Synthesis of Silicon Dioxide Optical Films Mixed with Acrylic Series Monomers by Sol-gel Process

In this study, silicon dioxide (SiO₂) particles are mixed with acrylic series monomers (methyl metacrylate (MMA) and 2-hydroxyethyl methacrylate (2-HEMA)) by sol-gel process to prepare inorganic-organic hybrid materials for the optical film. The other optical film has the same composition and process as the above but tri(ethylene glycol) dimethacrylate (TEGDMA) is added.

An infrared spectrometer, differential scanning calorimeter, thermo gravimetric analysis, ultraviolet-visible spectrophotometer, and spectroscopic-ellipsometer have been used to explore the effect on optical, hardness, and thermal properties of the two series of thin films. TEGDMA used as a bonding resin in this study showed that not only a better hardness and thermal properties, but also maintain good optical properties in the SiO₂ hybrid materials by sol-gel process.     

Formation of Zircon from Zirconium Dioxide and Silicon Dioxide in the Presence of Vanadium Pentoxide

The high-temperature formation of zircon from zirconium dioxide and silicon dioxide in the presence of vanadium pentoxide was studied. A reaction between zirconium dioxide and vanadium pentoxide appeared to take place at about 730°C. That reaction product then reacted with silicon dioxide to form zircon. The experiments suggest that such zircon contains a few per cent of tetravalent vanadium in solid solution and has a light blue color. It appeared that the end product under equilibrium conditions would be pure zirconium silicate since vanadium pentoxide or tetroxide was liberated under prolonged heating. Zircon also formed from silicon dioxide and zirconium dioxide in the presence of niobium or tantalum pentoxide.     

二氧化钛溶胶的含量对耐磨涂层性能的影响

以有机硅氧烷为先驱体,采用溶胶-凝胶法结合流平法在PMMA表面制备有机/无机耐磨涂层,研究了二氧化钛溶胶的含量对耐磨涂层硬度、耐划伤性及耐磨性的影响,利用ND J-1旋转黏度计、WGFS透光率/雾度测定仪、Taber 5151耐磨仪等分析表征涂层的性能。结果表明:加入二氧化钛溶胶后,钛原子取代了部分硅原子的位置,从而使形成的含有S i—O—Ti的有机无机三维立体网络结构,比只含S i—O—S i的有机无机三维立体网络结构的耐磨涂层性能更为优异。     

聚丙烯/纳米二氧化硅复合材料研究进展

从制备方法、相容性和增强增韧机理3个方面综述了聚丙烯(PP)/纳米二氧化硅(SiO2)复合材料的研究进展。其中,制备方法包括原位聚合法、溶胶凝胶法和超声波法;增强增韧机理包括裂缝与银纹相互转化机理、物理化学作用机理、微裂纹化机理和临界基体层厚度机理。指出了可以通过对纳米粒子进行表面改性,以降低其表面势能、调节疏水性、增加与基体之间的润湿性和结合力来改善材料的性能。     

氧化锆复合氮化硅陶瓷

分析了二氧化锆的性质及氧空位对二氧化锆相变的影响 ,讨论了二氧化锆韧化氮化硅陶瓷的影响因素 ,提出了二氧化锆韧化氮化硅陶瓷时避免氮化锆生成、促进复相氮化硅陶瓷烧结的途径。     

单分散性SiO2的制备与应用

系统地介绍了单分散性二氧化硅的制备方法及其优缺点，列举了单分散性二氧化硅在有关方面的应用；最后在归纳前人研究成果的基础上，提出了超临界流体快速膨胀法制备单分散性二氧化硅的设想。     

大粒径纳米二氧化硅的制备技术

介绍了一种制备大粒径、高浓度硅溶胶的工艺方法,研究了硅溶胶生产中影响纳米二氧化硅粒径的增长因素。结果表明,纳米二氧化硅粒径的平均大小、粒度分布受pH值、温度、杂质离子浓度等诸多因素的影响,控制条件处于最佳状态有利于二氧化硅粒径均匀提高。     

Sol-Gel法制备光固化纳米复合涂料的应用性能

运用紫外光固化技术与溶胶-凝胶（Sol-Gel）法制备紫外光固化纳米复合涂料,考察了SiO2含量及有机树脂结构对涂膜性能的影响.结果表明复合涂料中纳米颗粒具有良好的分散性,并在其表面形成良好的界面结合层;纳米SiO2的加入可以改善涂膜的硬度、附着力和抗冲性能.用该方法得到的EA/PUA纳米复合涂料光固化后涂膜具有优良的综合性能.     

改性二氧化硅／环氧树脂体系的制备

用带不饱和双键的硅烷偶联剂与SiO2表面的羟基反应导入双键，进而加入有机单体丙烯酸缩水甘油醚进行自由基共聚，达到了对SiO2表面的复合改性。根据改性前后SiO2表面的接触角、含水率、吸油值的测定结果，表明复合改性后SiO2的憎水性和亲油性得到改善；把改性前后的SiO2样品与环氧树脂混合固化，测试了复合材料的力学性能，发现改性SiO2复合材料的拉伸强度增加了35％，弯曲强度增加了42％；同时用SEM对复合材料的断面观察发现：改性SiO2颗粒与环氧树脂问无明显的界面，其亲合性优于未改性SiO2。     

Electron Cyclotron Resonance Plasma-Enhanced Metalorganic Chemical Vapor Deposition of Tantalum Oxide Thin Films on Silicon near Room Temperature

Films of tantalum oxide, ranging in thickness from 25 to 2000 nm, were successfully deposited on silicon by the electron cyclotron resonance plasma-enhanced metalorganic chemical vapor deposition (ECR-MOCVD) process at deposition rates of up to 33 nm/min. The films were produced by decomposition of tantalum pentaethoxide into tantalum oxide in an oxygen ECR microwave plasma. The films were amorphous (but fully dense) since the temperature of the substrate, which was unheated, was estimated to be 76–120°C. The growth of the tantalum oxide films was accompanied by the formation of an interlayer of silicon dioxide at the silicon interface. The tantalum oxide films were oxygen rich (relative to Ta₂O₅). The effective relative dielectric constant of these dual-layer dielectrics ranged from ɛ_ef= 8.5 to 24; this range was explained in terms of a bilayer consisting of a 13-nm-thick silicon dioxide layer of ɛ_sx= 4, and a tantalum oxide overgrowth of varying thickness having ɛ_tx∼ 25. A maximum breakdown strength of the films was 6.9 MV/cm and the leakage current at a field of 1 MV/cm was 3.0 × 10^-8. The breakdown properties were related to the presence of stray particles on the substrate; these properties are expected to improve considerably if the processing is carried out in a clean-room environment. The silicon dioxide layer is believed to have grown by the diffusion of oxygen through the tantalum oxide overlayer despite the low substrate temperature.     

二氧化硅在皮革涂饰剂中的应用研究

介绍了二氧化硅在我国皮革处理应用中的一些情况,结合这些应用,分析了二氧化硅的特性以及使用过程中出现的问题,并着重分析了二氧化硅粒度分布、消光性能等关键问题。     

Preparation of Silicon Dioxide with a Fixed Content of Fluorine from Fluorosilicic Acid

The process of obtaining silicon dioxide upon the interaction of fluorosilicic acid with an aqueous solution of ammonia is studied. The fluorine-containing compounds in synthesized dioxide are identified by ¹⁹F NMR spectroscopy. It is shown that the two-stage method of precipitation followed by washing, allows producing silicon dioxide with a fluorine content of units of ppm.     

原位生成纳米SiO_2及其作为填料对聚氨酯硬质泡沫塑料性能的影响

通过选择适当的乳化剂和水解温度以及控制水对于乳化剂的摩尔比,采用油包水微乳液法在聚醚多元醇中原位合成了纳米SiO2,然后该聚醚多元醇进一步与TDI反应制备出聚氨酯硬质泡沫塑料。TEM照片显示原位合成的SiO2微粒呈球状且分散,粒径分布在50nm-70nm。该聚氨酯硬质泡沫塑料的吸水率,随着SiO2填加量的增加,先升高随后又降低。因为原位生成纳米SiO2的加入,聚氨酯硬质泡沫塑料的拉伸强度得到显著提高,冲击强度缓慢增大,而对于压缩强度则先轻微降低,一直到SiO2的含量为0.9wt%时才开始急剧增大。     

金属陶瓷涂层耐蚀性能研究

采用溶胶－凝胶浸渍提拉法在不锈钢、纯铜及铝合金基体上制备具有保护性的ＳｉＯ２、ＺｒＯ２、ＴｉＯ２、Ａｌ２Ｏ３及ＳｉＯ２－ＴｉＯ２陶瓷涂层,利用阳极极化曲线的、循环动电位极曲线、点蚀电位的测量以及三氯化铁和５％硫酸介质中的腐蚀试验研究了所得陶瓷涂层的耐蚀性。结果表明,这些陶瓷涂层能大幅芳提高金属基体在各种腐蚀介的耐蚀性。     

非水环境中球磨作用对改性SiO2晶体结构、粒度和Zeta电位的影响

以市售SiO2粉体为主要研究对象,采用X射线衍射线形分析、激光粒度分析和Zeta电位分析等表征手段,研究了球磨作用对改性SiO2晶体结构、粒度和Zeta电位的影响. 结果表明,SiO2分别经空气气氛中干磨、以N,N-二甲基甲酰胺(DMF)为球磨分散介质的湿磨、以二甲基甲酰胺(DMF)为球磨分散介质和以硅烷偶联剂KH-560为改性剂的湿磨后,其结构性质有显著差异,分别经过3 h球磨后,干磨、湿磨、添加10%硅烷偶联剂并湿磨和添加20%硅烷偶联剂并湿磨后SiO2平均晶粒尺寸分别为46.9, 31.4, 24.5和75.9 nm,其平均晶格畸变率分别为0.0253%, 0.0871%, 0.117%和0.063%,中位粒径分别为4.241, 1.586, 1.321和5.092 mm.     

纳米TiO2薄膜制备方法的研究进展

纳米二氧化钛以其优异的化学、物理性能受到关注。薄膜是纳米二氧化钛的重要形式,制备纳米二氧化钛薄膜具有重要意义和很好的应用前景。依据制备工艺中温度的要求,对制备纳米二氧化钛薄膜的方法进行了概述,高温制备的工艺主要有溶胶-凝胶法、水热法、气相沉积法,低温制备工艺主要有电泳沉积法、紫外光照射法、电化学制备法、模板自组装制备法。     

纳米二氧化硅包覆云母氧化铁及其对UV固化涂料防腐性能的影响

采用溶胶-凝胶法在云母氧化铁表面上包覆纳米二氧化硅对其进行改性。采用红外光谱(FTIR)、能谱(EDS)和热重分析(TG)确定纳米二氧化硅是否包覆于云母氧化铁表面;扫描电镜(SEM)观察了云母氧化铁包覆前后的表观形貌变化;利用EIS技术研究了云母氧化铁经改性后对涂层耐腐蚀性的影响。结果表明:包覆在云母氧化铁表面的SiO_2颗粒大小一致,粒径大小约为40 nm;纳米SiO_2包覆云母氧化铁后使其表面具有纳米材料特性,从而提高了云母氧化铁的耐热性和疏水性,因此极大地增强了涂层的耐腐蚀性能。     

单分散大粒径介孔二氧化硅微球的制备及表征

以正硅酸四乙酯(TEOS)为硅源、N,N-二甲基甲酰胺(DMF)为乳化致孔剂,采用酸催化法得到部分缩合的聚硅酸乙酯(PES),再经碱进一步催化得到介孔二氧化硅微球。分析了酸催化剂用量、旋蒸温度对PES粘度及聚合程度的影响以及PES粘度对二氧化硅微球粒径的影响,并研究了氨水用量、乳化致孔剂种类、乳化致孔剂用量以及搅拌速度和后处理方式对二氧化硅微球性质的影响。利用扫描电子显微镜、旋转粘度计、氮吹吸附仪、傅里叶变换红外光谱仪等对所得微球进行表征。结果表明,所制备的介孔二氧化硅微球球形完整,粒径分布均匀,纯度高,微球平均孔径为10.164 4 nm,孔体积为1.023 023 cm³/g,比表面积为396.528 1 m²/g。     

溶胶凝胶法制备TiO2实验条件的考察

实验以钛酸正丁酯为前驱体，采用溶胶凝胶法制备二氧化钛。设计正交试验，考察水、乙醇、冰醋酸、pH值和凝胶温度对凝胶时间和状态的影响。对凝胶时间的影响程度依次为：pH值、乙醇量、凝胶温度、冰醋酸量、水量。确定溶胶凝胶法合成二氧化钛最佳条件为：pH值为2-3、乙醇的量22～28mL、凝胶温度为55～65℃、冰醋酸的量1．75～2．5mL、水的量2．0～2．5mL。     

超微二氧化硅粉体的制备及脱除羟基

采用醇盐水解法制备超微 SiO2,考察了不同反应温度、搅拌强度和不同异丙醇和正硅酸乙酯摩尔配比对 SiO2 粒度的影响,得到了最佳反应条件,在此条件下制备了超微 SiO2;采用扫描电子显微镜对制备的 SiO2 样品进行表征,结果表明 SiO2 颗粒为规则的球形,粒径均匀;红外光谱图和成分分析表明该方法制备的样品中含有大量的羟基,本文进行了脱除羟基的研究,为研究羟基脱除机理奠定基础,实验结果表明,SiO2 中羟基脱除彻底.