光响应性二芳基乙烯聚合物研究进展

二芳基乙烯(简称二芳烯)作为一种新的光响应化合物,具有非常好的热稳定性和抗疲劳性能.在不同波长的光(如紫外光和可见光)的作用下,二芳烯化合物会发生开环体与闭环体之间的光致可逆转变.这种开环体与闭环体之间的转变会引起化合物颜色的显著变化,同时还会引起化合物各种性质,如折射率、介电常数、氧化-还原电势的可逆变化,因此二芳烯...     

含氟磺化双三蝶烯型聚芳醚砜质子交换膜的制备及性能

利用3,3,4,4-四氟二苯砜、十氟联苯、6F-双酚A及6,13-双三蝶烯二酚,通过亲核取代共聚及后磺化方法制备了2个系列不同磺化度的磺化双三蝶烯型聚芳醚砜,并通过氢核磁共振波谱(1H NMR)对其化学结构进行了表征.研究发现,所得磺化聚芳醚砜均表现出了优异的热稳定性.此类膜材料具有优良的机械性能、尺寸稳定性、氧化稳定性及高温低湿度条件下高的质子传导率.透射电子显微镜的结果表明,聚合物主链中大量氟原子的引入显著改善了聚合物的相分离结构,并且随着聚合物主链中氟含量的增加,亲水区域明显增大.这也是含氟磺化双三蝶烯型聚芳醚砜质子交换膜材料在高温低湿度条件下具有高质子传导率的主要原因.     

O2促进下五元环烯胺的C—H亚胺化(英文)

报道了一个O₂促进下五元环烯胺的C—H亚胺化反应.在微波辐射下,季酮酸或1,3-环戊二酮衍生的烯胺酮、芳酮醛水合物和芳胺三组分参与的无金属催化反应进展顺利,以良好的产率和完全的立体选择性得到了一系列α-烯胺基-α-芳酰基亚胺衍生物.在该反应过程中,空气充当绿色氧化剂,水是唯一的副产物.     

氮桥双共轭体系共轭阻断效应AM1研究

利用AM1方法研究了氮桥双共轭体系共轭阻断效应，在蒋明谦先生等的研究基础上，用HOMO中烯醛或芳环成分能形象地说明芳环与烯醛共轭竞争。在氮桥的二边，一个双键及一个烯醛基共轭程度大致与二个芳稠环相当。     

移动阴极式掩膜电解加工微沟槽阵列均匀性研究

掩膜电解加工是一种高效率、大规模加工微结构的特种加工方法。然而,由于电流分布的边缘效应,在微结构的掩膜电解加工过程中往往存在着严重的加工尺寸不一致问题。针对这一问题,本文提出了一种移动阴极式掩膜电解加工方法。首先,利用COMSOL有限元分析软件对微沟槽阵列掩膜电解加工过程中的电流分布和阳极轮廓形状进行了数值仿真。仿真结果表明,相对于常规阴极结构的掩膜电解加工,采用移动阴极结构的掩膜电解加工方法能够获得尺寸更加均匀的微沟槽阵列结构。其次,在数值仿真的基础上,开展了掩膜电解加工实验研究。实验结果表明,移动阴极式掩膜电解加工方法能够有效地改善微沟槽阵列加工的尺寸均匀性。相对于常规阴极结构的掩膜电解加工过程,移动阴极式掩膜电解加工微沟槽阵列的均匀性提高了68.3%,并且随着阴阳极间距的增大,微沟槽深度不均匀度呈现出先减小后增大的趋势。随着阴极宽度的增大,微沟槽深度不均匀度逐渐增大;随着阴极移动速度的增大,微沟槽深度不均匀度逐渐减小,仿真与实验结果趋势一致。     

氢氧化铯催化二硫醚、二碲醚与端炔反应研究

氢氧化铯催化下, 以商业THF作溶剂, 在氮气氛中二芳基二硫醚与端炔室温反应, 立体选择地生成(Z)-1,2-二芳硫基烯. 在空气氛中反应, 得到(Z)-1,2-二芳硫基烯与炔硫醚的混合物. 二芳基二碲醚与端炔反应, 不论在氮气氛中或空气氛中, 都只产生炔碲醚. 但是在氮气氛中炔碲醚的收率仅为空气氛中反应的50%, 对上述反应机理进行了讨论.     

无溶剂法合成杯[4]芳烯星形化合物

以对苯二甲醛、乙酸酐为原料合成对苯二甲醛单缩醛, 接着与间苯二酚反应, 制备了含醛基杯[4]芳烯. 利用季戊四醇与含醛基杯[4]芳烯反应, 进而再与3-[4-(2,5-二氧杂环戊基)苯基]-9-[4-二(甲羰氧基)甲基苯基]-2,4,8,10-四氧杂螺环[5.5]十一烷反应, 合成了杯[4]芳烯星形化合物, 收率为65.2%. 产品结构经 IR, ¹H NMR, MS 和元素分析进行了表征.     

1－芳酰基－3－烷基－6－羟基－6－芳基富烯的合成

１－芳酰基－３－烷基－６－羟基－６－芳基富烯的合成焦纶基,董育斌,马玉道（山东大学应用化学研究所,济南,２５０１００）关键词富烯,二茂铁,芳酰化,合成前文［１］曾报道过甲基锂、苯基锂与６,６－二烷基富烯加成物的芳酰化。为进一步探讨取代环戊二烯负离子的...     

取代环戊二烯基锂芳酰化的研究

本文研究了由616-二烷基富烯与有机锂所制得取代环戊二烯基锂和芳酰氯的反应,合成了二十个未见文献报道的新富烯类化合物,并通过^1HNMR、IR和元素分析确定了它们的结构.     

芳醚树枝形聚合物的合成及分子内光敏异构化反应研究

利用收敛法合成了一代到四代外围带有二苯酮、核心带有降冰片二烯的芳醚树枝形聚合物, 初步研究了这些化合物的分子内光敏异构化反应. 以波长大于350 nm的光选择激发外围的二苯酮官能团引起核心处降冰片二烯基团异构化为四环烷, 随着代数的增长, 光敏异构化反应的速率逐渐加快.     

一种具有光致变色特性的膜蛋白/聚合物复合膜

通过基因工程技术将古紫质4(archaerhodopsin-4,AR4)膜蛋白的基因转入本身不表达该蛋白质、也不表达玉红素的嗜盐菌株L33中,去除了天然菌株xz515所获得的AR4膜蛋白脂环境中的玉红素,优化了AR4的光致变色性能.将重组古紫质4包埋于聚乙烯醇中制成复合膜,并通过提高体系的pH值,延长了M态的寿命,进一步实现了简单图案记录,验证了该活性蛋白质与聚合物的复合材料具有光信息存储功能.     

Leaching of Celestite in Sodium Hydroxide Solutions and Kinetic Modelling

In this study, the dissolution kinetics of celestite in solutions of sodium hydroxide was investigated by batch process. The results showed that the parameters which had the greatest effect on the dissolution of celestite in sodium hydroxide solutions were reaction temperature, the concentration of sodium hydroxide and stirring speed. It was determined that the dissolution rate increased with increased stirring speed, sodium hydroxide concentration, reaction time and temperature and decreased with increasing particle size and solid-liquid ratio. The leaching process fitted the shrinking core model with diffusion through the product layer model as the rate-determining step. The activation energy of the dissolution of celestite was calculated as 62.24?kJ/mol. A semi-empirical kinetic model was obtained for dissolution of celestite in sodium hydroxide solution.     

Formation of masking pattern by electron beam-induced vapor deposition

The dry resist-free process of electron beam-induced masking via chemical vapor deposition from a hydrocarbon precursor was studied. It was shown that the obtained mask exhibited a low selectivity during ion beam etching with SF₆ ions. It was found that, during mask deposition, a thin (of the order of 1 nm) boundary layer is formed on the SiO₂ plate surface; the layer had a substantially higher plasma resistance and, hence, high selectivity upon ion beam etching of SiO₂. Certain features of the masking process and the properties of the mask material were studied.     

Protecting structure analyses of organic molecule-protected nanoscopic noble metal clusters

The stabilizing structure of cationic surfactant-protected platinum clusters in water and tertiary amine-protected rhodium clusters in chloroform, prepared by photo- and hydrogen-reduction, respectively, was investigated. These nanoscopic noble metal clusters present a narrow size distribution and are stable. The structural information of protective organic molecules on the surface of metal clusters was studied by transmission electron microscopy and hydrodynamic radius measurements according to the Taylor dispersion method. The size of the entire cluster with the protective layer surrounding the metal surface, obtained as Stokes' radii by the Taylor dispersion method, is considered to be fairly consistent with the sum of the naked particle size, obtained by transmission electron micrographs, and the size of the adsorbed protective layer, supporting the conformational information.     

Membrane formation by water vapor induced phase inversion

The membrane formation by the phase inversion process was studied by coagulating a polysulfone/N-methyl-2-pyrrolidone solution with water vapor as a coagulant. The phase separation occurred when the relative humidity in the membrane casting atmosphere was higher than about 65%. The pore size was strongly affected by the relative humidity as well as the concentration of the polymer solution. It increased as both the relative humidity and the polymer concentration were decreased. The membranes produced showed a uniform structure composed of closed pores. The pure water flux measurement confirmed the closeness of the pores. The information on the late stage phase separation was obtained in situ by an optical microscope due to the slow phase separation. The pores seemed to grow very much at the late stage by coarsening which was observed to occur mainly by coalescence of polymer-lean droplets. As the relative humidity was lower, the coarsening continues longer ending up to a larger droplet size. The coarsening seems to enhance the interconnectivity of pores when the polymer concentration was low enough.     

Mask‐Like Symmetrical Microclusters through a Diffusion‐Limited Assembly Approach

A diffusion‐limited assembly approach was explored to fabricate symmetrical [Cu(Succinate)]_n microclusters with a different shape and size for the first time. The molecular structure of succinate and its coordination reaction capability towards copper(II) ions governed the one‐dimensional growth of the nanofibers and the concomitant formation of the microclusters. In detail, a symmetrical concentration gradient was formed around the endpoints of the nanofibers caused by the diffusion‐limited process at high reactant concentrations. The concentration gradient forced the nanofibers to grow divergently and further aggregate into open microcluster structure. The shape and size of the microclusters could be tuned by altering the concentration of the reactants. Particularly, mask‐like double‐hole symmetrical microclusters (MDHSMs) were obtained when the concentration of both reactants was as high as 140 mM . The resultant MDHSMs showed high selectivity in adsorption of dyes and proteins, and may find potential applications in water treatment, bioseparation, and immobilization of biomacromolecules.     

Effects of Pellet Characteristics on L-Lactic Acid Fermentation by R. oryzae: Pellet Morphology,Diameter, Density,and Interior Structure

The effects of pellet morphology, diameter, density, and interior structure on L-lactic acid fermentation by Rhizopus oryzae were characterized for different inoculum sizes and concentrations of peptone and CaCO₃. Inoculum size was the most important factor determining pellet formation and diameter. The diameter decreased with increasing inoculum size, and larger pellets were observed for lower inoculum sizes. Peptone concentration had the greatest effect on pellet density, which increased with increasing peptone concentration. L-lactic acid production depended heavily on pellet density but not on pellet diameter. Low-density pellets formed easily under conditions of low peptone concentration and often had a relatively hollow structure, with a thin condensed layer surrounding the pellet and an extraordinarily loose biomass or hollow center. As expected, this structure greatly decreased production. The production of L-lactic acid increased until the density reached a certain level (50–60 kg/m³), in which the compact part was distributed homogeneously in the thick outer layer of the pellet and loose in the central layer. Homogeneously structured, denser pellets had limited mass transfer, causing a lower overall turnover rate. However, the interior structure remained nearly constant throughout all fermentation phases for pellets with the same density. CaCO₃ concentration only had a slight influence on pellet diameter and density, probably because it increases spore germination and filamentous hypha extension. This work also provides a new analysis method to quantify the interior structure of pellets, thus giving insight into pellet structure and its relationship with productivity.     

Preparation of polysaccharide-coated nanoparticles by emulsion polymerization of styrene

It is the aim of this paper to describe the preparation of polysaccharide-coated nanoparticles by direct emulsion polymerization of styrene in the presence of native dextran. In spite of the lack of surface-active properties of native dextran, stable latexes with very low amount of coagulate were obtained. Particle size decreased with dextran concentration and molecular weight. The amount of permanently adsorbed dextran was determined by direct titration of the polysaccharide present on the surface of the nanoparticles. A maximum value of 2.5 mg m⁻² was found. Zeta-potential measurements allowed us to estimate the thickness of the hydrophilic layer, which regularly increased with dextran aqueous concentration. The dextran-coated polystyrene nanoparticles were stable in concentrated NaCl solutions and could be redispersed after freeze-drying. The mechanism of chemical modification of dextran was studied by nuclear magnetic resonance and matrix-assisted laser desorption/ionization-time of flight spectrometry studies. Graft copolymers are supposed to be formed.     

Preparation and characterization of mono-valent ion selective polypyrrole composite ion-exchange membranes

Polypyrrole composite cation- and anion-exchange membranes (CEM and AEM), in which polypyrrole (PPY) coated on one surface of the membrane as a thin layer, were prepared by chemical polymerization of pyrrole in the presence of high oxidant concentration (Na₂S₂O₈). Existence of polypyrrole layer on the both types of ion-exchange membranes were confirmed by recording their coating density, SEM images and conductivity. These membranes were extensively characterized by recording their properties such as water uptake, ion-exchange capacity, contact angle, permselectivity and membrane conductivity as a function of polymerization time such as. It was observed that due to coating of PPY for 2 h, membrane permselectivity of CEM for NaCl (0.907) was reduced to 0.873, while it was increased from 0.747 to 0.889 in the case of AEM. Similar behaviors were also obtained for bi-valent electrolytes. Electrodialysis experiments were also conducted with polypyrrole composite ion-exchange membranes using mixed electrolytic systems. Relative dialytic rates for NaCl with respect to other bi-valent electrolyte were varied in between 5 and 8 (depending on bi-valent electrolyte), which suggested the feasible and efficient separation of mono-valent from bi-valent electrolyte. Slower electro-migration of bi-valent electrolyte (CaCl₂, MgCl₂ and CuCl₂) in comparison to NaCl was explained on the basis of synergetic effect of sieving of bulkier bi-valent cations by tight and rigid polypyrrole layer and the difference in electrostatic and hydrophobic–hydrophilic repulsion force between bi-valent cations and mono-valent cation. It was concluded that these composite membranes are suitable for the efficient separation of same type of charged ions by electro-driven separation techniques.     

聚合物光盘基板材料的研究进展

光盘是一种以非接触方式记录/再现信息的信息记录介质,主要由基板、记录层和保护层组成。其中,基板材料所用的光学塑料是光盘生产的主要原材料,对光盘的性能和成本构成至关重要。本文综述了聚合物光盘基板材料的研究现状及其发展趋势。光盘基板材料主要包括传统的聚碳酸酯（PC）,聚甲基丙烯酸甲酯（PMMA）、环氧树脂以及近年发展起来的非晶环烯烃聚合物。研制具有较低的双折射、吸湿性、固化成型收缩率以及较高的存储密度和存储寿命的光盘基板材料是聚合物光盘基板材料的一个重要研究领域。