聚邻苯二胺膜电极的性能及其对苯醌还原动力学的影响

利用循环伏安法和原位红外反射光谱法研究了pH=7.0的磷酸盐缓冲溶液中聚邻苯二胺(PPD)膜电极的电化学行为。在比0.0V(SCE)负的电位区,PPD呈现氧化还原活性,氧化还原过程伴有H₂PO₄^-离子的嵌入和脱出,证明聚合物带有正电荷。苯醌在该膜电极上的还原反应发生在PPI)的电化学活性电位区内。旋转圆盘电极实验表明,苯配可渗入膜内并与聚合物交换电子。根据PPD为导电聚合物的模型分析了膜电极上苯配还原的动力学并讨论了对其影响的因素。     

聚乙撑二氧噻吩的导电性及现场ESR响应的研究

聚乙撑二氧噻吩(PEDOT)因为具有很高的稳定性和导电性，近年来受到了广泛 的注意并开始在许多方面得到实际应用．电化学聚合方法具有操作简便、易于控制 等优点．本文采用恒电位电化学聚合方法，在水溶液中Pt电极上制备了聚乙撑二氧 噻吩．研究了单体浓度、支持电解质种类、聚合电位等因素对聚合得到的PEDOT膜 导电性的影响．首次运用电化学现场ESR技术研究了水溶液中PEDOT膜的ESR响应， 结合电化学现场的膜电阻测量研究了PEDOT膜的导电性随所加电位的变化规律．结 果表明，PEDOT膜随不同电位的导电性的变化规律符合极化子—双极化子理论．     

聚乙撑二氧噻吩阳极降解的研究

研究了聚乙撑二氧噻吩(PEDOT)膜在水溶液中的阳极降解过程. 研究发现PEDOT的阳极过程可以分为p掺杂区[电位范围－0.3～0.5 V (相对于饱和甘汞电极; vs. SCE)]、过渡区[电位范围0.6～1 V (vs. SCE)]、过氧化区[电位范围1.2～1.6 V (vs. SCE)]三个电位区域. 用电化学阻抗谱法、循环伏安法、红外光谱技术、膜电阻测量以及电子自旋共振技术分别研究了PEDOT膜在这三个电位区域的行为. 结果表明: PEDOT膜在这三个电位区域的性质有明显不同. 在p掺杂区PEDOT膜的官能团、共轭结构、导电性均保持, 即在这个电位区发生可逆的掺杂/脱掺杂反应, 膜几乎不降解. 在过渡区和过氧化区, PEDOT膜均发生了降解. 与传统的导电聚合物在高电位的阳极降解的过氧化过程不同, 我们认为膜在较高电位(过渡区)发生一个驰豫过程, 该过程使得膜的官能团改变, 但是膜的共轭结构和导电性均保持; 而在更高的电位区(过氧化区)膜的降解和一般意义的过氧化降解相同, 此时膜的官能团、共轭结构、导电性均发生不可逆的破坏.     

聚甲苯胺蓝-(多壁碳纳米管/PDDA)n杂化膜修饰电极的制备及其对NADH的催化氧化

导电聚合物修饰电极由于聚合物结构致密,限制了底物在聚合物膜中的渗透,且随着膜厚的增加其导电能力逐渐减弱.碳纳米管在导电聚合物中的掺杂明显改善了导电聚合物的导电性~([1]).但是碳纳米管的水溶性差及纳米尺寸带来的聚集效应,使得通过主体聚合制备杂化膜的过程中容易出现相分离进而影响到杂化膜的性质~([2]).     

间甲基苯胺电化学聚合以及它与对苯二胺电化学共聚的 原位紫外-可见光谱

在0.5 mol•dm－3硫酸介质中, 循环伏安法电解间甲苯胺的原位紫外可见光谱图表明聚间甲基苯胺产生在氧化铟锡导电玻璃电极表面上. 在恒电位条件下, 用原位紫外-可见光谱较详细地研究了间甲基苯胺在氧化铟锡(ITO)上的电化学聚合. 结果表明间甲基苯胺只能在较高电解电位和单体浓度足够大的条件下才能发生电化学聚合. 在0.7 V(相对于饱和的Ag/AgCl), 0.2 mol•dm－3的间甲基苯胺和0.9 V, 20 mmol•dm－3的间甲基苯的实验条件下, 尽管在ITO电极上没有发生电化学均聚合, 但原位紫外-可见光谱表明在电极表面上可能还形成低分子量的齐聚物. 在低电位0.8 V下, 电化学聚合200 mmol•dm－3间甲苯胺时, 有明显的诱导期存在. 在恒电位电解的条件下, 相应的原位紫外-可见光谱和聚合物的傅立叶变换红外光谱(FTIR)表明间甲基苯胺和对苯二胺能发生电化学共聚反应, 由于对苯二胺可能与间甲基苯胺形成了具有较强反应活性的中间体, 使得对苯二胺的加入不但促进和加速了聚合反应, 而且还结合进聚合物中形成了phenazine或类似于phenazine的环结构.     

Corosion Potential Imagingat the InterfaceofCoating／MetalbyaNewElectrochemicalTechnique

在绝大多数环境下，聚合物／金属界面的腐蚀破坏的本质是电化学过程，因此，不少电化学技术，包括直流稳态技术和交流阻抗技术等被广泛用于研究金属／聚合物界面的腐蚀破坏机制，评测有机涂层的耐蚀性能．然而，由于聚合物／金属界面腐蚀破坏的“闭塞”条件和聚合物膜层的高绝缘性，传统的电化学方法均不能直接获得聚合物／金属界面二维空间的腐蚀电位分布，难以直接研究聚合物／金属界面的腐蚀破坏过程及相关的影响因素．聚合物／金属界面腐蚀电位的测量有助于研究聚合物／金属等复合材料界面腐蚀破坏机理，评测有机聚合物涂覆层的耐蚀性能．本文提出一种微计算机控制的阵列电极技术，用于原位测量金属／聚合物界面电位分布．首次建立了８×８阵列电极和微机控制的阵列电极测量系统，可直接测量聚合物／金属界面腐蚀电位的二维分布．由此可深入研究有关腐蚀物种在聚合物相内传输过程，聚合物涂层的不均一性及缺陷分布，以及聚合物／金属界面腐蚀的发生、发展机制．应用阵列电极技术首次在原位获得聚合物涂层的缺陷分布及不均一性，并考查了聚合物涂层缺陷对诱导聚合物／金属界面腐蚀破坏的关系．阵列电极技术还首次提供了在聚合物／金属界面腐蚀破坏发展过程中阴、阳极同时存在，共同发展的直接的     

蛋白质在导电聚甲基丙烯酰吡咯上的吸附

采用表面引发原子转移自由基聚合(SIATRP)技术在硅片及金膜表面上制备导电聚丙烯酰吡咯(PMAP),并对聚合物薄膜的化学结构等进行了表征.采用表面等离子谐振生化分析仪(SPR)原位考察了牛血清白蛋白(BSA)在聚合物表面上的吸附行为,通过改变缓冲液的pH值和BSA的浓度对蛋白质吸附的影响,探讨了BSA在PMAP上的吸附机理.采用电化学循环伏安测试考察了蛋白质吸附对于导电聚合物的电化学行为的影响.采用原子力显微镜(AFM)考察了BSA在聚合物表面上吸附前后聚合物的表面形貌变化.     

导电聚合物的电化学制备及其应用研究进展

导电聚合物由于具有结构特殊、环境稳定性好、成本低廉等优点而成为科学领域中极具应用前景的新型材料。本文综述了采用电化学聚合方法制备导电聚合物材料的国内外研究状况。电化学聚合方法是此类材料重要的制备方法之一。基于该方法的最新研究进展,本文系统地归纳了导电聚合物的恒电位法、恒电流法、动电位法、脉冲法等电化学聚合方法,并展望了导电聚合物纳米材料在超级电容器、太阳能电池、锂离子电池、电催化等领域的应用前景。     

导电聚合物的电化学制备和电化学性质研究——中国科学院有机固体重点实验室导电聚合物电化学研究工作简介(I)

简要介绍本研究组自上世纪80年代以来在导电聚合物的电化学制备和电化学性质研究中取得的一些主要成果,包括吡咯电化学聚合条件的影响、电化学聚合反应机理及其反应动力学、导电聚吡咯的两种掺杂结构及其两步电化学氧化还原过程和电化学过氧化的机理、导电聚苯胺的电化学性质、导电聚合物稳定性的电化学解释等等.     

导电聚合物的现场电导/电化学研究——聚(3-甲基噻吩)和聚噻吩

本文提出一种研究导电聚合物的现场电位、电导测量/电化学方法。该实验方法基于一种可重复使用的玻璃碳-碳纤维组双电极。用该方法研究了聚(3-甲基噻吩)和聚噻吩的现场电位、电导/电化学行为。     

Achieving highly crystalline rate and crystallinity in Poly(l-lactide) via in-situ melting reaction with diisocyanate and benzohydrazine to form nucleating agents

The drawback of the application for poly(_l-lactide) (PLLA) is the low crystalline rate and crystallinity obtaining via normal processing methods. Modifying crystallization of PLLA has been found to be an efficient way to improve its mechanical and heat resistance properties. In this wok, 4, 4′-diphenylmethane diisocyanate (M) and benzohydrazine (P) were employed into PLLA melt to in-situ form nucleating agents. The in-situ melting reaction was confirmed by a nuclear magnetic resonance spectroscopy. The crystallization behavior and crystalline morphology were investigated by a differential scanning calorimetry, a polarized optical microscopy and a field emission scanning electron microscope. The crystalline rate of PLLA was abruptly enhanced by adding (M+P) and melting reaction with PLLA. The crystallization half-time of PLLA dramatically decreased from 42.0 to 1.1 min at 130 °C by the in-situ formation of nucleating agents. The crystallinity of PLLA increased from 10.3 to 42.1 by adding 0.25% (M+P) and melting reaction for 8 min. Furthermore, the size of PLLA crystals was dramatically reduced because of the nucleating effect. Accompanied with improvement on crystallinity, the Vicat softening temperature of PLLA shifted from 57.4 °C to 93.7 °C by the in-situ reaction with 6.00% (M+P), and indicating heat resistance enhancement.     

PREPARATION AND CHARACTERIZATION OF ION EXCHANGE MEMBRANES BASED ON POLYVINYLIDENE FLUORIDE

A new ion exchange membrane based on polyvinylidene fluoride (PVDF) and sulfonated poly(styrenedivinylbenzene) was prepared by in-situ polymerization. The incorporation of sulfonic groups into the polyvinylidene fluoride composite membrane was confirmed by infrared spectroscopy (IR), ion exchange capacity (IEC) and energy dispersive X-ray analysis (EDAX). Area resistance, IEC and water uptake of the treated membrane were evaluated. When area resistance in NaCl aqueous solution at 25℃, IEC is as high as 2.43 millimoles per gram of the wet membrane. The hydrophilicity of PVDF membrane is also significantly improved after treatment. When 60% of crosslinked membrane was sulfonated at 80℃ for 6 h, water uptake of the treated membrane can attain 64.7%.     

原位聚合法制备聚醋酸乙烯酯/纳米SiO2复合乳液

采用原位乳液聚合法制备了聚醋酸乙烯酯／纳米二氧化硅复合浮液。用红外光谱、原子力显微镜以及透射电镜等现代测试手段对复合材料进行了表征．考察了纳米二氧化硅在聚醋酸乙烯酯乳液中的分散状况及纳米二氧化硅用量对复合浮液性能的影响。结果表明：随纳米二氧化硅用量增加,复合乳液的干态,湿态粘接强度均而明显提高;乳液的粘度减小;复合乳液的胶膜耐热性提高。     

橡胶-填料相互作用对丁苯橡胶/白炭黑复合材料性能的影响

本文研究了硅烷偶联剂原位改性白炭黑对溶聚丁苯橡胶(SSBR)性能的影响,结果表明,通过哈克转矩流变仪对含有偶联剂的SSBR/白炭黑混炼胶进行原位热处理后可明显减弱混炼胶的Payne效应,改善白炭黑在橡胶基体中的分散.原位热处理方法能够明显提高硫化胶的300%定伸应力,降低动态压缩温升,同时可使硫化胶在0℃附近具有较高的损耗因子(tanδ),60℃附近具有较低的tanδ.对不同聚合方式得到的丁苯橡胶,即溶聚丁苯橡胶与乳聚丁苯橡胶(ESBR)/白炭黑复合材料的力学性能及动态力学性能进行了研究,结果表明,白炭黑在SSBR2305中分散效果优于在ESBR1502中;采用偶联剂原位改性白炭黑可以使SSBR2305硫化胶获得与ESBR1502硫化胶相当的物理机械性能,更理想的动态力学性能,从而得到力学性能、抗湿滑性、滚动阻力及耐磨性更加均衡的理想轮胎材料.通过对具有不同偶联效率的SSBR/白炭黑体系的微观结构与性能研究发现,随偶联效率的增加,其结合橡胶含量增加,Payne效应减弱;高偶联效率的S-SBR具有较低的动态压缩温升及较好的耐磨性.     

A Single-Gallery Model for the In Situ Production of Polyethylene-Clay Nanocomposites

Polyolefin-clay nanocomposites are finding many new applications because of their improved properties, such as high modulus, elevated scratch resistance and low gas permeability. Currently, these composites are produced by melt blending organically modified clay with polyolefins. The most challenging step in this process is the intercalation and exfoliation of the clay to produce a homogenously dispersed phase at the nanoscale. A promising alternative to melt blending is in-situ polymerization, where the polymer is produced between the clay layers in the polymerization reactor. In-situ polymerization of olefins with metallocene catalysts supported on clay can produce nanocomposites using conventional polymerization reactors, provided that the clay can be used as a support for the olefin polymerization catalyst. In this approach, the clay fulfills the functions of catalyst support and dispersed phase in the final nanocomposite. In this work, a mathematical model describing particle growth during in-situ polymerization of ethylene with a metallocene catalyst supported on clay will be discussed. The model expands the approach of the multi-grain model used in heterogeneous olefin polymerization to account for the layered structure of clays.     

Characterization of multiple carbon fibre microelectrodes in a flow-through cell and amperometric detection with dilute electrolyte for liquid chromatography

A simple, convenient and sensitive flow-through cell incorporating multiple carbon fibres in a polyvinyl chloride tube was constructed for high performance liquid chromatography. The voltammetric behaviour, electrode treatment, stability and hydrodynamic voltammograms of such electrodes are discussed. An in-situ electrochemical pretreatment is proposed for activation and recovery of the activity of the carbon fibre electrode in flow-stream detection. The desirable detector was found to be nearly flow-rate independent. Catecholamines can be detected at concentrations as low as 2 × 10⁻⁹ M. The cell could be used in the mobile phase with little electrolyte. It was found that the solution resistance in the flow pathway was the major source of distortion of the shape of hydrodynamic voltammograms and of high noise at dilute electrolyte. Parallel detection using dual working electrodes is demonstrated for reversed-phase chromatographic separation of catecholamines.     

硫酸介质中Pb电极氧化物成长过程的研究

采用实时交流阻抗测量与激光扫描微区光电流技术相结合的现场方法,对铅电极在硫酸溶液中ＰｂＯ和ＰｂＯ＿２的生长过程进行了研究．发现电极在ＰｂＯ的形成区中氧化５ｍｉｎ后,电极欧姆阻抗和ｔ￣（１／２）呈一直线关系,这表明ＰｂＯ是均匀分布在电极表面而成长的．激光扫描微区光电流的实验进一步证实了这一结论．实验中还发现ＰｂＯ＿２在ＰｂＯ层中是局部发生与发展的．     

直立式光透金网电极薄层红外光谱电化学池的新设计

本文报告一种新式的光透式金网电极薄层红外光谱电化学池设计, 该设计使用聚甲氟乙烯池内盐桥/边际限制器, 连接直立式玻璃池体与氯化钠红外薄层池,设置薄层的池的电位参比点, 既便于监控操作, 又能得到良好的光谱电化学响应, 以二茂铁在二氯甲烷中的行为进行了表征。     

J-integral evaluation of nanoclay-modified HDPE/PA6 microfibrillar composites

Microfibrillar composites (MFC) are polymer-polymer composites with many advantages, including good dispersion and bonding of in-situ generated fibrils. Recently, it has been shown that their performance can be enhanced by suitable addition of organophilized montmorillonite (oMMT) provided the numerous oMMT-induced effects are harmonized. This work deals with evaluation of resistance against unstable crack propagation (J-integral) in combination with Charpy and tensile impact strength methods, and SEM observation of fibrils shape and size and fracture surfaces. The results indicate that addition of PA6 inclusions and oMMT to relatively ductile HDPE reduces toughness evaluated using Charpy and J-integral. The fact that tensile impact strength is not reduced by oMMT indicates the importance of the impact testing mode for MFC. Of importance is the fact that formation of PA6 fibres reinforced with oMMT practically does not reduce toughness. Hence, the drawn oMMT-modified system with significantly higher stiffness and practically unchanged fracture resistance can be obtained. Combination of the complex effect of oMMT and in-situ fibrils reinforcement present a tool to attain polymer systems with enhanced well-balanced properties.     

PREPARATION OF POLYSULFONAMIDE AND MODIFIED TITANIUM OXIDE NANOCOMPOSITES BY IN-SITU POLYMERIZATION

A kind of new nano composite with ultraviolet (UV) ray resistance and high temperature stability was prepared by in-situ polymerization in low temperature. Polysulfonamide (PSA) was synthesized with 4, 4'-diaminodiphenyl sulfone (DDS) and terephthaloyl chloride (TPC) in the common solvent N, N-Dimethyl- -acetamide (DMAc). Nano filler is a certain nano titanium oxide modified by silicon oxide (TMS), which plays the role of UV resistance additives. Properties of the novel composite materials were characterized by Atomic Force microscopy (AFM), thermal gravimetric Analysis (TGA) and Ultraviolet Spectroscopy. AFM had showed the sizes and distributions of TMS particles in the nanocomposite. Ultraviolet Spectroscopy for the nanocomposites showed a large absorption in UV band. TGA showed the decomposition temperature was increased over ten degrees with 0.5% wt TMS for this nanocomposite compared with pure PSA.