纳米SiO2的光学特性研究

纳米SiO2的独特结构使其表现出一些特殊的光学特性，但文献对其紫外区光学性质的报道不一致。本文对几种不同类型的纳米SiO2进行了紫外—可见光谱测试，结果表明纳米SiO2在紫外—可见光范围内具有较强的光反射性能，但在λ=230nm附近有一强度不一的吸收峰，该吸收峰的强度可能与纳米SiO2的结构和表面状态有关。     

乙烯基三乙氧基硅烷表面改性纳米SiO2

采用硅烷偶联剂A-151处理的纳米二氧化硅(SiO2)粒子,具有良好的疏水性,并且反应副产物没有腐蚀性,有利于保护设备和环境.对改性前后纳米SiO2的表面进行研究,证明该工艺能够实现纳米SiO2的表面改性,能够有效分散纳米SiO2聚集体.红外光谱分析表明,A-151确实已经和纳米SiO2表明的羟基发生了化学反应.     

有机硅改性丙烯酸酯/纳米SiO2复合低表面能防污涂料

用逐步滴加引发剂合成有机硅改性丙烯酸树脂,将纳米SiO2、铁红、滑石粉分散于有机硅改性丙烯酸树脂中,制成低表面能防污涂料.结果表明,当纳米SiO2的加入量为5.5%～8%时,涂膜与液体的接触角大于98°,涂膜具有较低的吸水率,具有一定的防污效果.     

SiO2改性低表面能纳米结构无毒海洋防污涂料

以合成的有机硅改性丙烯酸树脂为主要成膜物质,在颜填料不变的基础上添加纳米SiO2,制成了低表面能纳米结构无毒海洋防污涂料,讨论了树脂用量和纳米SiO2对涂膜附着力及其与液体接触角的影响,分析了低表面能防污涂料的表面结构.结果表明,树脂用量为25%～30%时,涂膜的附着力为1级,涂膜与水的接触角为150°,涂膜表面为纳米-微米阶层状结构.     

甲基丙烯酸甲酯对纳米SiO2的表面接枝聚合改性研究

将经过硅烷化处理的偶联剂γ-MPS接枝到纳米SiO2表面,然后在引发剂AIBN的作用下引发单体MMA发生自由基聚合包覆.利用FTIR、TG、CA(接触角)以及TEM等手段分别表征了改性工艺条件对粒子改性前后化学组成结构、接枝率、表面亲水性以及形貌等的影响.系统研究了单体用量、引发剂用量以及反应时间对SiO2/γ-MPS/PM-MA纳米复合粒子接枝改性效果的影响.结果表明,经过PMMA接枝包覆制得了高接枝率的复合粒子,并大大改善了纳米粒子的分散性.     

纳米SiO2改性PMMA透明性的研究

本课题通过共聚、交联反应两种手段研究纳米SiO2对PMMA透明性的影响.用MMA与St共聚到一定的时候,然后加入交联剂二乙烯苯与SiO2交联固化,通过改变单体组分的比例和交联剂二乙烯苯的百分含量,使其达到要求.结果表明:改性后其力学性能与热学性能都有所提高,同时其光学性能基本没有下降.     

纳米SiO2的表面改性及其在聚氨酯弹性体中的应用

用十二烷基苯磺酸钠(SDBS) 对表面包覆Al(OH)3的纳米SiO2进行了改性处理.通过IR、自动电位粒度仪和FESEM等测试手段对表面处理前后纳米SiO2的表面结构、界面电性能和分散状况进行了分析表征.考查了处理前后纳米SiO2与聚氨酯弹性体(PUE)的相容性及其对PUE材料力学性能的影响.结果表明,经SDBS对表面包覆Al(OH)3的纳米SiO2粉体进行改性后,纳米SiO2粉体的团聚现象减少,分散性提高,单个纳米SiO2颗粒的平均粒径约为30nm;经表面处理后的纳米SiO2粉体与有机基体PUE的相容性增强,并对PUE材料的力学性能有了较大的改善,能同时达到增强增韧的效果.     

纳米SiO2疏水改性研究及应用进展

由于与有机基体之间存在良好相容性,疏水纳米SiO2已成为一种广泛应用于有机材料中的重要无机纳米填料.介绍了纳米SiO2疏水改性的原理方法,综述了纳米SiO2疏水改性最新研究进展及其在硅橡胶、涂料、塑料、化妆品等领域的应用情况,并对今后的研究发展提出了建议.     

纳米SiO2增韧改性环氧树脂的研究

通过高剪切分散和催化剂的催化相结合的方法,使纳米SiO2粒子与环氧树脂发生化学键接,制得纳米SiO2改性环氧树脂.利用拉伸测试、扫描电子显微镜(SEM)、显微红外分析等手段对改性环氧树脂的性能和结构进行了研究.结果表明,纳米SiO2的化学改性在环氧树脂中引入了Si-O-C键,较大地提高了环氧树脂的拉伸强度、断裂伸长率,使环氧树脂柔韧性增强,且耐蚀性也有所提高.     

硅烷偶联剂改性纳米SiO_2的分散性能

用硅烷偶联剂KH-570对纳米SiO2进行表面改性,用红外光谱仪(IR)、热重(TA)、Zeta电位、SEM、性能测试等对改性纳米SiO2进行了研究,结果表明,偶联剂KH-570与SiO2化学结合形成了Si—O—Si键,其附着量约5.8%,结合溶剂水约10.35%;改性纳米SiO2在乙醇介质中的Zeta电位由-14.9 mV减小到-41.1mV,体系稳定性可达60 h以上;改性SiO2用作光固化牙科复合树脂的填料,分散性显著提高,其维氏硬度、压缩强度、弹性弯曲强度等性能提高10%以上。     

Structural and surface propperties of Ni-Cu nanoparticles supported on SiO2

Nickel (1%) and nickel (1%)-copper (0.2–0.75%) metal phases supported on silica have been prepared by aqueous hydrazine reduction of nickel acetate at 70°C. They were characterized by XRD, TEM, H₂-adsorption and TPD. The obtained results show that nickel is in a whisker-like shape or as a film of low density for the Ni/SiO₂ and Ni-Cu/SiO₂ systems respectively. The mean particle size is lower than 2 nm. Copper is in the shape of bigger facetted particles in the mono or bimetallic systems with a mean particle size of about 25 nm. The nickel phase dispersion, as determined by H₂-adsorption, decreased in the presence of copper, as probably a result of Ni-Cu interactions. All the solids were found to be good hydrogen reservoir through the formation of H-spiltover species. The amounts of hydrogen stored changed with the copper content due to changes in the Ni-Cu interactions.     

掺杂纳米SiO2粉末的微孔型聚合物电解质研究

用萃取法制备了偏二氟乙烯 六氟丙稀共聚物( P ( VdF HFP))为基质, 1mol/L 的 LiPF6/EC/DMC/DEC 溶液为液体电解质的微孔型聚合物电解质。测试结果表明:室温电导率最大值达 4.38×10-3S/cm;扫描电镜(SEM)和 X 射线衍射分析(XRD)结果表明电解质膜为非晶态的多孔结构;差示扫描(DSC)结果表明在-50~76℃温度范围内膜电解质膜为无定形态;其电化学稳定性窗口为5V。     

纳米铁粉吸波剂的表面改性及其分析表征

采用油酸和KH-560对纳米铁粉进行改性,通过红外光谱、热分析、透射电镜等方法对改性后粒子进行了表征和研究,结果表明,油酸对纳米铁粉的改性效果明显优于KH-560改性,而且油酸还有去除纳米铁粉表面氧化层的作用.     

Influence of surface modification by 2-aminothiophenol on optoelectronics properties of ZnO nanoparticles

In this study, a precipitation method was used to synthesise ZnO nanoparticles using suitable precursors. An efficient surface modification method was proposed in order to reduce the agglomeration among synthesised small sized ZnO nanoparticles using 2-aminothiophenol as a capping agent. This article briefly investigated the effects of capping agent like 2-aminothiophenol on the optoelectronic properties of ZnO nanoparticles. The modified effectivity of 2-aminothiophenol has been examined on the nanosized ZnO nanoparticle for fluorescence and UV–visible (UV–vis) studies. The mechanism was studied for ZnO nanoparticles light emitting capability under different conditions. By facilitating the capping of ZnO with 2-aminothiophenol, fluorescence emission of the surface defects vanishes and ultraviolet (UV) emission increases. Surface capping by 2-aminothiophenol effectively covers most of the surface defects of ZnO and results in quenching of the visible region. The UV–vis absorption spectra of modified ZnO nanoparticles has been influenced by modified ZnO nanoparticles as a result of surface modification; where marked blue shift in absorption edge results. By surface modification of ZnO nanoparticles, change in optoelectronics properties has opened the new scope and possibilities to explore and fine tune the optical character of the modified ZnO for various optoelectronics applications such as UV laser.     

纳米粒子的表面聚合物接枝改性

综述了纳米粒子与高分子聚合物复合的优点及不足,分析引起不足的原因,指出纳米粒子表面改性的重要性。同时在比较纳米粒子几种表面改性方法的基础上指出化学接枝改性的优越性,分析各种化学接枝改性方法及其有关的修饰机理和几种常用的表征方法。     

利用SiO2的表面化学修饰提高纳米SnO2的热稳定性

以3-氨丙基三乙氧基硅烷(3-APTES)为表面修饰剂,利用乙氧基与SnO2表面羟基之间的化学反应,将SiO2化学接枝于SnO2表面,以阻止SnO2晶粒热生长。采用SEM、TEM、FT-IR、XRD和EDS等技术对改性后纳米SnO2进行结构表征。结果表明,SiO2通过Sn—O—Si化学键与SnO2相连接,SiO2被高度分散于SnO2表面。经1000℃高温煅烧后,SnO2平均粒径改性前后分别为95和10nm。SiO2作为第二相,阻碍了晶界的移动,增加了晶粒生长活化能,从而有效地限制了晶粒高温生长,提高了纳米SnO2的热稳定性。     

A novel technology for powder dispersion and surface modification

A novel technology for powder dispersion and surface modification was studied by experiment in this paper. In the process, powders are dispersed by the nozzle and the atomized modifying agent is sprayed into the dispersed particles and coated on the surface at the same time. Silica, mica and talc powders were dispersed and modified by this technology, the performance of powder dispersion is evaluated by the scanning electron microscope (SEM), and the performance of surface modification is evaluated in advance by the viscosity of powder-paraffin suspension. In experiment, the modified silica was filled in the polypropylene (PP), the impact fractographs, notched impact and tensile properties of the PP composites were studied, the results indicate that the developed technology is effective for powders dispersion and surface modification.     

沉淀纳米SiO2的聚硅氧烷原位改性及应用研究

以聚醚改性羟基官能聚二甲基硅氧烷为改性剂,采用化学沉淀-原位改性法合成纳米SiO2.研究了聚硅氧烷原位改性对纳米SiO2特性的影响,并考察了其作为消光剂在醇酸清漆中的应用效果.结果表明,原位改性制得了粒径分布均匀、分散稳定性高的纳米SiO2,其在醇酸清漆中具有高的消光效率,同时能改善漆的透光度.