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油溶性LaF3纳米颗粒的制备及表征 总被引:2,自引:1,他引:1
以油酸镧和氟化钠为主要原料,在甲苯和水两相体系中制备了油酸镧表面修饰的LaF3纳米颗粒。并用透射电子显微镜、红外光谱仪、x-射线光电子能谱等现代分析手段对所得的LaF3纳米颗粒进行结构表征。结果表明,所制备的油酸镧修饰LaFs纳米颗粒大小均匀,粒径约为10nm,由于表薤修饰剂油酸镧与LaF3纳米颗粒表面之闻发生化学键合作甩,使得油酸镧修饰LaF3纳米颗粒在低极性有机溶剂中的分散性明显提高。 相似文献
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以乙酰丙酮铁和氯铂酸作为Fe源和Pt源,1,2-十二烷二醇为还原剂,通过多元醇还原法制备出单分散的FePt纳米颗粒,研究了表面活性剂油酸和油胺对FePt纳米颗粒形貌和分散性的影响。结果显示,未使用表面活性剂制得的FePt纳米颗粒粒度范围是1.0~6.0 nm,平均粒径为3.4 nm;使用油酸和油胺制得的FePt纳米颗粒粒度范围是2.5~5.5 nm,平均粒径4.1 nm。通过XRD、TEM和VSM分析表明,油酸和油胺修饰的FePt纳米颗粒为面心立方结构,形状近似球形,分散性良好,粒径分布较未使用表面活性剂时变窄;VSM显示其矫顽力趋近于0,呈现超顺磁性。 相似文献
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单分散纳米二氧化硅的制备与分散性研究 总被引:2,自引:0,他引:2
为得到单分散纳米二氧化硅颗粒,同时提高纳米二氧化硅颗粒在有机溶剂中的分散性。先采用改进工艺条件的溶胶-凝胶法制备纳米二氧化硅颗粒,研究了R\[R=c(H2O)/c(TEOS)\]、氨水浓度、TEOS(正硅酸乙酯)浓度、温度对纳米二氧化硅颗粒粒径的影响,采用TEM对颗粒形貌、粒径进行了表征。结果表明,随着R、氨水浓度和TEOS浓度的增大,二氧化硅粒径增大;随着反应温度的增加,二氧化硅粒径减小。用聚乙二醇和癸二酸缩聚得到的两亲性聚酯对自制的二氧化硅颗粒进行表面吸附改性。并用FT-IR、TG、TEM对改性前后的纳米二氧化硅的结构、分散性进行了表征。结果表明,改性后的纳米二氧化硅在甲苯中具有良好的分散性。 相似文献
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氢氧焰燃烧制备纳米Al2O3颗粒及其分散性能 总被引:2,自引:0,他引:2
利用多重射流氢氧燃烧反应器,以AlCl3为前驱体制备了具有不同形貌和晶型结构的Al2O3纳米颗粒,表征了其形貌、晶型结构、比表面积、粒径分布等性能,考察了火焰燃烧形式和反应区最高温度等因素对颗粒性能的影响规律. 结果表明,随反应温度升高,Al2O3粒径不断长大,形貌从具有链状结构的不规则颗粒逐渐转变为分散性良好的球形颗粒;同时随反应温度升高和在高温火焰中停留时间延长,晶型由单纯g相逐渐转变为d和d*相. 产品纳米Al2O3颗粒具有较强亲水性,其分散液具有较好的稳定性. 探讨了高温快速反应过程中颗粒和团聚体的生长机理,最终产物的粒径和团聚体形貌取决于各主要影响条件的相互竞争. 相似文献
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以次亚磷酸钠为还原剂,双烷氧基二硫代磷酸铵盐为修饰剂,在四氢呋喃-饱和食盐水的两相体系中合成了表面修饰的铁纳米颗粒,采用红外光谱仪、热分析仪等仪器对其进行了结构表征;在透射电子显微镜下观测所制备的铁纳米颗粒的形貌;在四球摩擦试验机上测试了其摩擦性能,并在扫描电子显微镜和能谱分析仪上对钢球表面进行了形貌观测和表层成分分析。结果表明,铁纳米颗粒在低极性有机溶剂中具有良好的分散性,并具有良好的抗磨和承载能力。磨斑的表面分析表明,铁纳米颗粒添加剂在边界润滑下形成了一层含Fe、S、P和O元素的表面膜是其具有良好摩擦学性能的主要原因。 相似文献
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以巯基乙酸(HSCH2COOH, RSH)为表面修饰剂,采用水相合成法制备了表面修饰巯基乙酸的ZnS纳米颗粒. 采用透射电子显微镜、粒度分布、X射线衍射和红外光谱等对ZnS纳米颗粒进行了表征,并对ZnS纳米粒子的制备条件进行了详细的考察. 结果表明,水相合成法的最佳制备条件为:反应pH值8.0, Zn2+:S2-:RSH(摩尔浓度比)为1:1.34:2. 在最佳条件下可制备粒径小(11 nm)且粒度分布窄、分散性好的ZnS纳米粒子,其晶体属面心立方b-闪锌矿结构. 相似文献
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采用多层修饰方法制备出精氨酸修饰的磁性纳米基因载体,对样品进行了粒度分析、Zeta电位分析、耐酸性能、生物相容性、体外细胞转染性能研究。结果显示,精氨酸修饰的磁性纳米颗粒均匀,分散性好,大多呈圆球型,平均粒径为15 nm,粒径范围10~20 nm,其Zeta电位为+29.3 mV;多层修饰的纳米磁粒在pH 2.0的酸中具有很好的耐酸性能,而未处理的纳米粒子在酸溶液中发生了溶解。MTT实验结果显示,纳米颗粒与细胞有良好的生物相容性;体外细胞转染的结果表明,精氨酸修饰的纳米磁粒能介导pEGFP-N1质粒转染HepG2细胞,并在细胞中表达绿色荧光蛋白。因此,精氨酸修饰的磁性纳米颗粒作为一种新型非病毒基因载体具有介导核酸类生物大分子的应用价值。 相似文献
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Seied Mahdi Pourmortazavi Mehdi Rahimi-Nasrabadi Morteza Khalilian-Shalamzari Hamid Reza Ghaeni Seiedeh Somayyeh Hajimirsadeghi 《Journal of Inorganic and Organometallic Polymers and Materials》2014,24(2):333-339
Copper tungstate nanoparticles were synthesized by a chemical precipitation reaction in aqueous ambient involving direct addition of copper ion solution to the solution of tungstate reagent. Optimization of the synthesis procedure was carried out using Taguchi robust design as a statistical method. In order to controllable, simple and fast synthesis of copper tungstate nanoparticles, effects of some synthesis conditions such as reagents concentrations (i.e., copper and tungstate ions), flow rate of copper feeding and temperature of the reactor on the particle size of synthesized copper tungstate were investigated by the aid of an orthogonal array. The results of optimization process showed that copper tungstate nanoparticles could be prepared by controlling the effective parameters and at optimum conditions of synthesis procedure, the size of prepared copper tungstate particles was about 56 nm. Chemical composition and microstructure of the prepared copper tungstate nanoparticles were characterized by means of X-ray diffraction, scanning electron microscopy, UV–Vis spectrophotometry, FT-IR spectroscopy and Photoluminescence. 相似文献
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In this paper, electrolysis method was used to produce copper powder particulates. The effects of parametric values, such as current density, concentration of copper ions, electrolyte temperature and rotation speed of cathode, on the morphologies and on the apparent densities of copper powders were examined. These parameters were evaluated by the current efficiency of hydrogen evolution. In addition, scanning electron microscopy (SEM) was used for analyzing the morphology of the copper powders. It was found that the increasing of the current density or the electrolyte temperature decreased the size of the powder particles promoting their morphology into dendritic structure. In contrast, the increase of copper ion concentration or rotation speed of cathode also increased the size of the particles resulting in a cauliflower-like morphology. All powder particles obtained were consisted of agglomerated copper grains. The most important difference was the size and the shape of the copper grains which were notably influenced by the electrolysis parameters. The apparent density values of copper powders were found to be suitable for many powder metallurgical applications. Attempts were also made in the later part of the paper to determine optimum process parameters for the production of electrolytic copper powders. 相似文献
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非水溶剂法制备纳米铜粉 总被引:1,自引:0,他引:1
研究了以甘油作为还原剂,聚乙烯吡咯烷酮(PVP)作为分散剂,在液相甘油体系中还原醋酸铜(或氧化铜、氢氧化铜)制备纳米铜粉的方法。通过实验探索得到了最佳制备工艺条件:50 mL甘油体系中加入适量铜盐并使铜盐和甘油的物质的量比达到1∶[KG-*2]40、同时加入分散剂PVP 0.4~0.6 g,控制温度为475~505 K,快速搅拌反应50~60 min。所得产物通过化学分析,粉末X射线衍射(XRD)、透射电镜(TEM)表征,结果表明产物铜粉纯度比较高,粒径符合纳米材料的要求,并且粒子呈球型分布。 相似文献
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通过实验对比分析了带有单相自然循环回路元件的铜板与光滑铜板相隔冷热空气逆流换热的换热效果。 结果表明,相同泵耗功情况下,加装单相自然循环回路元件的换热板的换热量是光滑铜板的1.1~1.3倍。在此基础上,本文通过数值模拟进一步对比分析了加装单相自然循环回路元件与相同形状、尺寸的铜翅片换热效果,针对影响自然循环回路传热性能的主要因素,如循环回路高度、横向与轴向倾斜角度、冷热源温差等,进行了数值模拟研究。结果表明:只有当温差超过等效温差点后,自然循环回路元件的换热效果才强于相同形状和尺寸的铜翅片;随着几何尺寸减少以及倾斜角度的增加,自然循环元件与铜翅片的等效温差点随之升高。 相似文献
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The catalyst system containing copper and cadmium oleates as used in selective hydrogenations was analyzed. The reddish brown reaction mixture as such and after precipitation by alcohol was subjected to polarographic, spectroscopic, x-ray and electron-microscopic analysis. The conclusion drawn was that the mixture is a heterogeneous system. From an electron micrograph it was observed that the average particle size is 48 Å. It was also possible to determine the mean degree of oxidation of copper in the precipitate, the results indicating that the copper is in its metallic state. Cadmium is present as cadmiumoleate, which stabilizes the copper colloid during the reaction. 相似文献
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Copper nanoclusters were synthesized by a chemical reduction of an aqueous copper salt solution by sodium borohydride. A polyaniline nanocomposite containing copper nanoclusters was prepared by polymerizing a monomer aniline hydrochloride solution containing the copper nanoclusters using ammonium persulfate as an oxidizing agent. The synthesized nanocomposite was characterized using various techniques such as UV‐visible spectroscopy, FTIR spectroscopy, X‐ray diffraction (XRD), and transmission electron microscopy (TEM). The presence of copper was confirmed by XRD and the size of the copper clusters was found to be ~53 nm, which is in good agreement with that obtained from the TEM. The synthesized nanocomposite was used to serve as a catalyst in a Wacker oxidation reaction for the conversion of 1‐decene to 2‐decanone in the presence of molecular oxygen. The formation of 2‐decanone was confirmed using GC‐MS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2412–2417, 2003 相似文献
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以1-甲基-3丁基咪唑氯离子液体为溶剂直接溶解氯化铜,硫化钠水溶液作为沉淀剂快速制得片状硫化铜纳米颗粒.对比实验揭示,离子液体对于片状硫化铜纳米结构的形成具有决定性的影响.UV-Vis光谱检测显示其在240到600 nm处有较宽的吸收峰. 相似文献
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Effects of two additives, thiourea and saccharin, on copper electrodeposition from acid sulphate solutions were investigated by different electrochemical methods (cyclic voltammetry, chronoamperometry, and electrochemical quartz crystal microbalance) as well as by different observation techniques (scanning electron microscopy and atomic force microscopy). The morphology of copper coating obtained with thiourea leads to a smooth and bright deposit whereas it is only slightly modified by saccharin. The electrochemical reactions of copper electrodeposition were modified by the formation of complexes between thiourea and copper. However, in presence of saccharin, the kinetics and morphology of copper coating remain unchanged. From X-ray photoelectron spectroscopy analysis, thiourea was found to react with copper or copper ions by strong bond formation between the sulphur atoms of thiourea molecule and copper. This is the evidence of the adsorption of thiourea on the coating. Moreover, the thiourea action starts in the initial stages, allowing a homogeneous nuclei size and a large nuclei density. Finally, the nucleation mechanism of electrodeposition appears to be modified according to the additives used. 相似文献