提出了一个新的模型(TCQMG模型),在该模型中橡胶交联网络同时包含顺-1,4-聚异戊二烯和聚硫,并且高分子链的弹性同时包含了熵弹性和焓弹性.研究表明,新的模型不仅可以很好地描述硫化橡胶的弹性,还可以解释硫含量等参数对橡胶性能的影响.考虑到天然橡胶与其他橡胶甚至超分子水凝胶在网络结构上的相似性,新模型也可能用于描述这些材料的力学性能.     

环化顺1,4丁二烯异戊二烯无规共聚物的表征

<正> 已知,聚异戊二烯或聚丁二烯等1,3-双烯聚合物可在路易斯酸催化剂作用下按阳离子型机理进行分子内环化反应,所得“环化橡胶”,做为可光敏固化的新材料,在光刻胶、光保护膜、胶粘剂等方面得到广泛应用。文献还表明,环化顺1,4聚双烯产物比环化其它结构的聚双烯产物具更好的使用性能。鉴于合成高分子材料中共聚物往往较均聚物呈现     

镍催化杂芳烃的非天然戊烯基化及环状单萜化反应（英文）

萜类化合物,如半萜类和单萜类,是天然产物中种类最繁多、结构最多样的一类,广泛存在于植物和海洋生物中,在人类的日常生活中具有重要的应用价值.自然界中,二甲基烯丙基焦磷酸酯(DMAPP)和异戊烯基焦磷酸酯(IPP)在各种酶的作用下经过偶联、重排、环化以及异构化等反应合成萜类化合物.传统的人工方法大多依赖于过渡金属催化的异戊烯基以及反异戊烯基前体的反应,该反应不仅需要当量的金属试剂,且反应过程中也会产生当量的副产物,不符合绿色环保以及原子经济性原则.异戊二烯作为一种廉价易得的大宗化学品,其高附加值转化一直是学术界和工业界关注的焦点.但由于异戊二烯具有反应活性低以及区域选择性调控难的特点,氢芳基化产物最多可达到十四种异构体.此外,异戊二烯容易发生二聚、三聚以及调聚等反应,产生复杂产物.上述问题使得异戊二烯的高附加值转化具有很大挑战性.在前期关于异戊二烯氢官能团化以及手性二聚研究的基础上,本文提出了一种以异戊二烯为原料,通过接力催化策略,在杂芳环中引入非天然戊烯基和环状单萜骨架的方法.具体而言,使用廉价金属镍作为催化剂,小位阻的氮杂环卡宾作为配体,在当量碱的条件下,通过马氏加成得到异戊二烯4,3...     

聚碳酸酯基固态聚合物电解质的研究进展

液态锂离子电池由于采用易泄露、易挥发、易燃烧的碳酸酯有机溶剂,在高温或极端条件下使用时,存在极大的安全隐患.使用固态电解质替代液态电解液,可以从根本上避免此类安全问题的发生,与此同时还可以大幅度提升固态锂电池的能量密度.固态电解质又分为无机固态电解质和聚合物固态电解质2大类.无机固态电解质能够在宽的温度范围内保持化学稳定性,并且电化学窗口较宽,机械强度更高,室温离子电导率较高,但脆性较大,柔韧性差,制备工艺复杂,成本较高.聚合物固态电解质,室温离子电导率偏低,难以满足室温锂离子电池的应用,但其加工成型容易,形状可变.比较而言,固态聚合物电解质,更适宜大规模生产,离产业化相对更近.固态聚合物电解质中研究较多的是聚醚基固态聚合物电解质(如聚环氧乙烷和聚环氧丙烷),但其缺点是室温离子电导率低,需要对其改性或进一步开发综合性能更加优异的其他固态聚合物电解质.聚碳酸酯基固态聚合物电解质由于其特殊的分子结构(含有强极性碳酸酯基团)以及高介电常数,可以有效减弱阴阳离子间的相互作用,提高载流子数量,从而提高离子电导率,因此被认为是一类非常有前途的固态聚合物电解质体系.基于此,本文重点综述了最近研究热点的聚碳酸酯基固态聚合物电解质,包括聚(三亚甲基碳酸酯)体系、聚(碳酸丙烯酯)体系、聚(碳酸乙烯酯)体系和聚(碳酸亚乙烯酯)体系等,并详细阐述了上述每种聚碳酸酯基固态聚合物电解质的制备、电化学性能、优缺点及改性手段,归纳出其离子配位-解配位过程和离子扩散机制,还对聚碳酸酯基固态聚合物电解质的未来发展方向和研究趋势望进行了预测和展望.     

多硫化物的液体聚合物

由聚硫橡胶化学协会N.J.Trenton所制成的多硫化物的液体聚合物(Liquid Polysulfide polymer以下简称液体聚硫橡胶)是一种由二氯二乙基缩甲醛(Dichlordithylformal亦可译作二氯烷烴类)和多硫化钠作用而得的低分子聚合物。它们便是人们久已熟知的以二氯乙烷和     

含偶氮基团的聚丙烯酸酯型功能侧链液晶高分子的性能及其应用前景

综述了基于具光致双折射和光存储性质的偶氮功能基团的新型功能性侧链液晶聚丙烯酸酯的液晶性质、光电性质及应用前景.指出该类聚合物是一类非常重要的非线性光学材料 ,一般显示热致性向列型或近晶型液晶相, 液晶相转变温度和液晶态温度范围随链结构的不同发生显著变化,具有较短的电场及光场响应时间.此类材料在不断开发研究下可望用作长久的高对比度的光学信息储存材料.     

Recent advances and trends in miniaturized sample preparation techniques

Advances in the area of sample preparation are significant and have been growing significantly in recent years. This initial step of the analysis is essential and must be carried out properly, consisting of a complicated procedure with multiple stages. Consequently, it corresponds to a potential source of errors and will determine, at the end of the process, either a satisfactory result or a fail. One of the advances in this field includes the miniaturization of extraction techniques based on the conventional sample preparation procedures such as liquid‐liquid extraction and solid‐phase extraction. These modern techniques have gained prominence in the face of traditional methods since they minimize the consumption of organic solvents and the sample volume. As another feature, it is possible to reuse the sorbents, and its coupling to chromatographic systems might be automated. The review will emphasize the main techniques based on liquid‐phase microextraction, as well as those based upon the use of sorbents. The first group includes currently popular techniques such as single drop microextraction, hollow fiber liquid‐phase microextraction, and dispersive liquid‐liquid microextraction. In the second group, solid‐phase microextraction techniques such as in‐tube solid‐phase microextraction, stir bar sorptive extraction, dispersive solid‐phase extraction, dispersive micro solid‐phase microextraction, and microextraction by packed sorbent are highlighted. These approaches, in common, aim the determination of analytes at low concentrations in complex matrices. This article describes some characteristics, recent advances, and trends on miniaturized sample preparation techniques, as well as their current applications in food, environmental, and bioanalysis fields.     

An Intrinsic Photothermal Liquid for Light Detection and Energy Storage

Photothermal materials (PTMs) have been intensively investigated in the fields of photothermal conversion. Superior to solid PTMs, liquid PTMs are leading the trends in satisfying the demands of high flexibility and easy recycling. Successful examples of liquid PTMs are mostly formulated by dispersing solid PTMs in solvents, but suffer from the problems of phase segregation and solvent pollution. In this work, a low-cost formulation is proposed, which involves an oxidative product of ethyl oleate by iodine. It is an intrinsic liquid PTM, preserving the fluidic nature as well as possessing considerable ability for photothermal conversion. In addition to understanding the mechanism of light absorption in the visible and even near infrared windows, two examples are presented to demonstrate the great potential of liquid PTMs in broad areas such as light sensing and energy storage.     

Synthesis of cyclopentyloxy terphenyl liquid crystals with negative dielectric anisotropy

Liquid crystalline materials possessing negative dielectric anisotropy (Δε) have attracted considerable attention because they can be used to formulate eutectic mixture for several display applications. The negative Δε can be achieved by introducing a lateral polar substituent onto the mesogen core of a liquid crystalline material, and fluorine atoms are usually used because of the small size and high electronegativity. 2,3-ortho-Difluoro substituent liquid crystals exhibit stable and profound physical properties such as the low viscosity, strong negative Δε, and high solubility. To avoid the decrease of the mesophase range, 2,3-ortho-difluorophenyl is often placed next to the terminal chain. In this paper, we have synthesised a new series of 2,3-ortho-difluoroterphenyl liquid crystals with a negative dielectric anisotropy. Ether oxygen is introduced to the structure because it can further increase the lateral dipole moment. 3-Alkylcyclopentane end group decreases both the melting point and the viscosity, which makes it an appropriate substituent for negative Δε 2,3-ortho-difluoroterphenyl liquid crystals. The mesomorphic properties as well as the optical anisotropies of the synthesised liquid crystals are discussed in this paper. All compounds in the series are found to possess highly negative dielectric anisotropy, wide mesophase ranges; therefore, they have a great potential to formulate eutectic mixture for liquid crystal displays.     

Liquid hydrocarbon rubbers and their fields of application

The classification of liquid rubbers with terminal functional groups depending on their composition and structure is presented. Polydieneurethanes, as well as liquid rubbers with terminal carboxylic groups, are of the greatest interest for industry. The particular variants of applications of modified liquid rubbers for producing sealants, adhesives, compounds, and protective coatings with unique properties are presented.     

Clean-up techniques in the pressurized liquid extraction of abiotic environmental solid samples

Pressurized liquid extraction (PLE) uses high pressure and temperature to perform exhaustive extraction and is one of the extraction techniques widely used for determining contaminants in environmental solid samples. However, under these conditions, compounds from the matrix are also extracted. Therefore, clean-up strategies must be often applied to remove interferences and avoid matrix effect in the subsequent determination. There are different clean-up strategies that can be used in PLE, some of which are applied during the extraction procedure and some are applied to the PLE extract. The aim of this review is to critically discuss these clean-up techniques used in PLE of abiotic environmental solid samples in the last 10 years. We provide the readers with information about the weaknesses and strengths of each strategy so they can select the most suitable clean-up technique for a specific environmental analytical problem.     

Ultrafast,electric field-induced fingers in an anticlinic liquid crystal

Propagating fingers of synclinic liquid crystalline phase were observed to invade the anticlinic phase for applied electric fields E larger than a characteristic threshold field E_th. The front velocity was found to be highly non-linear in E, with enormous velocities of at least 10 cm s^-1, and perhaps as high as 400 cm s^-1 for the maximum applied field. These are by far the largest velocities ever observed for a liquid crystal. The results are discussed theoretically, including the possibilities of a field-dependent molecular interaction coefficient and shear thinning.     

Surface force spectroscopy of elastomeric nanoscale films

We studied nanomechanical properties for a series of ultrathin films of elastomeric materials from polyisoprene rubbers and tri‐block styrene‐butadiene‐styrene copolymer, SEBS. As we observed, the Hertzian approximation for elastic mechanical deformation of double layer films can be used for the analysis of force‐distance data at modest indentation depths and film thickness higher than 3 nm. For thinner films, the influence of solid substrate becomes very significant. On the other hand, the applicability of the Hertzian approximation is limited by the rate dependent elastomeric deformation. We demonstrated that Johnson modification of the contact mechanics model that includes a viscoelastic contribution could be utilized to obtain reasonable fitting of loading data for elastomeric materials.     

Study of properties of vulcanizates of modified binary mixtures of polar rubbers with polyisoprene

Influence of a modifying agent (trichloroacetic acid) on strength, elastic relaxation, and thermal properties of vulcanizates based on binary mixtures of polar rubbers with polyisoprene was studied.     

脉冲激光轰击固体靶制备纳米材料

综述了近年来脉冲激光轰击固体靶制备纳米材料。按介质种类和性质,脉冲激光轰击固体靶制备纳米材料的方法可分为六种:在气相、静态液相、动态液相三种惰性状态及其反应性状态下的反应。本文对以上六种制备方法及其优缺点作了较详细的阐述。其中最近发展起来的脉冲激光轰击处于流动液相中固体靶技术具有明显的优势,所制得的纳米产物分布均匀,重现性高,适用范围广泛。通过改变靶材和流动相的组分可制备各种各样具有新奇光、电、磁特性的纳米材料或纳米杂化材料,因而该技术有望成为脉冲激光轰击固体靶技术的一个重要的发展方向。