热处理对聚四氟乙烯-聚苯胺系列导电复合膜性能的影响

对电化学制备的聚四氟乙烯-聚苯胺系列导电复合膜进行热处理,采用热重、红外和X衍射等手段研究了在空气和真空氛围中,热处理对复合膜的电导率及力学性能的影响。热分析结果表明：此系列复合膜在100～180°C失重较少,在此温度区间内对聚苯胺-聚四氟乙烯复合膜热处理,其电导率在空气和真空氛围中均随热处理温度升高而下降,聚苯胺-聚四氟乙烯-银复合膜在空气氛围中的电导率也随热处理温度升高而下降,两种复合膜的强度不变,断裂伸长率降低;聚苯胺-聚四氟乙烯-银复合膜在真空氛围中经120°C热处理后电导率提高最显著,力学强度也有所提高,但断裂伸长率降低。X衍射研究表明复合膜经180°C热处理后结晶度降低。红外分析结果表明聚苯胺-聚四氟乙烯复合膜经180°C热处理,发生了磺基水杨酸的脱掺杂和聚苯胺的结构热氧化、分子链的断裂和交联,复合膜电导率降低。     

盐酸掺杂制备导电性聚苯胺的工艺优化研究

掺杂是获得高导电性聚苯胺的重要手段.本文采用盐酸进行掺杂,通过实验研究了不同条件下盐酸掺杂对聚苯胺基本性能的影响,优化了制备聚苯胺的工艺条件.当过硫酸铵与苯胺比为1时,聚合产率高达66.14%;当盐酸浓度为1.5mol/L时,室温下反应12h导电性最好.制备了聚苯胺样品,并对样品进行了FT-IR、SEM、XRD测试.结果均表明盐酸掺杂聚苯胺的反应主要发生在醌环上,掺杂后聚苯胺有一定的结晶性,且呈微纳米颗粒状、分布均匀,电导率达到1.29S·cm~(-1).正交试验得出的优化工艺为:盐酸浓度为1.0mol·L~(-1),氧化剂与苯胺单体摩尔比为1∶1,室温条件下反应4h.     

盐酸和磺基水杨酸复合掺杂聚苯胺的热电性能

以苯胺为单体,过硫酸铵为氧化剂,采用化学氧化聚合法在盐酸和磺基水杨酸混合溶液中制备了导电聚苯胺。通过XRD、SEM、FTIR等分析手段,对所得产物的结构进行研究,并探讨在相同聚合条件下,不同的磺基水杨酸和盐酸的物质的量浓度比(cSSA∶cHCl)对聚苯胺热电性能的影响。结果显示,混合酸掺杂聚苯胺的电导率随cSSA∶cHCl的增加而增大,但Seebeck系数的变化趋势却与之相反。当cSSA∶cHCl=0.25:1时,掺杂态聚苯胺的功率因子在175℃时达到最大值为0.46μW.m-1.K-2,分别是相同条件下HCl和SSA掺杂聚苯胺的1.7和1.9倍。这表明适当配比的有机酸与无机酸混合掺杂比单一酸掺杂更有利于聚苯胺热电性能的提高。     

复合酸掺杂导电聚苯胺的合成及性能

采用复合酸掺杂微乳液法合成导电聚苯胺. 探讨了反应温度和掺杂剂质量比对聚苯胺性能的影响,并通过四探针、塔菲尔曲线、激光粒度分析、热重分析以及红外光谱测试技术,对聚苯胺进行了研究与表征. 结果表明,当聚合温度为15 ℃、磺基水杨酸和十二烷基苯磺酸钠的质量比为2.5∶1时,掺杂态聚苯胺电导率和溶解度达到最大值,同时具有良好的防腐蚀能力;其中电导率可达11 S/cm,在氮甲基吡咯烷酮(NMP)中溶解度可达85%;经电化学工作站测试的塔菲尔曲线可知,其腐蚀电位为-0.391 V. 热重分析表明,复合酸掺杂聚苯胺热分解温度约为440 ℃;粒径分析表明,约有90%的聚苯胺颗粒集中在50～100 nm之间.红外光谱表明,复合酸掺杂聚苯胺各主要吸收峰均向低频方向移动,说明掺杂的有效性.     

聚（3—丁基噻吩）电导的热稳定性

研究了导电聚合物聚（３－丁基噻吩）（ＰＢＴ）在大气环境下的导电热稳定性。在室温至２２０℃范围内，测试电导率随时间及温度的变化。ＴＧＡ分析以及化学分析的结果表明：掺杂态的ＰＢＴ大约在１４０℃附近有一转化温度，低于或高于这一转化温度，电导率下降的决定因素各不相同。高于转化温度时，电导率下降的主要原因是反离子和高分子主链的解离，进而发生化学反应，影响了高分子主链的结构。ＸＰＳ测试结果表明：经热处理后的Ｐ     

反应温度对衣康酸掺杂聚苯胺性能的影响

以衣康酸为掺杂剂,过硫酸铵为引发剂,采用化学氧化聚合法在不同的反应温度下合成聚苯胺(PANI)。计算其产率和电导率,并测定掺杂态聚苯胺的各项性能指标。通过电阻测试、傅立叶红外光谱测试(FT-IR)、紫外-可见光谱测试(UV-vis)、电子探针分别对产物的导电性、化学结构、紫外可见光谱和微观形貌进行了表征。结果表明,低温有利于减缓链终止的速度使得产物分子链较长,从而使载流子的传输更容易进行,产物电导率高;而温度高于10℃会使聚苯胺氧化断链,使产物电导率下降。以反应温度为10℃时电导率最高,为1.29×10-2(S·cm-1),且具有最高的产率为111.2%,微观形貌为纳米棒状结构。     

聚苯胺薄膜的离子束效应

本文采用离子注入掺杂技术，研究了全氧化态聚苯胺薄膜的离子束效应．‘４０ｋＶＫ＋离子束注入后，聚苯胺薄膜的电导率随着剂量的增加而迅速增加．当剂量为１×１０１７Ｋ＋／ｃｍ２时，电导率增加了８个数量级．ＦＴＩＲ光谱图显示了Ｋ＋离子注入使全氧化态聚苯胺中的醌亚胺结构发生还原反应．温差电流法测量表明，离子注入区呈现ｎ型半导体特性．四探针法测量了离子注入掺杂聚苯胺的电导率与温度的关系．本文还对离子注入掺杂全氧化态聚苯胺的导电机制进行了初步探讨．     

聚苯胺的电荷传输特性及其分子量依赖性

研究了樟脑磺酸掺杂的聚苯胺 (PAn CSA)膜的导电性对温度的依赖性 ,发现有一个临界温度 (Tc) ,当测试温度高于Tc 时 ,PAn CSA显示金属的导电特性 ,反之则显示半导体导电特性 .Tc 和聚苯胺的分子量有关 ,分子量越高 ,Tc 越低 .单向拉伸后 ,PAn CSA膜的电导率大大提高 ,拉伸 6 0 %时 ,室温电导率可达 75 0S/cm ,但Tc 不随拉伸而变化     

掺杂条件对聚苯胺膜导电性能影响的研究

采用对甲基苯磺酸和磺基水杨酸作掺杂剂，对聚苯胺自支撑膜进行了掺杂研究，考查了掺杂时间，温度以及掺杂溶液浓度对其导电性的影响，并用红外光谱及显色反应对掺杂产物进行了表征。结果表明，掺杂温度对聚苯胺膜电导率的影响较大，通过控制温度，可以制备出电导率达盐酸掺杂水平的导电膜，即－１０＾３Ｓ．ｍ＾－１，且具有良好的环境稳定性，在空气中放置一年，其电导率基本保持不变。     

聚苯胺水基胶体分散液及其复合物的研究 Ⅱ紫外光谱及导电性能

利用紫外可见光谱研究了聚苯胺（ＰＡｎ）在水基胶体分散液中掺杂与脱掺杂过程，证实了ＰＡｎ的掺杂与脱掺杂是完全可逆的过程．当ｐＨ＝３５时，开始脱掺杂，当ｐＨ＝６０时，脱掺杂已基本结束．ＰＡｎ颗粒的大小也对紫外光谱有影响．当聚苯胺颗粒尺寸达到纳米量级时（１００ｎｍ），复合膜光谱吸收峰明显兰移，表现出了表面效应和量子尺寸效应．聚苯胺／聚乙烯醇复合膜的电导率不仅受聚苯胺含量的影响，同时也受复合膜中聚苯胺颗粒聚集状态的影响．较小的聚苯胺颗粒，使复合膜具有较低的渗滤阈值．     

Kinetics of thermal decomposition of nickel sulfate hexahydrate

The paper describes the kinetics of all the recorded steps of thermal decomposition of nickel sulfate hexahydrate in air. The thermal decomposition of the salt in air led to NiO at about 1060 K. The kinetic parameters, the activation energyE and the preexponential factorA, and the thermodynamic parameters, the entropy, enthalpy and free energy of activation were evaluated for the dehydration and decomposition reactions. Tentative reaction mechanisms are suggested for each step of the thermal decomposition.     

Development of a thermal conductivity cell with nanolayer coating for thermal conductivity measurement of fluids

Various techniques and methodologies of thermal conductivity measurement have been based on the determination of the rate of directional heat flow through a material having a unit temperature differential between its opposing faces. The constancy of the rate depends on the material density, its thermal resistance and the heat flow path itself. The last of these variables contributes most significantly to the true value of steady-state axial and radial heat dissipation depending on the magnitude of transient thermal diffusivity along these directions. The transient hot-wire technique is broadly used for absolute measurements of the thermal conductivity of fluids. Refinement of this method has resulted in a capability for accurate and simultaneous measurement of both thermal conductivity and thermal diffusivity together with the determination of the specific heat. However, these measurements, especially those for the thermal diffusivity, may be significantly influenced by fluid radiation. Recently developed corrections have been used to examine this assumption and rectify the influence of even weak fluid radiation. A thermal conductivity cell for measurement of the thermal properties of electrically conducting fluids has been developed and discussed.     

Thermal Behaviour of Pharmacologically Active Lithium Compounds

The thermal decompositions of a series of simple lithium compounds (carbonate, sulfate, acetate, citrates, aspartates and glutamates) currently used in the treatment of manic-depressive psychosis and related disorders were investigated by means of TG and DTA measurements in oxygen atmosphere. Pyrolysis residues were characterized by infrared spectroscopy. The stabilities of the hydrates and intermediate phases generated during the degradation processes are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal Analysis in Studies of Technological Waste Materials to Be Subjected to Thermal Treatment

Attempt was made to evaluate the usefulness of thermoanalytical methods, combined with X-ray phase analysis and chemical analyses, for the study of thermal decomposition of waste materials to be subjected to thermal treatment. The object of the studies were petrochemical waste materials intended to be decomposed in a rotary furnace. Results are given of the studies of five selected waste materials. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal Properties of K（Y1-xYbx）（WO4）2（x=0.098,0.196,0.294） Crystal

Thermal properties of pure KY(WO4)2 and K(Y1-xYbx)(WO4)2(x=0.098,0.196,0.294) crystals were investigated.The specific heat and thermal diffusivity of crystals were calculated at a range of 50～300 ℃.The calculated result shows that the specific heat and thermal diffusivity of K(Y1-xYbx)(WO4)2(x=0.098,0.196,0.294) crystals were slightly affected by the Yb3+ concentration.The thermal expansion coefficient of K(Y0.804Yb0.196)(WO4)2 crystals along x,y and z axes were determined to be 13.51,4.474 and 16.60×10-6 K-1,respectively.These results suggest the K(Y1-xYbx)(WO4)2(x=0.098,0.196,0.294) crystal as a laser crystal of low-middle power.     

Parameter determination of a thermal desorption model

A new method for the analysis of thermal desorption spectra is presented, based on the experimental peak maximum functions for temperatureT _m(β) and pressureP _m(β) and a rigorous mathematical treatment. The resonant heating rate β_r is determined, satisfyingT _m(β_r)=T _r, whereT _r is the resonant temperature defined byA exp(−E _d/(RT _r))=1. Desorption energyE _d and frequency factorA can be determined simultaneously with relatively high robustness towards statistical experimental errors as demonstrated by computer-simulated thermal desorption spectra.     

Photoacoustic infrared spectroscopy and thermophysical properties of syncrude cokes

This paper presents and interprets photoacoustic (PA) infrared spectra and four different thermophysical properties (thermal conductivity, thermal diffusivity, volumetric specific heat and thermal effusivity) for four sets of hydrocarbon cokes. A total of 12 samples, with varying histories, were analyzed. These cokes are a by-product of the upgrading of bitumen to Syncrude Sweet Blend (a blend of hydrotreated components), and were obtained from several locations in the thermal cokers operated by Syncrude Canada Ltd. in Fort McMurray, Alberta, Canada. PA infrared spectroscopy provides detailed information on the amount and type of residual aromatic hydrocarbons in cokes; aliphatic hydrocarbons are sometimes detected in smaller quantities. Three of the thermophysical properties (thermal conductivity, diffusivity and effusivity) display systematic differences among the cokes. On the other hand, volumetric specific heat hardly varies, a phenomenon that accounts for the observed proportionality between thermal diffusivity and conductivity. Analogous relationships exist between thermal effusivity and both thermal conductivity and thermal diffusivity for these cokes. The magnitudes of these three thermophysical properties tend to increase as aromatics contents, determined by PA spectroscopy, decrease.This revised version was published online in November 2005 with corrections to the Cover Date.     

Effects of vapor‐phase‐formaldehyde treatments on thermal conductivity and diffusivity of ramie fibers in the range of low temperature

To understand the influence to thermal conductivity by bridging in the polymer fibers, the thermal conductivity, and thermal diffusivity of ramie fiber and those bridged by formaldehyde (HCHO) using vapor‐phase method (VP‐HCHO treatment) were investigated in the lower temperature range. The thermal conductivities of ramie fiber with and without VP‐HCHO treatments decreased with decreasing temperature. Thermal diffusivities of ramie fiber with and without VP‐HCHO treatments were almost constant in the temperature range of 250–50 K, and increased by decreasing temperature below 50 K. Thermal conductivity and thermal diffusivity of ramie fiber decreased by VP‐HCHO treatment. The crystallinities and orientation angles of ramie fibers with and without VP‐HCHO treatment were measured using solid state NMR and X‐ray diffraction. These were almost independent of VP‐HCHO treatment. Although tensile modulus decreased slightly by VP‐HCHO treatment, the decrease could not explain the decrease in thermal conductivity and diffusivity with decreasing sound velocity. The decrease of the thermal diffusivity and thermal conductivity by VP‐HCHO treatment suggested the possibility of the reduction of the mean free path of phonon by HCHO in VP‐HCHO treated ramie fiber. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2754–2766, 2005     

煤系高岭土热化学反应动力学

煤系高岭土的热化学反应包括高岭土的脱羟与反应与煤的燃烧反应。利用程序升温热分析法得到几种煤系高岭土样品的ＴＧ／ＤＴＧ谱图，由Ｆｒｅｅｍａｎ－Ｃａｒｒｏｌｌ法计算出煤系高岭土势化学反应的动力学参数。     

Application of Thermal Analysis in Radiocarbon Dating

Thermal analysis combined with mass spectrometry was applied to radiocarbon dating procedures (age determination of carbon containing samples) to determine the optimal temperature range for the reduction of CO₂ over metallic cobalt of various particle sizes. Experiments were carried out to show the different catalytic activities of cobalt of particle sizes 1, 1–45 and 44 μm. The morphology of the cobalt samples and the deposited carbon were investigated. The quantification of CH₄ and CO formed during the reduction of CO₂ was done by means of pulse thermal analysis. This revised version was published online in July 2006 with corrections to the Cover Date.