PTC特性的复合导电体系中炭粒子分布的逾渗模型与电阻率的计算

综述了炭黑填充型导电高分子复合体系的几种导电理论；讨论了导电载流子分布的各种假说及模型；比较了不同模型的理论预测与实验结果的差异性。     

LaB6-ZrB2共晶复合材料的组织特征及控制

用电弧炉和电子束悬浮区熔炉法制备了ＬａＢ６ＺｒＢ２共晶复合材料，并用ＳＥＭ和ＴＥＭ方法对其显微组织进行了研究。结果表明，ＬａＢ６ＺｒＢ２形成纤维状共晶组织，控制凝固条件可得到定向排列的组织，ＬａＢ６基体上均匀分布着直径为０２～１２μｍ的ＺｒＢ２纤维，纤维长度可达１００μｍ以上。对于固液界面为平面生长的试样，其结晶学取向关系为［００１］ＬａＢ６∥［００１］ＺｒＢ２，（１１０）ＬａＢ６∥（０１０）ＺｒＢ２。     

Response of protonic acid‐doped poly(o‐anisidine)/poly(vinyl alcohol) composites to relative humidity and role of dopant anions

Various protonated poly(o‐anisidine) (PoAN)/poly(vinyl alcohol) (PVA) composites were prepared with different types of acids: sulfuric (SA), p‐toluene sulfonic (TSA), camphor sulfonic (CSA), and p‐dodecylbenzene sulfonic (DBSA). In the visible spectrum of each composite in dimethyl sulfoxide, three absorption peaks were observed at 440, 620, and 860 nm. The peaks at 440 and 860 nm, which were enhanced with the increasing content of acid‐doped PoAN in the PVA matrix, were attributed to the radical cation and localized polaron generated in the conducting polymer. However, the peak at 620 nm was ascribed to the emeraldine base (EB) form of PoAN; that is, a portion of the acid was detached from the conducting polymer to form EB‐PoAN and free acid. The linear dependence of the logarithmic electrical conductivity on the variation of humidity, which was observed for all the composites, was caused by the salt–base transition of the conducting polymer, that is, by the movement of free acid between the active sites of the conducting polymer and the strongly bound water existing in PVA, which in turn depended directly on the environmental humidity. The response time of the composites to humidity was shortened with a decrease in the size of the dopant anions: DBSA > CSA > TSA > SA. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4343–4352, 2000     

New and novel organic-inorganic type crystalline ‘polypyrrolel/polyantimonic acid’ composite system: preparation, characterization and analytical applications as a cation-exchange material and Hg(II) ion-selective membrane electrode

A new phase of ‘organic-inorganic’ composite system, polypyrrole polyantimonic acid, prepared by mixing the inorganic precipitate of hydrated antimony oxide with organic conducting polymer i.e., polypyrrole, providing a novel granular form hybrid cation-exchanger suitable for column operation with better chemical and thermal stability, good ion-exchange capacity, reproducibility and selectivity for heavy metals. The physicochemical properties of this material were studied using elemental analyses, AAS, SEM, XRD, FTIR and simultaneous TGA-DTA studies. Ion-exchange capacity, pH-titrations, elution and distribution behavior were also carried out to characterize the material. Distribution studies revealed the cation-exchange material to be highly selective for Hg(II) and its selectivity was performed by achieving some important binary separations like Hg²⁺-Zn²⁺, Hg²⁺-Ni²⁺, Hg²⁺-Cu²⁺, Hg²⁺-Fe³⁺, Hg²⁺-Cd²⁺, Hg²⁺-Mg²⁺ etc. on its column. Using this electroactive composite material, a new heterogeneous precipitate based selective ion-sensitive membrane electrode was fabricated for the determination of Hg(II) ions in solutions. The membrane electrode is mechanically stable, with a quick response time, and can be operated within a wide pH range. The selectivity coefficients for different cations determined by mixed solution method were found to be less than unity The electrode was also found to be satisfactory in electrometric titrations.     

Confined Crystallization of Spin‐Crossover Nanoparticles in Block‐Copolymer Micelles

Nanoparticles of the spin‐crossover coordination polymer [FeL(bipy)]_n were synthesized by confined crystallization within the core of polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) diblock copolymer micelles. The 4VP units in the micellar core act as coordination sites for the Fe complex. In the bulk material, the spin‐crossover nanoparticles in the core are well isolated from each other allowing thermal treatment without disintegration of their structure. During annealing above the glass transition temperature of the PS block, the transition temperature is shifted gradually to higher temperatures from the as‐synthesized product (T_1/2↓=163 K and T_1/2↑=170 K) to the annealed product (T_1/2↓=203 K and T_1/2↑=217 K) along with an increase in hysteresis width from 6 K to 14 K. Thus, the spin‐crossover properties can be shifted towards the properties of the related bulk material. The stability of the nanocomposite allows further processing, such as electrospinning from solution.     

Enhanced Surface Interactions Enable Fast Li+ Conduction in Oxide/Polymer Composite Electrolyte

Li⁺‐conducting oxides are considered better ceramic fillers than Li⁺‐insulating oxides for improving Li⁺ conductivity in composite polymer electrolytes owing to their ability to conduct Li⁺ through the ceramic oxide as well as across the oxide/polymer interface. Here we use two Li⁺‐insulating oxides (fluorite Gd_0.1Ce_0.9O_1.95 and perovskite La_0.8Sr_0.2Ga_0.8Mg_0.2O_2.55) with a high concentration of oxygen vacancies to demonstrate two oxide/poly(ethylene oxide) (PEO)‐based polymer composite electrolytes, each with a Li⁺ conductivity above 10^?4 S cm^?1 at 30 °C. Li solid‐state NMR results show an increase in Li⁺ ions (>10 %) occupying the more mobile A2 environment in the composite electrolytes. This increase in A2‐site occupancy originates from the strong interaction between the O^2? of Li‐salt anion and the surface oxygen vacancies of each oxide and contributes to the more facile Li⁺ transport. All‐solid‐state Li‐metal cells with these composite electrolytes demonstrate a small interfacial resistance with good cycling performance at 35 °C.     

Functionalized Cellulose Based Microcomposites

Summary: A technique has been developed that allows the production of cellulosic micro composites by immobilizing super-ground functionalised materials in the cellulose matrix. For this purpose, the well-established ALCERU® process has been a subject of technological modification. Depending on the degree of filling, several types of composites are accessible. At lower concentrations, the fibres maintain their textile-physical parameters and may be used in applications, where a textile appearance is required. The increasing concentration of the functional additives influences increasingly the overall properties of the composite and leads to composites with special functions such as water retention, electric conductivity, and specific absorption ability for organics or heat storage functions. In addition, loads exceeding the cellulose portion are useful as green shapes for ceramics.     

纳米复合氧化物催化发光法测定空气中的甲醛

基于纳米复合氧化物上甲醛被催化氧化产生化学发光的现象, 建立了直接测定空气中微量甲醛的方法. 实验发现, 甲醛在许多纳米级金属氧化物表面都有发光现象, 但在纳米级钼钒钛(原子比为2∶3∶5)复合氧化物表面上有较高的发光强度和较好的选择性. 最佳实验条件为: 分析波长535 nm, 测定温度265 ℃, 载气流速150 mL/min. 方法的检测限(3σ)为0.04 mg/m³, 线性范围为0.07～34 mg/m³, 相关系数为0.9994, 回收率为98.2%～101.4%. 对常见共存物的研究发现, 除丙酮外, 苯、氨、二氧化硫和乙醇不干扰测定.     

Ni／ZrO2-Al2O3制备表征及催化性能的研究

本文采用浸渍沉淀法制备了不同配比的ZrO2-Al2O3复合载体。并通过浸渍法制备Ni/ZrO2-Al2O3催化剂,以苯加氢制环己烷反应为探针,考察了ZrO2与Al2O3的配比对Ni催化剂催化加氢性能的影响;采用X射线衍射(XRD)、程序升温还原(TPR)、程序升温脱附(TPD)等技术考察复合载体对Ni催化剂的体相结构、还原性能以及表面吸附性能的影响。研究结果表明,ZrO2质量分数为20%的复合载体所负载的Ni催化剂有很好的加氢活性,优于单组分载体负载的Ni催化剂;采用浸渍沉淀法制备的ZrO2-Al2O3复合载体中ZrO2以非晶态形式存在,这是由于Al2O3的存在影响了ZrO2的内部结构;该载体负载的Ni催化剂较其他催化剂更容易被还原,吸附中心数量增加。     

基于聚硫堇、DNA/纳米银复合物共修饰癌胚抗原免疫传感器的研究

将硫堇聚合到玻碳电极(GCE)表面形成带正电的多孔聚硫堇(PTH)复合膜, 通过静电吸附固定DNA/纳米银复合物, 利用复合物中纳米银大的比表面积和强的吸附能力将癌胚抗体(anti-CEA)固定到电极表面, 从而制得高灵敏的电流型癌胚抗原(CEA)免疫传感器. 通过循环伏安法考察了电极表面的电化学行为, 并对免疫传感器的性能进行了详细研究. 在最优的实验条件下, 用示差脉冲伏安法(DPV)对癌胚抗原进行检测, 其线性范围为1.0～10.0 ng•mL^－1和10.0～80.0 ng•mL^－1, 线性相关系数分别为0.9983和0.9970, 检测限为0.24 ng•mL^－1, 并将该免疫传感器用于血清样品中CEA的检测.