直接沉淀法制备纳米氧化锌工艺研究

提供一种以醋酸锌与碳酸氢铵为原料，添加表面活性剂，直接沉淀法制备纳米氧化锌的新工艺。讨论了反应物浓度和配比、反应温度、反应时间、前驱物碱式碳酸锌热分解温度对纳米氧化锌形成的影响。采用透射电镜（TEM）、X射线衍射（XRD）、热重／差热分析（TG／DTA）等方法对制备的纳米氧化锌进行表征，结果为：制得的氧化锌的平均粒径在20—80nm，晶型为六方晶系。     

纳米氧化锌的制备及表面改性技术进展

综述了纳米氧化锌的制备方法以及表面改性技术进展,提出了其今后的发展方向。     

钛酸酯偶联剂改性纳米氧化锌及在天然橡胶中的应用

采用不同用量钛酸酯偶联剂对纳米氧化锌进行表面改性，通过正交试验来确定最佳的改性条件。用活化指数表征改性效果。实验结果表明：最佳的改性条件为钛酸酯用量在3％，温度30℃，搅拌时间90min，活化指数可达到99．83％。并将在最佳条件下改性过的纳米氧化锌应用到天然橡胶中，其Ts1、t90均延长，拉伸强度、拉断伸长率、屈挠性均提高，但是胶料的撕裂强度和耐磨性能下降。     

钛酸酯偶联剂改性纳米氧化锌的研究

采用钛酸酯偶联剂对纳米氧化锌进行表面改性，研究钛酸酯偶联剂和异丙醇用量以及改性条件对改性效果的影响。试验结果表明，钛酸酯偶联剂／纳米氧化锌质量比为0．03、异丙醇用量为40．76mL、反应温度为30℃、反应时间为90min时，活化指数达到99．04％；透射电子显微镜观察发现，改性纳米氧化锌的分散性较好。     

纳米氧化锌改性PA6复合材料的制备及性能研究

利用熔融共混法制得了纳米氧化锌改性PA6复合材料,并研究了其有关性质。结果表明:纳米氧化锌能有效改善PA6的力学性能,其添加量在3%时材料力学性能最佳。结晶及热分析研究表明纳米粒子能有效限制PA6分子链段运动,使其结晶度下降。     

纳米氧化锌的制备及表面改性技术进展

介绍纳米氧化锌的制备方法以及表面改性技术进展。沉淀法是纳米氧化锌工业化生产方法,产品粒子小,粒径分布窄,分散性好。纳米氧化锌表面改性方法主要有表面包覆改性法、表面化学改性法、机械化学改性法和外膜层改性法等。     

纳米氧化锌的制备和晶粒生长动力学

以硫酸锌和碳酸铵为原料,用直接沉淀法制得纳米氧化锌的前驱体,然后煅烧得到纳米氧化锌.通过控制煅烧温度可以控制粒子的大小,并用TG-DTG、XRD、BET和TEM等测试手段对前驱体和产品进行了表征.TG-DTG分析表明,前驱体为Zn4(OH)6CO3.TEM分析表明产物颗粒基本为球形.XRD和BET结果表明,随着煅烧温度的提高,纳米氧化锌晶粒迅速长大,并得出了纳米氧化锌晶粒生长的动力学规律.     

纳米氧化镁粉体的表面改性研究

研究并确定了最佳改性剂.对以月桂酸钠作改性剂进行了工艺条件的研究,用活化指数对改性效果进行了评价.研究结果表明,改性剂用量为15%(改性剂占氧化镁的质量分数)、改性时间为60 min、改性温度为40℃、改性pH为6时,氧化镁的改性效果最好.对改性前后的纳米氧化镁做了透射电镜(TEM)和红外光谱(IR)测试.分析结果表明:表面改性后的纳米氧化镁粒子呈疏水性,分散性好且粒径变化不大;氧化镁粒子和改性剂之间既有物理吸附又发生了化学键合.     

超声波一直接沉淀法制备超细氧化铁

将超声波用于以硫酸亚铁铵、草酸为原料的直接沉淀法制备超细氧化铁。对氧化铁的前驱体——草酸亚铁的合成及焙烧工艺进行了详细研究。讨论了反应温度、物料浓度、超声沉淀反应时间以及焙烧温度、焙烧时间对氧化铁粒度的影响。结果发现，在一定的试验条件下，可获得粒度小于40nm的氧化铁。XRD实验表明，所合成的Fe2O3为α型，TEM的测试结果平均粒径为20nm，且分散性好。     

纳米ZnO/CeO2复合氧化物的制备及其改性

以燃烧法制备氧化锌并以其为包裹对象用沉淀法合成ZnO/CeO₂复合氧化物,采用XRD、SEM 、IR、TG-DTA、UV-Vis、TEM对样品进行表征,结果表明氧化铈以包覆形式与氧化锌形成复合氧化物。用改性剂对复合氧化物进行改性研究,以亲油化度考察改性剂的类型、改性剂的用量、改性温度、pH值对改性效果的影响。实验结果表明:当选用硬脂酸钠为改性剂且用量为ZnO/CeO₂的4%,改性温度为60℃,pH值为7时,样品粒径明显变小,分散性变好,亲油化度明显提高,可获得最佳改性效果。     

超声波-直接沉淀法制备超细氧化铁

将超声波用于以硫酸亚铁铵、草酸为原料的直接沉淀法制备超细氧化铁.对氧化铁的前驱体--草酸亚铁的合成及焙烧工艺进行了详细研究.讨论了反应温度、物料浓度、超声沉淀反应时间以及焙烧温度、焙烧时间对氧化铁粒度的影响.结果发现,在一定的试验条件下,可获得粒度小于40 nm的氧化铁.XRD实验表明,所合成的Fe2O3为α型,TEM的测试结果平均粒径为20 nm,且分散性好.     

Preparation and photocatalytic kinetics of nano-ZnO powders by precipitation stripping process

Ultra-fine zinc oxalate powders were prepared through a precipitation stripping method with bis(2-ethylhexyl) phosphate (HDEHP) diluted by tetrachloride carbon as the extractant, and oxalic acid ethanol aqueous solution as the re-extractant and precipitator. Zinc oxide powders were obtained by decomposing zinc oxalate powders at 450uC. The prepared zinc oxide powders were characterized by transmission electron microscope (TEM), Scanning electron microscope (SEM), Thermogravimetric analysis (TG), X-ray diffraction (XRD) and Fourier transmission infrared (FT-IR) spectrum. The photocatalytic performance of methylene blue by zinc oxide was studied based on the Langmuir model and Photo-Layer model. The results show that some zinc oxide powders were micro-multipore materials with hexagonal crystal. The particle size was around 32 nm. The photocatalytic process was the control step in the chemical reaction. The photo catalytic process followed pseudo-first order kinetics and •OH concentration inside the photo-layer in different reaction condition were calculated according to the Photo-Layer model. __________ Translated from Transactions of Beijing Institute of Technology, 2007, 27(7): 641–645 [译自: 北京理工大学学报]     

纳米ZnO的表面改性及ZnO/UPR复合材料的制备

以无水乙醇为介质,用油酸和硬脂酸对纳米ZnO进行表面改性,将改性后的纳米粒子以粉末形式直接加入或制成苯乙烯悬浮液的形式经过高能超声作用加入不饱和聚酯(UPR)中制备ZnO/UPR复合材料。通过亲油化度、红外图谱来表征油酸和硬脂酸的改性效果。通过TEM分析粒子在UPR中的分散效果。在万能试验机上测量ZnO/UPR复合材料的弯曲强度。结果表明,油酸改性纳米ZnO的效果好于硬脂酸,高能超声作用可以很大程度提高纳米粒子在树脂体系里的分散性,粒子以苯乙烯悬浮液的形式加入UPR中的分散效果更好,纳米ZnO质量分数为1%时ZnO/UPR复合材料的弯曲性能最好。     

Effect of CaCO3 on the performance of Partex surface modification by ultraviolet radiation curing method

Several UV‐curable formulations containing epoxydiacrylate (EB‐600) oligomer with a tri‐functional monomer, trimethylol propane triacrylate (TMPTA), and photoinitiator Irgcure‐369 were developed to improve the surface of Partex. Filler or extender CaCO₃ was incorporated into the solution. Thin polymer films were prepared on glass plate with these formulated solutions and finally applied on polished Partex surface, and both were cured under UV‐radiation. The properties of UV‐cured thin films were studied as a function of CaCO₃ concentration. Pendulum hardness and gel content were found to decrease on glass plate with the increase of CaCO₃ concentration. Pendulum hardness, scratch hardness, and abrasion resistance of the cured Partex were found to be higher with the increase of CaCO₃ content up to 4%. Thus, the formulation containing 4% CaCO₃ showed the best performance over all formulations containing CaCO₃. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1858–1867, 2001     

超声辐射下钯系加氢催化剂的新型制备方法

提供了一种钯系加氢催化剂新型制备方法。采用经β-环糊精改性载体,以醋酸钯为活性组分前驱体在超声辐射下进行催化剂有机相制备;并以碳三液相加氢为探针反应,对利用4种不同方法制备的催化剂进行200 h对比评价。结果表明,该方法可有效提高活性组分分散度,使催化剂在保持较好加氢活性的同时具有较好的加氢选择性,为优化钯系加氢催化剂综合性能提供一条行之有效的途径。     

Surface modification on nanoscale titanium dioxide by radiation: Preparation and characterization

Electron beam mutual radiation to induce graft polymerization has been carried out respectively, between nanoscale anatase‐ or rutile‐titanium dioxide particles surface and methyl methacrylate (MMA). The composition and properties of surface modified titanium dioxide were investigated by a number of surface sensitive techniques: X‐ray photoelectron spectrum (XPS), FTIR, X‐ray diffraction (XRD), and NMR. Results of the technological measurements show how surface chemistry is affected throughout the surface modification process, finally leading to a complete and homogeneous vinyl compound overlayer on top of the titanium dioxide samples. In comparison with stereochemical structures of the graft molecular chains and the PMMA induced by radiation polymerization, the surfaces of the oxides are considered to provide a template for the graft polymerization. The grafted titanium dioxide is found to produce a stable colloidal dispersion, in good solvents for the grafted polymer, and the dispersibility of grafted dioxides is influenced by temperature. In addition, the wettability of the surface of titanium dioxide to water is readily controlled by grafting of hydrophilic or hydrophobic polymers. Based on the above results, it is concluded that MMA is covalently linked to the surface of titanium dioxide by a surface modification process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 100: 3510–3518, 2006     

纳米铟锡氧化物粉体的制备及表面改性

在水介质中通过化学共沉淀法制备了铟锡氧化物(ITO)粉体，利用表面处理剂对ITO颗粒进行表面包裹。采用X-射线衍射分析仪、透射电镜、红外光谱分析仪、差热分析仪等分析了该ITO的物相结构及表面形貌。结果表明，该ITO为锡掺杂的三氧化二铟晶体，经表面包裹后，成为粒径均匀、大小约为50nm、无团聚的纳米粒子。经静态沉淀法分析，该纳米粒子在有机物(MMA)中有良好的分散性。     

超声辐射固体氢氧化钠催化合成阿司匹林的研究

以水杨酸和乙酸酐为原料,固体氢氧化钠为催化剂,采用超声辐射快速合成阿司匹林,用正交实验筛选出最佳合成条件为:n(水杨酸)∶n(乙酸酐)=1∶2.5,超声辐射功率160 W,催化剂用量为水杨酸质量的10%,反应温度40℃,辐射时间8 m in,产率93.0%。研究表明该法具有操作简单、快速、后处理简单、产率高的特点,符合清洁生产的要求。