有机物对低温超强碱法制备纳米四方多晶氧化锆粉体性能的影响

利用低温超强碱法制备出了纳米四方多晶氧化锆粉体。为改善该粉体分散性较差、氧化钠含量较高的缺点 ,用有机物对粉体进行了表面改性处理 ,采用X射线荧光光谱、X射线衍射、透射电镜等对粉体性能进行了分析。结果表明 ,采用无水乙醇和柠檬酸铵对粉体进行改性处理 ,使得粉体粒度均匀、分布变窄 ,形态近球形 ,其中柠檬酸铵的处理效果尤为显著 ,使粉体平均粒径从 0 .6 9μm减小到 0 .5 4μm ;进一步的高分辨像分析结果表明 ,粉体颗粒多由 2～ 3个大小为 2 0～ 30nm的单晶组成 ,较大的团聚体较少 ,因此有机物对粉体的表面改性处理有利于获得分散性好、粒度均匀的高质量纳米氧化锆粉体。     

KH560改性氧化锆粉体及凝胶注模研究

采用硅烷偶联剂KH560对氧化锆粉体进行湿法改性,研究了硅烷偶联剂KH560添加量对凝胶注模成型氧化锆陶瓷性能(抗折强度、硬度和密度)及浆料性能的影响,并研究了添加量对氧化锆粉体、生坯和陶瓷显微结构的影响。结果表明:采用KH560改性氧化锆粉体可改善粉体团聚,烧结后获得高强度高致密性的氧化锆陶瓷。当KH560添加量为0.8 wt%,可获得悬浮性良好且粘度为425.7 mPa·s(固含量50%)的浆料,密度、气孔率、硬度和抗折强度分别为6.013 g/cm~3、0.019%、90±2.23 HRB和843.92 MPa的氧化锆陶瓷。通过SEM观察,改性后,氧化锆粉体团聚减少,生坯和陶瓷气孔、团聚减少,颗粒较改性前分布较为均匀,内部结构较为致密。     

微米稀土粉体表面改性技术研究

本文采用稀土粒子与蛇纹石粉体组成的微米复合粉体,研究了油酸、Span、硼酸酯对其的表面改性效果,确定了复合改性剂的复配配比为油酸∶Span∶硼酸酯=43.1∶24.1∶32.8。通过实验,得到了较优工艺条件:复合改性剂添加量5.8%,改性温度75℃,改性时间80min。改性后的微米稀土粉体表现出良好的亲油疏水性,提高了其在机油中的分散稳定性。     

ZrO_2表面改性及凝胶注模研究

凝胶注模成型工艺能够制备出高强度,高致密性,且形状复杂的氧化锆陶瓷。粉体团聚对凝胶注模成型工艺存在不良影响,粉体团聚导致陶瓷内部产生缺陷,导致致密性、均匀性变差,力学性能降低。本文通过对氧化锆粉体表面改性,改善粉体团聚,将改性粉体用于凝胶注模成型,制备出低粘度浆料。通过SEM、粘度仪、显微镜等仪器,对强度、粘度及粉体分散情况进行表征。结论 :当钛酸酯偶联剂加入量为0.4 wt%时,粉体团聚情况以及粘度达到最佳,当固相含量为50%时,粘度达到557.6 mPa·s,抗弯强度达到710.08 MPa,洛氏硬度达到92 HRB;断面观察,改性后陶瓷内部颗粒间结合较为紧密,结构均匀。     

分散剂对氧化锆晶型的影响

以氧氯化锆为原料、尿素为沉淀剂,采用不同表面活性剂为分散剂,制备超细氧化锆粉体。实验研究发现,其他条件相同,采用聚乙二醇和聚乙烯醇作分散剂,所制得的氧化锆粉体以单斜晶为主,同时有一定量的四方晶氧化锆生成,且添加聚乙二醇生成的四方晶氧化锆较添加聚乙烯醇时生成的多;采用Span80作分散剂,明显抑制了四方晶氧化锆的生成,可制得较纯的单斜晶氧化锆粉体。另外,采用不同分散剂所制得的产物颗粒形状不同,用聚乙二醇作分散剂可制得纺锤形氧化锆粉体,而用聚乙烯醇或Span80作分散剂则可制得椭球形氧化锆粉体。     

改性氧化铝粉制备高性能陶瓷浆料的研究

利用油酸对氧化铝粉体进行表面改性,研究了表面改性工艺对氧化铝粉沫表面特性及粉体制备的浆料性能的影响.实验结果表明:改性后粉体表面覆盖由碳氢长链组成的非极性有机表层结构,消除粉体间的硬团聚,制备出固相体积分数达55vol%的氧化铝浆料.     

硼酸酯对微晶白云母表面改性的研究

采用正交试验研究了用硼酸酯改性微晶白云母的工艺,并通过粘度、改性粉体/聚氯乙烯复合材料的力学性能和红外光谱测试对改性效果进行了表征.结果表明:用硼酸酯改性的微晶白云母粉体在有机介质中的分散性有明显的提高,可以大幅度增加其在高分子聚合物中的填充量;用硼酸酯对粉体改性能改善粉体/聚氯乙烯复合材料的力学性质;硼酸酯主要以物理吸附方式包覆于微晶白云母粉体表面.     

一种评价塑料填料粉体改性效果的新方法

介绍一种评价塑料填料粉体性的新方法－浊度法。在对用油酸和TTS两种改性剂处理的重质碳酸钙填料粉体的改性效果进行评价的基础上，分析了这种方法的基本原理，表明这种评价手段是科学的和灵敏的。     

纳米Fe3O4的表面改性及其分析表征

分别采用油酸和硬脂酸、油酸、十二烷基硫酸钠和KH-570对纳米Fe3O4进行改性,通过红外光谱、热分析法对改性后粒子进行了表征和研究。结果表明:油酸和硬脂酸的混合酸对纳米Fe3O4的改性效果明显优于其他改性剂。     

低压条件下纳米氧化锆的水热结晶合成

本文采用水热结晶法研究了在较低压力下纳米氧化锆粉体的制备和性质。制备出了结晶完整、分散性良好、粒度约为十几纳米的超细氧化锆粉体。用XRD、TEM等测试方法对晶相组成、晶粒粒度、晶貌特征等与水热结晶温度及保温时间的关系进行了研究。并对单斜相氧化锆和四方相氧化锆的晶粒形成过程进行了讨论。     

Dispersion of Oleate-Modified CuO Nanoparticles in a Nonpolar Solvent

Two nanosized cupric oxide powders, which are synthesized by a vapor-phase reaction and aqueous precipitation, are surface modified with oleic acid to form cupric oleate on the surface. This enhances the dispersibility of cupric oxide powders in a nonpolar solvent of octane. The cupric oxide powder prepared by aqueous precipitation exhibits much better dispersion in octane than that synthesized by vapor-phase reaction. This is attributed to the presence of larger amounts of hydroxyl group on the particle surface, forming more cupric oleate and thus enhancing the colloidal stability of the resulting organic suspension.     

Liquid-phase catalytic oxidation of unsaturated fatty acids

Liquid-phase catalytic oxidation of oleic acid with hydrogen peroxide in the presence of various transition metal/metal oxide catalysts was studied in a batch autoclave reactor. Azelaic and pelargonic acids are the major reaction products. Tungsten and tantalum and their oxides in supported and unsupported forms were used as catalysts. Alumina pellets and Kieselguhr powder were used as supports for the catalysts. Tungsten, tantalum, molybdenum, zirconium, and niobium were also examined as catalysts. Tertiary butanol was used as solvent. Experimental results concluded that tungsten and tungstic oxide are more suitable catalysts in terms of their activity and selectivity. The rate of reaction observed in the case of supported catalysts appears to be comparable or superior to that of unsupported catalysts. In pure form, tungsten, tantalum, and molybdenum showed strong catalytic activity in the oxidation reaction; however, except for tantalum the other two were determined to be economically unfeasible. Zirconium and niobium showed very little catalytic activity. Based on the experimental observations, tungstic oxide supported on silica is the most suitable catalyst for the oxidation of oleic acid with 85% of the starting oleic acid converted to the oxidation products in 60 min of reaction with high selectivity for azelaic acid.     

铝锆有机金属偶联剂对超微二氧化钛表面改性

利用铝锆有机金属偶联剂对超微二氧化钛粉体进行表面改性。讨论了改性前后超微二氧化钛的润湿性、沉降体积等表面性质的变化。结果表明：改性的超微二氧化钛与水的接触角增大，在有机介质中分散性提高。通过红外光谱和能谱分析表明，在无机二氧化钛粉体表面接枝上了铝锆有机基团；通过扫描电镜可看出经过改性后的超微二氧化钛分散性得到改善。     

纳米Fe2O3的有机表面改性及表征

研究了纳米Fe2O3，有机表面改性的影响因素，确定了最优改性剂和改性条件。采用红外光谱（FT-IR）、热分析（TG）、透射电镜（TEM）和分散性实验对表面改性前后的纳米Fe2O3，进行了表征。实验结果表明，以硬脂酸为改性剂、用量为15％、pH值为8、改性时间为2h时，改性后的纳米Fe2O3的亲油化度达到89．47％。红外光谱和热分析显示，硬脂酸以化学键合的方式结合在纳米Fe2O3的表面，其质量分数约为11％。透射电镜（TEM）和分散性实验表明，经硬脂酸有机表面改性的纳米Fe2O3，具有亲油疏水性能，能较好地分散于有机溶剂二甲苯中。     

Diffuse reflectance Fourier transform infrared spectroscopy of oleic acid adsorption on silicic acid

Diffuse reflectance Fourier transform infrared spectroscopy was used to observe adsorption complexes of oleic acid and isopropanol (IPA) on silicic acid in hexane. The spectra provide definite evidence of the molecular nature of the surface interaction. In addition, the effect on oleic acid adsorption of modifying the solvent with IPA, which competes for adsorption sites and modifies the solvent polarity, was studied. Oleic acid adsorption was reduced in the presence of an equimolar IPA concentration in hexane, relative to that from hexane alone. This could be explained by a combination of competitive adsorption of IPA and IPA interacting with oleic acid in solution. IPA, in solution, and silica are probably competing for the lipid. This is additional evidence that suggests that lipid adsorption onto silicic acid is influenced by competitive adsorption. The adsorption of oleic acid and IPA, from a mixture of the two in hexane, was controlled by (i) the equilibrium between surface-bound species and molecules in solution and (ii) the polar interaction between oleic acid and IPA in solution. Thus, washing pre-bound oleic acid with hexane removed only a small amount of oleic acid, while washing with a solution of IPA in hexane removed most of the pre-bound oleic acid.     

Über die Reduktion ungesättigter Fettsäuren und deren Ester zu ungesättigten Fettalkoholen durch selektive katalytische Hochdruckhydrierung V: Die katalytische Wirkung von Mischoxiden und reinen Oxiden

Reduction of Unsaturated Fatty Acids and Their Esters to Fatty Alcohols by Selective High-Pressure Catalytic Hydrogenation V: Catalytic Action of Mixed and Pure Oxides The catalytic action of mixed oxides and pure metal oxides such as zinc-chromium oxide, zinc-iron oxide, magnesium-iron oxide and zinc oxide, chromium oxide, titanium dioxide and zirconium dioxide in the high-pressure hydrogenation is described. Substances taken for testing were methyl oleate, butyl oleate, oleic acid, methyl undecenoate and methyl linolate. Optimum combinations of catalysts and the corresponding reaction conditions are reported for oxidic catalysts. The previously postulated hypothesis on the catalytic action in the selective hydrogenation is supported by considering the semiconductor properties of the metallic oxides.     

Defluoridation of Water by Graphene Oxide Supported Needle-Like Complex Adsorbents

The dicarboxylic acids like oxalic acid, malonic acid and succinic acid mediated graphene oxide–zirconium needle like complexes were synthesized and used to remove fluoride from simulated fluoride contaminated water. The adsorption of fluoride by dicarboxylic acids mediated graphene oxide–zirconium complexes were by both electrostatic interaction at acidic pH and ion-exchange mechanism at neutral pH. The maximum defluoridation capacity observed was 9.70 mg/g at the minimum contact time of 18 min at room temperature. Various batch equilibrium parameters like pH studies, contact time, common ion interference and temperature studies were optimized. The synthesized graphene oxide and graphene oxide supported complexes were characterized using UV–vis, FTIR, XRD and SEM with EDAX analysis to establish the mechanism of fluoride adsorption. The removal of fluoride was described by the pseudo-second-order reaction kinetics, Freundlich isotherm model and thermodynamic studies which indicates the nature of adsorption was endothermic and spontaneous. Regeneration studies depict that the dicarboxylic acid mediated graphene oxide–zirconium complex can be used as an effective adsorbent for the removal of fluoride ions from wastewater. Also, the field applicability of the material has been verified with field samples collected from nearby fluoride endemic villages.     

硅灰石粉改性研究

论述先对硅灰石粉进行预处理，然后用三氧化铝等包膜剂对其进行气流包膜处理。试验结果表明，白度，消色力和分散性等都有明显提高，改性效果良好，气流色膜装置可行。     

Formation and dissolution of anodic oxide films on zirconium in NaOH: Kinetic studies

The open circuit behaviour of a mechanically polished zirconium electrode in NaOH solution revealed that the oxide building or dissolution process depended on NaOH concentration. Anodic oxide films formed at and below 30 V are fairly stable in NaOH solutions below 1 M. The oxide film is highly unstable, however, when immersed in NaOH at concentrations higher than 1 M. In such cases, oxide dissolution occurs preferentially over oxide building although its extent is much lower if compared with that occurring in acid medium. The results are in accord with the duplex nature of the oxide formed on zirconium.     

Preparation of Bi2O3@PCPA-KH590/chloroprene composites with good mechanical properties under high-filling

As a “green” radiation protection material with the potential to replace lead oxide, bismuth oxide has more research applications in the field of γ protection. However, due to their different surface properties, there are compatibility and interaction problems between metal oxides and rubber. To enhance the performance of bismuth oxide in neoprene, Bi₂O₃@PCPA-KH590 was prepared by coating bismuth oxide with polyphenol/polyamine and grafting KH590 on the surface of bismuth oxide. This allows for creating more active sites with the help of polyphenol/polyamine, enabling KH590 to be grafted onto bismuth oxide particles. The S functional group on the silane coupling agent is then cross-linked with the rubber substrate, enhancing the dispersibility of the bismuth oxide powder. This improvement not only improves the dispersibility of the bismuth oxide powder but also enhances the mechanical properties of the rubber composite material. Compared with pure CR, the mechanical properties of 60 wt% filler-modified powder composites can still be maintained at a high level, with the tensile strength reaching 12.83 Mpa. In sum, the proposed method appears feasible for preparing highly filled radiation protection rubber-based materials.