共查询到20条相似文献,搜索用时 0 毫秒
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Kaushik Mallick Mike J. Witcomb Andy Dinsmore Mike S. Scurrell 《Macromolecular rapid communications》2005,26(4):232-235
Summary: We report a new method for the preparation of polyaniline nanoballs by using HAuCl4 as an oxidizing agent. During the reaction, aniline is oxidized and forms polyaniline whilst the hydrogen tetrachloroaurate is reduced and forms gold nanoparticles. These gold nanoparticles are found to decorate the nanoballs.
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Summary: Free radical emulsion polymerization of styrene (S) or butyl acrylate (BA) in the presence of latices of linear polyethylene (PE) prepared by catalytic emulsion polymerization affords colloidally stable multiphase latices. Coagulation of a PE/PS latex affords nanocomposites composed of small PE phases dispersed in a PS matrix, as evidenced by the large supercoolings of PE crystallization (by DSC). TEM of PE/PBA latices indicates a PBA phase around the PE particles under the emulsion polymerization conditions investigated. Films formed from these dispersions exhibit homogeneously dispersed PE particles.
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以苯胺二聚体(N-phenyl-p-phenylenediamine)为起始单体,在1 mol·L-1高氯酸水-乙腈混合液中,玻碳电极表面电化学制备聚苯胺. 实验结果表明,苯胺二聚体单体的聚合电位比苯胺单体的低约0.2 V,并且其聚合物具有更高的形貌可控性. 苯胺二聚体单体浓度分别为1、5和10 mmol·L-1时,采用分步恒电流法可分别制备出形貌均一的聚苯胺纳米粒子(粒径30 nm)、超长的纳米线(> 5 μm 直径50 nm)和大面积纳米片(4 μm × 2 μm × 30 nm). 相似文献
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Duk Ki Kim Kyung Wha Oh Seong Hun Kim 《Journal of Polymer Science.Polymer Physics》2008,46(20):2255-2266
The composite of polyaniline (PANI) and multiwall carbon nanotube carboxylated through acid treatment (c‐MWCNT) was synthesized by chemical oxidative polymerization in an inverse emulsion system. The resultant composites were compared with products from aqueous emulsion polymerization to observe the improvements in electrical conductivity, structural properties, and thermal stability obtained by this synthetic method. Prior to the inverse emulsion polymerization, MWCNT was treated with a strong acid mixture to be functionalized with carboxylic acid groups. Carboxylic acid groups on surfaces induced selective dispersibility between polar and nonpolar solvents because of the increase of hydrophilicity. As the content of c‐MWCNT was increased, the electrical conductivity was increased by a charge transport function from the intrinsic electrical conductivity of MWCNT and the formation of a highly ordered dense structure of PANI molecules on the surface of c‐MWCNT. The images observed with electron spectroscopy showed the capping of c‐MWCNT with PANI. The growth of additional ordered structures of PANI/c‐MWCNT composite, which was observed through wide‐angle X‐ray diffraction patterns, supported the capping by PANI. It was observed that the doping of the composite had a significant relationship with the concentration of dodecylbenzenesulfonic acid (DBSA). The thermal stability of PANI composite was improved by the addition of c‐MWCNT; this was thought to be related with structure ordering by inverse emulsion polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2255–2266, 2008 相似文献
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Ovsyannikova E. V. Grosheva M. Yu. Alpatova N. M. 《Russian Journal of Electrochemistry》2004,40(10):1089-1091
A cyclic voltammetry study shows the anodic polymerization of aniline in 2 M HClO4 water–acetonitrile solutions to proceed via an EC: EC mechanism. In the chemical reaction, pernigraniline catalyzes the aniline oxidation, recovering from emeraldin in the second stage of the electrochemical process. 相似文献
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影响苯胺电化学计量聚合因素的探讨 总被引:5,自引:0,他引:5
本文对影响苯胺电化学计量聚合的因素进行了探讨,这些因素包括:电化学聚合方法、电极电位(E)、电流密度(I),以及苯胺单体和酸溶液的浓度等,实验结果表明,最合适的聚合方法为恒电流法,其条件为:电极电位不大于0.70V(vs.SCE)聚合电流密度(I)约为0.05mA/cm^2,苯胺单体浓度为1.1mol/L,酸(HCl)的浓度则为2.2mol/L 相似文献
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聚苯胺膜电极在苯胺单体聚合反应中的电催化性能 总被引:4,自引:0,他引:4
自从第一个导电高聚物掺碘的聚乙炔问世以来[1],人们又陆续开发研制了聚 苯胺(PAn)、聚吡咯和聚噻吩等导电高分子材料. 在众多的导电高分子材料中,聚苯胺以其原 料廉价易得,制备方法简便,导电性能优良,耐高温及抗氧化性能良好等优点而成为最具应用 前景的品种之一. 迄今为止,有关聚苯胺的链结构,掺杂反应,以及导电机理等基础理论方面 的研究已有大量的文献和综述报道[2~6]. 这些基础理论的研究为其应用研究奠定 了坚实的基础. 早在60年代,人们就发现,聚苯胺对氧化亚氮分解及丁二烯异构化反应具有独 特的催化作用;同时,聚苯胺具有超出几何表面的活性表面,故可对某些反应具有选择性的催 化作用. 因此,人们开始研究聚苯胺膜电极对某些电极反应的电催化性能[7~12]. 我国科学工作者在这一领域也做了许多有益的工作,如董绍俊等[13]研究了聚苯胺 膜修饰电极对抗坏血酸的电催化氧化,罗维忠等[14]研究了聚苯胺膜电极对Fe(Ⅱ) 和Sb(Ⅲ)的电催化作用. 本文主要讨论了扫描速度、苯胺单体浓度及温度对聚苯胺膜电极在 苯胺单体聚合过程中电催化性能的影响,为利用聚苯胺处理含苯胺废水提供了一定的理论依 据. 相似文献
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《化学:亚洲杂志》2017,12(16):2057-2061
The catalytic polymerization of ethylene is performed in water pressurized with CO2. The size of the initial monomer droplets and of the resulting polymer particles can be varied by simply changing the CO2 pressure. Furthermore, at identical ethylene partial pressure, the polymerizations performed in the presence of CO2 are significantly faster than in its absence. Thus, the combination of CO2 and water is a promising green solvent for catalytic emulsion polymerizations. 相似文献
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Chi‐an Dai Chun‐jie Chang Hung‐yu Chi Hung‐ta Chien Wei‐fang Su Wen‐yen Chiu 《Journal of polymer science. Part A, Polymer chemistry》2008,46(7):2536-2548
Poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) is a widely used conductive aqueous dispersion synthesized by using emulsion polymerization method. To further enhance its solution processability and conductivity of PEDOT derivatives, we proposed to replace the nonconductive PSS with conductive poly[2‐(3thienyl)‐ethoxy‐4‐butylsulfonate] (PTEB) as surfactant for the emulsion polymerization of PEDOT. The reaction involved colloid stabilization and doping in one step, and yielded PEDOT:PTEB composite nanoparticles with high electrical conductivity. Contrary to its counterpart containing nonconductive surfactant, PEDOT: PTEB showed increasing film conductivity with increasing PTEB concentration. The result demonstrates the formation of efficient electrical conduction network formed by the fully conductive latex nanoparticles. The addition of PTEB for EDOT polymerization significantly reduced the size of composite particles, formed stable spherical particles, enhanced thermal stability, crystallinity, and conductivity of PEDOT:PTEB composite. Evidence from UV–VIS and FTIR measurement showed that strong molecular interaction between PTEB and PEDOT resulted in the doping of PEDOT chains. X‐ray analysis further demonstrated that PTEB chains were intercalated in the layered crystal structure of PEDOT. The emulsion polymerization of EDOT using conducting surfactant, PTEB demonstrated the synergistic effect of PTEB on colloid stability and intercalation doping of PEDOT during polymerization resulting in significant conductivity improvement of PEDOT composite nanoparticles. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2536–2548, 2008 相似文献
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报道了一种高溶解性导电聚苯胺(PANI)的制备方法,以聚2-丙烯酰胺-2-甲基丙磺酸(PAMPS)作为掺杂酸和乳化剂,利用其特有的长链、亲水性及强酸性基团效应,通过乳液聚合法一步合成出具有较高溶解性的导电聚苯胺。利用核磁共振光谱仪(NMR)、傅里叶红外光谱仪(FT-IR)和扫描电子显微镜(SEM)等技术手段对产物结构和性能进行了表征分析。结果表明,在m(苯胺)∶m(AMPS)∶m(APS)=1∶2∶1.5;AMPS质量分数为20%;APS质量分数为30%;反应时间为5 h;反应温度为5℃的条件下,聚苯胺的产率高达86%,在有机溶剂二甲基甲酰胺(DMF)中的溶解度可达0.3814 g/g,在水中的溶解度可达0.2123 g/g,电导率达5.9 S/cm。 相似文献
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苯乙烯微乳液种子聚合 总被引:21,自引:1,他引:20
通过观测苯乙烯微乳液种子聚合前后体系内聚合物粒子大小及其分布的变化发现,无论是γ射线还是KPS引发,聚合过程中都没有新的聚合物粒子生成。尽管聚合前体系中存在单体溶胀的胶束,但在聚合过程中这些胶束主要充当单体仓库,自己成核聚合的几率很低。由于微乳液种子聚合体系内,单体量相对较低,聚合物粒子数目很大,其聚合动力学明显不同于常规乳液种子聚合。 相似文献
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Stefan Mecking Anke Held Florian M. Bauers 《Angewandte Chemie (International ed. in English)》2002,41(4):544-561
Catalytic conversions in aqueous environments by transition metal complexes have become a well‐established field over the past two decades. However, the vast majority of investigations have focussed on small‐molecule synthesis. This may appear somewhat surprising as water is a particularly attractive reaction medium, especially for polymerization reactions. For example, aqueous emulsion and suspension polymerization is carried out today on a large scale by noncatalytic free‐radical routes. Polymer latices can be obtained as a product, that is, stable aqueous dispersions of polymer particles in the size range of 50 to 1000 nm. Such latices possess a unique property profile. Amongst other advantages, the use of water as a dispersing medium is particularly environmentally friendly. In comparison to these free‐radical reactions, aqueous catalytic polymerizations of olefinic monomers have received less attention. However, considerable advances and an increased awareness of this field have emerged during the past few years. A variety of high molecular weight polymers ranging from amorphous or semicrystalline polyolefins to polar‐substituted hydrophilic materials have now been prepared by catalytic polymerization of olefinic monomers in water. Polymer latices based on a number of readily available monomers are accessible and catalytic activities as high as 105 turnovers per hour have already been reported. As another example, materials prepared by aqueous catalytic polymerization have been investigated as protein inhibitors. A versatile field spanning colloids, polymer, and coordination chemistry has emerged. 相似文献
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用透射电镜(TEM)对苯乙烯(St)/十二烷基硫酸钠(SDS)/正戊醇/水的O/W微乳液体系在反应前、聚合过程中和反应结束后等不同时间里进行观察,并测定苯乙烯微乳液聚合前后粒径的大小,根据粒径大小的变化研究苯乙烯微乳液聚合成核机理,发现其成核位置主要是在胶束和单体微珠滴里。此外,还发现SDS/St的质量比越大,相对分子质量越低。 相似文献
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Stefan Mecking Vincent Monteil Johannes Huber Ludmila Kolb Peter Wehrmann 《Macromolecular Symposia》2006,236(1):117-123
The preparation of aqueous dispersions of very small particles (size < 30 nm) of various polymers (polyethylenes, stereoregular 1,2-polybutadiene, and polyalkenamers) by catalytic polymerization with a water-soluble catalyst, or with microemulsions of lipophilic catalysts is reviewed. 相似文献