纳米聚苯胺的合成及其性能表征

采用微乳液法制得了纳米聚苯胺,并讨论了乳化剂、氧化剂的用量对聚苯胺粒子的粒径、电导率、分子链结构等的影响.     

纳米聚苯胺的合成及其性能表征

采用微乳液法制得了纳米聚苯胺,并讨论了乳化剂、氧化剂的用量对聚苯胺粒子的粒径、电导率、分子链结构等的影响。     

纳米聚苯胺的合成及其性能表征

采用微乳液法制得了纳米聚苯胺,并讨论了乳化剂、氧化剂的用量对聚苯胺粒子的粒径、电导率、分子链结构等的影响。     

纳米碳管掺杂聚苯胺的光电性能

用三种方法制作了的掺杂聚苯胺,通过对材料光学、电阻、电磁参数及电磁屏蔽等特性的研究,结果表明掺杂提高了材料的电性能,但降低了其光学性能.     

导电聚苯胺纳米粒子的形成及影响因素

系统论述了导电聚苯胺纳米粒子的形成过程、影响因素、粒径、形貌和应用。指出苯胺单体呈取向排列,聚合反应主要发生在油水两相界面处;生成的粒子受合成方法、水乳比、聚合介质、超声作用等因素的影响,粒径在100nm以下,最小可达8nm,多为球形,也有针形和圆盘形;不同聚合方法得到的纳米粒子的电导率相差4-5个数量级。聚苯胺纳米粒子可以稳定地分散于聚合体系中,大大克服了聚苯胺难溶难熔的固有缺点。导电纳米聚苯胺共混复合材料具有极低的逾渗域值,最低可达0．03％。可望应用于透明导电膜、塑料薄膜抗静电、防腐涂料、纳米复合材料等领域。     

导电聚合物聚苯胺的制备与表征及导电性能的研究

在实验中采用苯胺在不同的酸性介质中,用过硫酸铵氧化聚合得到聚苯胺,发现其反应产率和聚苯胺的电导率都存在着较大的差异,并且发现酸的强度和氧化能力对聚苯胺的聚合有着较大的影响,并对聚苯胺进行了红外光谱和紫外可见光光谱分析与表征,表明聚苯胺主链结构经质子酸掺杂后由于电子的离域形成了共轭结构,从而使聚苯胺有良好的导电性能。     

导电聚苯胺/OMMT纳米复合材料的研究

以十二烷基苯磺酸(DBSA)为掺杂剂和乳化剂,过硫酸铵(APS)为引发剂,采用乳液插层聚合方法制备了导电聚苯胺包覆有机蒙脱土(OMMT)纳米复合材料。探讨OMMT、APS和DBSA用量对复合材料电导率的影响。结果表明,在苯胺、APS、DBSA三者摩尔比为1：1：1．5时,苯胺与OMMT质量比为1：3.5时,复合材料的电寻率最高可达0．0571S／cm。用X射线衍射和傅立叶变换红外光谱对复合材料进行了表征。结果表明,聚苯胺已插层到OMMT层间,且聚苯胺在受限的纳米空间只能以有限层分子存在,很可能是伸展链构象。     

聚苯胺/镍纳米复合材料的制备及其表征

以苯胺（An）、氯化镍（NiCl2×6H2O）为原料,原位聚合法合成聚苯胺/镍纳米复合微粒。采用X射线衍射仪、扫描电镜、傅里叶变换红外光谱仪、振动样品磁强计（VSM）及四探针测试仪技术表征了复合微粒的结构、形貌和电磁性能。结果表明：复合微粒在室温外加磁场下表现出铁磁性物质具有的磁滞现象,饱和磁化强度为9.44 emu/g,复合微粒在室温下的电导率为5×10-3 S/cm。     

镨掺杂的聚苯胺及其性能的研究

以苯胺、硝酸镨合成了本征态聚苯胺和掺杂态聚苯胺.采用扫描电镜、导电测试仪、红外光谱、TGA和XRD等对产物进行表征.结果表明硝酸镨很好地掺杂于聚苯胺基体内,当硝酸错与苯胺的摩尔比为1:1.5时,产物的电导率较好,为0.015 5 S/cm.     

十二烷基苯磺酸掺杂聚苯胺的性能研究

用十二烷基苯磺酸 (DBSA)对本征态聚苯胺 (PAn)进行掺杂 ,得到溶解性、成膜性和光电性能俱佳的掺杂态聚苯胺。红外光谱研究表明 :DBSA掺杂PAn的吸收峰都向低频方向移动。探讨DBSA浓度、掺杂温度和时间以及洗涤滤液pH值对聚苯胺电导率的影响。结果表明 :当c(DBSA) =1 0mol/L ,T =32 3K ,t=8h ,洗涤滤液 pH =3时 ,聚苯胺的电导率为 0 90 9S/cm。紫外 -可见吸收光谱表明 ,掺杂态聚苯胺的吸收峰变宽而且发生红移。X射线衍射在 2θ =8 86°,1 7 7° ,2 1 4°和 2 6 7°处出现 4个较强的低角度衍射峰 ,表明DBSA掺杂的聚苯胺具有较强的结晶性能。     

易分散纳米聚苯胺改性环氧铁红底漆的防腐性研究

通过引入表面活性剂,合成了易分散纳米聚苯胺(PANI-1)。运用傅里叶变换红外光谱仪(FTIR)和场发射扫描电镜(FE-SEM)表征了聚苯胺的结构,利用电化学方法研究了聚苯胺的防腐性,并采用聚苯胺对环氧铁红底漆进行改性。研究发现,经过表面活性剂改性的聚苯胺为松散纳米结构,容易分散于有机溶剂中;腐蚀测试结果表明,聚苯胺对碳钢有较好的防腐蚀能力,当PANI-1含量为3.5%时,纳米聚苯胺改性环氧铁红底漆涂层具有较好的防腐蚀能力,可应用于桥梁、道路护栏等钢结构的防腐工程。     

Application of XPS to coal characterization

The use of X-ray photoelectron spectroscopy to probe the chemistry of coal surfaces is reviewed and its application to the functional group composition of bulk coals is discussed. The surface composition of a range of 19 coals (anthracite to brown coal), ground under heptane, was measured and compared with the results of bulk analysis. A good correlation was obtained for oxygen, with the bituminous and higher-rank coals showing surface enrichment in oxygen. The surface bulk correlation was less good for sulphur, nitrogen and chlorine and was poor for silicon, aluminium and iron. Silicon and aluminium are enriched at the surface while iron is surface deplected. These effects are either due to different particlesize distributions of the mineral and organic phases or to the mechanism of fracture in heptane preferentially exposing specific components of the coal. Oxidation and carbonization of a bituminous coal were also investigated. Oxidation was seen to occur initially via the exterior surface, producing a distribution of carbon—oxygen groups. Singly-bonded species predominate at all temperatures, stable carboxyl groups forming in significant proportions only at temperatures > 250 °C. Carbonization was seen to result in the formation of ether linkages by condensation of hydroxyl groups.     

XPS在稀土配合物结构研究中的应用

本文以两类稀土配位化合物为例 ,以 XPS测得的其结合能数据为依据 ,通过详细地分析和讨论这些结合能数据与原子周围价电荷分布和运动的关系 ,阐明了这两类化合物的电子结构和化学键的性质     

XPS study of pyrite-free coals subjected to different oxidizing agents

Surface composition of two of pyrite-free coals characterized by a high organic sulphur content subjected to oxidation by peroxyacetic acid, oxygen in 0.5 N Na₂CO₃ aqueous solution and air for 7 days at 125 °C were studied. Oxidation process followed the route: diffusion → chemisorption (formation of oxidized surface species) → further oxidation of surface species → gasification. The extent of each stage was dependent on the structure of initial coal. PAA acid was found to be the most efficient oxidizing and desulphurizing agent. The role of pyrite was discussed. The removal of pyrite influenced the results of the oxidation process following it. The oxidation ability of the used media formed a similar sequence (PAA > O₂/Na₂CO₃ > air/125) for coal samples with or without FeS₂, but the numerical values of several parameters (the surface content of elements C, O, S, N; the type and number of oxygen-or sulphur-containing surface species) differed in both cases. The presence of FeS₂ increased oxidation rate but the overall effect depended on the starting amount of oxygen-containing surface species which in turn was influenced by the procedure of pyrite removal.     

XPS analysis of fluorinated polyimides

Five different fluorinated polyimides were characterized using X-ray photoelectron spectroscopy (XPS). Elemental compositions and polyimide stoichiometries as elucidated with XPS are reported. The fluorinated polyimides derived from corresponding poly(amic acid)s were completely imidized after thermal cure at 350°C, giving rise to a single N 1s peak at 400.8 eV. Interestingly, fluorine segregation on the cured polyimide surface was found to be a function of the polyimide backbone stiffness.     

The Definition of the Locus of Failure on Ceramic Substrates: The Benefit of Monochromated XPS

The use of X-ray photoelectron spectroscopy (XPS) to assess the locus of failure of a photo-cured resin on an alumina substrate is reported. It is shown that the carbon 1s spectra obtained with conventional (achromatic) and monochromatic photon sources are markedly different. The spectrum obtained with the monochromatic source reveals the fine structure associated with the polymer whilst the spectrum recorded with the conventional source is distorted by differential charging. This observation has important ramifications when XPS is used for the definition of the locus of failure of organic coatings, or adhesives, applied to insulating substrates such as ceramics.     

FT-IR and XPS studies of polyurethane-urea-imide coatings

A series of polyurethane (PU)-urea-imide coatings were synthesized by a systematic three-step reaction process. Initially isocyanate terminated PU prepolymers were prepared by reacting soft segments such as polyester polyols (prepared from neopentyl glycol, adipic acid, isophathalic acid and trimethylol propane) or polyether polyols (polypropylene glycol-1000) with hard segments such as 2,4-toluene diisocyanate or isophorone diisocyanate with NCO/OH ratio of 2:1. Heterocyclic imide ring into the PU backbone was incorporated by co-polymerization with pyromellitic dianhydride (PMDA) from the excess NCO groups in the PU prepolymer with an NCO/anhydride ratio of 1:0.5 and the surplus NCO content after imidization was moisture cured. PU-urea-imide coatings were also obtained by partial chain extension of the excess NCO groups in the NCO terminated PU-imide copolymers, and the remaining excess NCO groups were completely reacted with atmospheric moisture. The obtained polymers were analyzed with Fourier transform-infrared (FT-IR) and angle resolved X-ray photoelectron spectroscopy (AR-XPS). The type and change in intermolecular H-bonding interaction in the PU-urea-imide films with structural variables was identified by deconvolution of the FT-IR spectra using Origin 6.0 software through Gaussian curve-fitting method. The FT-IR analyses of the PU-urea-imide coating films show dependence of phase separation on the nature of chain extender. Surface characterization data from AR-XPS suggests the dependence of phase segregation behaviour on the nature of the chain extender, which also supports the FT-IR observations.     

Acidity of heteropoly compounds from XPS measurements

The changes in the partial charges on oxygens in the various heteropoly salts as a result of the acidity differences have been exploited for probing the oxygen 1s and W 4f lines. The gradation of the acidity thus obtained is compared to that of the conventional method.     

TiBCN高温陶瓷的XPS分析

本文采用放电等离子烧结法在1700°C、1800°C及1900°C下制备了TiBCN陶瓷,并采用XPS对所制备的TiBCN材料表面组成及元素存在状态进行了详细的分析研究。实验结果表明,不同温度下,钛(Ti)、硼(B)、碳(C)、氮(N)等各元素的存在形式显著不同。1800°C烧结的TiBCN材料主要由高熔点高硬度的TiB_2、TiN和TiBCN三种晶相构成。