溶胶-凝胶法制备环氧/SiO2纳米杂化材料及其性能研究

以异氰酸丙基三乙氧基硅烷(IPTS)接枝环氧树脂(EP)合成出了一种新型的环氧预聚物(IEP),由IEP通过溶胶-凝胶法制备出了EP/SiO2杂化材料。通过FT-IR、AFM、TG、DMA表征和分析了杂化材料的化学结构、SiO2纳米粒子在EP基体中的分散性和无机纳米粒子的引入对EP树脂热性能和力学性能的影响。结果表明,原位生成的纳米SiO2粒子在EP基体中的分散性良好,其平均尺度约为50nm;杂化材料的热性能和力学性能相比于纯EP有了很大程度的提高。     

溶胶-凝胶法制备纳米复合材料的研究进展

溶胶-凝胶法用于制备纳米粒子复合材料，因组分、制备途径和结构等可优化设计，故产物性能优异。本文介绍了溶胶-凝胶法制备的纳米粒子复合材料在光学、电子、磁学、生物、催化等领域的应用和最新研究进展。     

锐钛矿型TiO2纳米棒薄膜的溶胶-凝胶法制备研究

以钛酸丁酯Ti（OC₄H₉）₄、冰醋酸、去离子水和聚乙二醇（PEG）1000为原料,采用溶胶-凝胶法和旋转涂膜工艺,在玻璃衬底上制备出锐钛矿型TiO₂纳米棒。利用X射线衍射仪（XRD）、SEM和紫外可见光谱（UV/Vis）对TiO₂纳米棒薄膜进行了表征。结果表明,实验制备的TiO₂纳米棒为锐钛矿晶型,在TiO₂反应体系中,胶体粒子在加热过程中偶联在一起,1h后形成了TiO₂纳米棒,其直径为30～50nm,长度为100～200nm。同时,在42mL钛的胶体溶液中添加0.30g PEG（1000）后,纳米TiO₂薄膜的可见光透射峰值降低,TiO₂薄膜表面孔径为20～50nm。     

溶胶-凝胶法制备纳米TiO2

用溶胶 -凝胶法制备纳米TiO2 粉晶。用X射线粉末衍射 (XRD)对不同温度热处理的系列粉末进行了研究 ,结果表明用溶胶 -凝胶法制备的TiO2 纳米晶其晶型转变温度与凝胶时间有关     

溶胶-凝胶-冷冻法制备纳米TiO2及其表征

为解决纳米TiO2粉体易产生团聚的问题,采用溶胶-凝胶与冷冻干燥法制备纳米TiO2粉体.通过X射线衍射、扫描电子显微镜和紫外分光光度计对纳米TiO2粉体的物相组成、形貌和光催化活性进行了表征.实验结果表明:在400℃下所制得的TiO2纳米粉体的粒径约为6 nm,且粒度分布均匀,呈球形;所制得的TiO2纳米粉体在投加量为2 g/L时可使质量浓度为20 mg/L的甲基橙溶液在2.5 h内几乎全部降解.溶胶-凝胶与冷冻干燥法再结合阶段升温焙烧法可得到分散性好、粒径小和光催化活性好的粉体.     

溶胶-凝胶法在PMMA上制备SiO2-Al2O3涂层过程的研究

采用溶胶-凝胶法,以无机盐AlCl     

溶胶-凝胶法制备HMX-AP-SiO_2纳米复合含能材料

以正硅酸乙酯为前驱物,采用溶胶-凝胶法制备奥克托金(HMX)-高氯酸铵(AP)-SiO2纳米复合含能材料,采用扫描电镜、X射线衍射分析、BET比表面积等方法对其结构进行表征。结果表明,HMX-AP-SiO2纳米复合含能材料是以SiO2为凝胶骨架,HMX与AP进入凝胶孔洞形成的,其具有纳米网孔结构;差热分析表明,溶胶-凝胶法制备的复合材料的热分解峰温度较物理混合相比大大提前,分解热高于物理混合物。     

溶胶-凝胶法载银SiO2杂化膜的制备及性能研究

采用溶胶-凝胶法,在甲基化改性的SiO2溶胶中掺杂硝酸银,制备Ag/M-SiO2杂化膜。通过XRD、XPS、紫外-可见吸收谱、N2吸附-脱附以及气体渗透性能测试等方法,考察了银掺杂对杂化膜结构和性能的影响。结果表明,Ag/M-SiO2膜中的银元素完全为纳米金属银,具有面心立方结构。金属银的掺杂对Ag/M-SiO2膜的化学结构基本没有影响,但使其孔径和总孔体积略微增大。与未载银的SiO2膜相比,Ag/M-SiO2膜具有更大的H2渗透速率和更好的H2/CO2选择性。金属银的引入增强了H2的表面扩散作用,促进了H2在膜中的传递,提高了SiO2膜的水汽稳定性。     

溶胶-凝胶法制备纳米二氧化钛探究

采用溶胶-凝胶法，以醇钛盐Ti（OR）4为前驱体、无水醇为有机溶剂，再把醇、水、酸混合液逐滴滴入溶液中，经凝胶化后的湿凝胶置于真空炉中干燥，得到松散干凝胶粉末，对干凝胶粉末进行热处理，得粒径为．20—100nm TiO2粒子。     

柠檬酸溶胶-凝胶法制备纳米铜

以硝酸铜、柠檬酸和氨水为原料,利用柠檬酸溶胶-凝胶法制备含铜凝胶,在氮气气氛下将干凝胶煅烧得到纳米铜粉,探讨成胶反应温度、原料配比、pH等因素对制备过程的影响,确定最低煅烧温度;采用热重-差热分析和红外光谱分析对柠檬酸溶胶-凝胶法制备纳米铜粉的过程进行分析,利用X射线衍射和扫描电镜对实验产物进行结构、形貌表征。结果表明,将柠檬酸与硝酸铜的物质的量比控制为1∶2时溶解混合,调节pH为7,在80℃下制成凝胶,在100℃下干燥后,250℃下煅烧0.5 h,可制得粒径为70⁹0 nm的球型铜粉;推断干凝胶的结构主要为柠檬酸根与铜离子以双齿配位,以及部分为桥式配位。     

Preparation of SiO2/TiO2 composite fibers by sol-gel reaction and electrospinning

Submicron scale composite fibers of SiO₂/TiO₂ with various compositions have been prepared by electrospinning a sol-gel precursor of tetraethyl orthosilicate(TEOS) and titanium(IV) isopropoxide(TiP), followed by calcination. Any gelator or binder has not been used in this direct preparation process for composite fibers, and the maximum amount of titania for suitable fiber formation was about 50 mol%. The sintered composite fibers were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. Our results show that the surface morphology and crystallization behavior of electrospun fibers are largely influenced by the calcination temperature and the content of TiO₂. XRD results also reveal that the anatase phase in composite fibers can be preserved even after high temperature processing at lower content (x = 0.1, 0.2) of titania.     

Cryogenic properties of SiO2/epoxy nanocomposites

SiO₂/epoxy nanocomposites were prepared using diglycidyl ether of bisphenol-F (DGEBF) type epoxy and tetraethylorthosilicate (TEOS) via the sol-gel process. Silica nanoparticles were collected after burning off the matrix resin and the silica nanoparticles were observed using TEM. The cryogenic tensile properties at 77 K and thermal expansion coefficient of the nanocomposites were studied. The tensile properties at room temperature were also given to compare with the cryogenic tensile properties. The fracture surfaces were examined with scanning electron microscopy (SEM). The effects of silica nanoparticle content have been studied on the cryogenic tensile and thermal properties of the nanocomposites. In addition, the dependence of the glass transition temperature on the silica nanoparticle content has also been examined.     

Preparation and electrical conductivity of SiO2/polypyrrole nanocomposite

In the present study we have chemically polymerized silica/polypyrrole (SiO₂/PPy) nanocomposite in the presence of sodium dodecyl benzene sulfate (SDBS) as dopant and iron chloride (FeCl₃) as oxidant. The SiO₂/PPy nanocomposite presents an electrical conductivity of 32.41 S cm⁻¹ and percolation threshold of 20 wt%. The resulting SiO₂/PPy nanocomposites have been extensively characterized in terms of their molecular structure, particle size, morphology, stability, and electroactivity. These SiO₂/PPy particles have a rather polydisperse morphology. The effects of synthesis parameters such as oxidant, PPy, SDBS, reaction temperature and time, on the electrical conductivity of the nanocomposite have been detailedly optimized. And the conducting nanocomposite presented a good environmental stability.     

Magnetic/SiO2 nanocomposite thin films prepared by sol-gel dip coating modified method

Nanocomposite thin films of Spinel Iron-Oxide and SiO₂ have been prepared with sol-gel dip-coating technique involving the synthesis of a ferrofluid, which has been stabilized in absence of organic media and led to the formation of magnetic nanoparticles. Structural and morphological characteristics of the synthesized ferrofluid and the relevant derived nanocomposite films are reported, as determined from X-ray diffraction (XRD), Raman, Fourier-transform infrared, Mössbauer and Ultraviolet-visible experimental techniques. Scanning electron microscopy, atomic force and magnetic force microscopy results are also reported. The synthesized ferrofluid, composed of magnetic nanoparticles of an XRD estimated average size of 18 nm, exhibit Raman spectra characteristic of a maghemite phase. These ferromagnetic nanoparticles retained their nanostructure after being inserted into the as prepared films. After heat treatment under Ar atmosphere, the maghemite nanoparticles were transformed to non-stoichiometric magnetite, providing the final composite material with useful potential application characteristics. The calcined films reported here exhibit crack-free morphology, consisting of aggregated silica/magnetic nanoparticles, with a final average size of c.a. 100 nm, while the film roughness shows a maximum peak to peak of c.a. 10 nm.     

氧化石墨烯-SiO2杂化材料对环氧树脂拉伸性能的影响

为了提高环氧树脂的力学性能,采用一步合成法制备得到氧化石墨烯(GO)-SiO₂(GO-SiO₂)杂化材料,利用扫描电子显微镜(SEM)对杂化材料的形貌进行表征,成功制得了具有三维结构的GO-SiO₂杂化材料;将GO、SiO₂颗粒和GO-SiO₂以相同的含量(质量分数均为0.1%)添加到环氧树脂中制备复合材料,利用万能强力仪测试复合材料的拉伸性能,比较3种填料对树脂基复合材料拉伸性能的影响;再分别将质量分数为0.1%、0.3%和0.5%的GO-SiO₂添加到环氧树脂中制备GO-SiO₂/环氧树脂复合材料,比较不同质量分数的GO-SiO₂对树脂基复合材料拉伸性能的影响;利用SEM对拉伸样条的断截面进行扫描测试,分析了不同种类和不同比例的填料对树脂基复合材料的增强增韧效果,并分析其增强增韧机制。结果表明: GO-SiO₂的增强增韧效果明显优于GO和SiO₂颗粒,当GO-SiO₂的添加质量分数为0.3%时,其增强增韧效果最佳。     

Preparation and characterization of sol-gel derived Er-Yb codoped SiO2/TiO2 core-shell nanoparticles

The Er³⁺-Yb³⁺ codoped silica/titania core-shell nanoparticles were prepared by hydrolysis of titanium alkoxide precursors in the presence of lanthanide ions via sol-gel method. The structure of the particles was characterized by field emission scanning electron microscopy and transmission electron microscopy. The diameter of the silica core is about 50 nm. The thickness of the titania shell is about 4 nm. A typical doping density of Er³⁺ in the titania shell is 4.51 at.%, and the one of Yb³⁺ is 12.20 at.%. The UV-vis-NIR absorption spectra and the photoluminescence spectra were also investigated.     

SiO2 / 杉木粉复合材料的制备和表征

以人工林杉木粉为原料和正硅酸乙酯( TEOS) 为无机前驱体, 依据溶剂热法反应原理, 采用溶胶凝胶的方法制备了SiO₂ / 木材复合材料。通过红外光谱分析( FTIR) 、X射线衍射分析(XRD) 、热失重分析( TGA) 、扫描电子显微镜分析(SEM) 等方法, 研究了该复合材料的结构和性能。研究结果表明, 使用这种方法, 木材的增重率显著提高。木材中的羟基与正硅酸乙酯水解后的羟基发生了缩合反应, 体系中存在Si —O —C 交联网络, 微观上形成了纳米网络结构。木质纤维素的结晶被破坏, 结晶度从75. 37 %(纯木粉) 下降到37. 42 %(木材增重率为78 %的复合体系) 。交联网络的形成显著提高了该材料的耐热性能, 使失重10 %时的热分解温度从270 ℃(纯木粉) 提高到409 ℃。      

Synthesis and properties of chitosan/SiO2 hybrid materials

This study primarily aims to explore the strength and thermal properties of various hybrid materials that are made of tetraethoxysilane/vinyltriethoxysilane (TEOS/VTES) and chitosan in different weight ratios. It is confirmed, from micro Fourier transform infrared (micro FT-IR) and nuclear magnetic resonance (NMR) analysis, that hydrogen bonds emerge between chitosan and SiO₂ in hybrid materials. With the addition of more VTES and TEOS, the surface of the hybrid material features thick granules. In addition, the mechanical performance and thermostability of both types of hybrid are better than pure chitosan. The former is enhanced with an increasing amount of TEOS until it exceeds 2.4 g and the latter is also improved with an increasing amount of TEOS.     

大尺寸大孔径C/SiO2复合导电材料的制备

以大尺寸大孔径SiO2为模板,通过丙烯腈溶液浸渍、原位聚合、溶剂蒸发制备出聚丙烯腈（PAN）/SiO2复合物,再经800℃真空炭化处理得到大尺寸大孔径的C/SiO2复合材料。用SEM、FTIR、XPS和粉末XRD对样品结构进行表征。结果表明：SiO2模板特有的毛细管效应使复合物中PAN以薄膜形式包覆在SiO2材料的三维...