碱式碳酸镁的表面有机改性及性能表征

利用湿法工艺改性碱式碳酸镁,研究了改性剂种类及用量、料浆浓度、改性温度和时间对接触角和活化指数的影响。借助接触角测量仪、X射线衍射仪、红外光谱、热重分析和扫描电子显微镜表征改性前后碱式碳酸镁的性能。结果表明:适宜的改性剂为硬脂酸钠,最佳改性工艺为料浆浓度50 g/L,改性剂用量4%(占碱式碳酸镁粉末的质量),改性温度75℃,改性时间50 min。在最佳条件下,改性粉体的接触角为130.9°,活化指数为99.97%。表面改性过程对碱式碳酸镁的物相组成、化学结构、热分解和形貌没有明显影响。硬脂酸钠改性碱式碳酸镁的实质主要是硬脂酸钠中亲固基与碱式碳酸镁表面发生物理吸附,其疏水基朝外,从而使得碱式碳酸镁表面由亲水性变为疏水性。     

沉降速度表征氢氧化镁阻燃剂改性效果的研究

在改性研究中,通过沉降速度对改性前后的氢氧化镁粉体进行表征和测试,以确定最佳的表面改性剂和最佳的改性工艺条件。研究结果表明最佳的表面改性剂为硬脂酸锌;最佳的改性工艺条件为:改性温度为85℃,改性剂用量为5%,改性时间为0.5h。     

碳酸钙晶须表面改性研究

采用几种改性剂对碳酸钙晶须进行了表面改性试验,结果表明硬脂酸钠对碳酸钙晶须的改性效果显著,以硬脂酸钠为改性剂,考察了改性剂用量、改性时间、改性温度、初始料浆质量分数、搅拌速度、烘干温度等因素对碳酸钙晶须表面改性的影响,选择活化指数及接触角对碳酸钙晶须的改性效果进行表征,在最佳试验条件下,改性产品的活化指数为100%,接触角为146.66°.碳酸钙晶须改性前后的IR检测分析表明,硬脂酸钠改性碳酸钙晶须过程中,在硬脂酸钠与碳酸钙晶须间存在化学吸附.     

氢氧化铝阻燃剂的表面改性研究

通过硬脂酸对氢氧化铝阻燃剂的表面改性研究,探讨了硬脂酸用量、时间、温度等工艺因素。氢氧化铝改性的影响。结果表明,最佳的改性条件为改性剂用量为氢氧化铝质量的3％：改性时间和温．分别为30min和90℃。通过粘度测试、热重分析（TG）和傅立叶变换红外光谱分析（FT—IR）测试与分析,结果表明：改性的氢氧化铝与石蜡相容性增大;改性剂和氢氧化铝之间存在化学键合,形成了化学键。     

氢氧化镁粉体的表面改性研究

主要研究了氢氧化镁的湿法表面改性的工艺过程，用浊度分析方法对改性效果进行了比较，确定了最佳工艺条件。实验结果表明：最佳改性剂为硬脂酸钠，改性剂用量为6％（质量分数），改性温度为85℃，改性时间为20min。同时，最佳条件下改性样品的红外光谱分析表明：最佳改性条件下，硬脂酸钠有效包覆在氢氧化镁粒子表面，使氢氧化镁表面有机化，增强了氢氧化镁粉体与有机体的亲和性，这对于制取添加型的氢氧化镁阻燃剂具有指导意义。     

硅灰石表面改性

南粒度、SEM和长径比分析得出“气流磨”是硅灰石超细粉碎的最佳设备。对超细硅灰石粉体进行了表面化学改性．确定最佳工艺条件：改性剂为硬脂酸，改性剂用量2％．改性时间15～20min．改性温度70℃。探讨了超细改性硅灰石在橡胶中的应用。     

硬脂酸对碳酸钙表面改性的研究

采用硬脂酸对碳酸钙进行表面改性,研究了改性剂用量、改性温度和改性时间对改性效果的影响。测定了改性前后碳酸钙沉降体积、吸油值、活化度和黏度,并用红外光谱进行表征。实验结果表明硬脂酸可以改性碳酸钙,其改性较佳条件:硬脂酸用量为2.5%,改性温度85℃,改性时间50min。     

纳米水滑石的表面改性研究

采用二硬脂酸铝湿法改性纳米水滑石,以活化指数和接触角作为水滑石改性效果的评价指标,分别研究改性温度、改性时间、改性剂用量、初始料浆质量分数等因素对水滑石表面改性效果的影响,并采用FE-SEM、XRD和FT-IR对改性水滑石进行表征。结果表明:改性温度为80℃,改性时间为60min,改性剂用量为4%,初始料浆质量分数为5%时,改性效果最好,改性后纳米水滑石的活化指数和接触角分别达到100%和135°;水滑石经二硬脂酸铝改性后分散性得到提高,且改性剂未破坏水滑石的晶体结构,改性后二硬脂酸铝与水滑石表面既存在化学吸附又存在物理吸附,但主要以化学吸附为主。     

超细粉碎硅灰石的表面改性及在橡胶中的应用

由粒度、SEM和长径比分析得出"气流磨"是硅灰石超细粉碎的最佳设备.通过对超细硅灰石粉体的表面化学改性效果的研究,确定了最佳工艺条件:改性剂为硬脂酸,改性剂用量2%,改性时间15～20min,改性温度70℃.并探讨了超细改性硅灰石在橡胶中的应用.     

页岩提钒中和渣制备硫酸钙晶须填料的研究

以页岩提钒中和渣为原料,采用水热法制备硫酸钙晶须,并进行稳定-改性处理,最终制备用于填充塑料的硫酸钙晶须填料。研究了反应温度、反应时间、料浆浓度及助晶剂用量对硫酸钙晶须长径比的影响以及改性剂用量、初始料浆浓度、改性温度及改性时间对硫酸钙晶须改性效果的影响。结果表明,在反应温度为130℃、反应时间为6 h、料浆质量分数为3%、助晶剂六水氯化镁用量为10%的条件下,制备出的硫酸钙晶须长径比达90,但晶须在空气中易水化变粗,长径比降至20以下。在硬脂酸用量为4%、初始料浆质量分数为8%、改性温度为90℃、改性时间为20 min的条件下,制备的硫酸钙晶须填料活性指数达0.72,吸油值为0.278 8 g/g,制得的硫酸钙晶须填料呈棒状或纤维状,表面光滑,结晶度较好,长径比稳定在40~50。结合XRD、SEM、FT-IR分析可知,硬脂酸能有效抑制晶须水化过程,保持晶须晶型及形貌稳定,硬脂酸通过与晶须表面发生化学键链接封闭其亲水活性点而抑制晶须水化。     

抗紫外纳米ZnO粉体的表面改性与脂肪酸改性机理探讨

叙述了无机纳米 Zn O抗紫外剂的优良性能 ,纳米 Zn O的表面改性。用多种表征手段对所改性的粉体性质进行了性能测试 ,并初步探讨了脂肪酸对纳米 Zn O的改性机理。所制的纳米 Zn O粒度均匀 ,分散性好 ,紫外吸收能力可与进口的纳米 Zn O粉体相媲美。适用于化妆品、涂料、塑料和橡胶等的抗紫外线     

Pyrene‐anchored ZnO nanoparticles through click reaction for the development of antimicrobial and fluorescent polyurethane nanocomposite

This work demonstrates the development of a multifunctional, antimicrobial and fluorescent polyurethane–ZnO hybrid nanocomposite coating with the aid of azide–alkyne click chemistry. Firstly, the surface of ZnO nanoparticles was successfully modified with 3‐azidopropyltriethoxysilane coupling agent. The azide‐terminated nanoparticles were then reacted with separately synthesized propargylpyrene in order to obtain pyrene‐anchored ZnO nanoparticles. The size of the modified nanoparticles was measured using dynamic light scattering and field emission scanning electron microscopy. Thermogravimetric analysis showed that the thermal stability of the nanoparticles decreased with surface modification. The intensities of UV absorption and fluorescence emission were improved with an increase of pyrene units on the ZnO surface. These nanoparticles were incorporated into a triazole‐rich hyperbranched polyurethane matrix in various weight percentages. It was observed that thermal stability and the intensity of UV absorption and fluorescence emission of the resulting polyurethane nanocomposite hybrid films were improved with loading of the modified nanoparticles. These hybrids are extremely resistant towards various bacterial and fungal attacks, which is attributed to the presence of the ZnO nanoparticles in the coatings. © 2014 Society of Chemical Industry     

抗紫外纳米ZnO粉体的制备与表面改性

叙述了无机纳米ZnO的制备与表面改性及其抗紫外的优良性能,并用多种表征手段对所制备并经改性的粉体性质进行了性能测试,所制得的纳米ZnO粒度均匀,分散性好,紫外吸收能力可与进口的粉体相媲美,适用于化妆品、涂料、塑料橡胶等作抗紫外剂。     

Photocatalytic Silver Recovery Using ZnO Nanopowders Synthesized by Modified Glycine-Nitrate Process

Zinc oxide (ZnO) powders were synthesized by the modified glycine-nitrate process (MGNP) with various oxidants and fuels. Single-phase ZnO powders were easily obtained regardless of oxidants and fuels. The particle size and shape of ZnO powders were dependent on the types of fuels. The ZnO powder synthesized using Zn(OH)₂ and glycine as an oxidant and a fuel, at a fuel/oxidant ratio of 0.8, showed the best powder characteristics, such as an average grain size of 30 nm and the specific surface area of 120 m²/g. The removal of silver ions from the waste-development solution was tried to confirm photocatalytic activities of the synthesized ZnO powder. The silver ions were completely removed within 15 min. This silver recovery rate is three times higher than that of commercial state-of-the-art TiO₂. The photoluminescence (PL) measurement also showed the PL intensity at ultraviolet (UV) of the synthesized ZnO powder is almost three times higher than that of commercial state-of-the-art TiO₂. The synthesized ZnO nanopowder absorbed more UV than any other powders, including commercial state-of-the-art TiO₂ and ZnO powders. This means the high UV absorption efficiency leads to the generation of more electrons that are involved in the reduction of silver ions.     

氧化锌晶须表面改性及表征

采用湿法表面化学改性法，用硅烷和钛酸酯偶联剂对氧化锌晶须(ZnOw)进行了表面改性；考察了溶剂、pH值、温度及分散时间对硅烷类偶联剂改性效果的影响，采用活化指数、接触角以及傅立叶变换红外光谱对改性结果作了表征。同时将改性后的ZnOw填充到线性低密度聚乙烯(LLDPE)中，测试了复合材料的机械性能。实验结果表明，硅烷和钛酸酯偶联剂均能用于ZnOw的表面改性，其最佳改性条件不同，获得最佳改性效果的偶联剂用量也不同。经ND-42改性的ZnOw填充到LLDPE中，复合材料的弯曲强度大幅度提高。     

主链含亲水基团的聚氨酯/改性纳米ZnO复合膜的制备与性能

以异佛尔酮二异氰酸酯(IPDI)、聚酯二元醇、二羟甲基丙酸(DMPA)、硅烷偶联剂改性纳米ZnO等为原料,通过阴离子自乳化法制备了一系列聚氨酯/改性纳米ZnO复合膜。主要研究了纳米ZnO含量对复合膜的力学性能、耐摩擦性能和耐水性能的影响。结果表明:当偶联剂用量为5%、反应温度为70℃、搅拌时间为2h时,纳米ZnO改性效果最好;当改性纳米ZnO含量为0.5%时,复合膜具有良好的综合性能。     

Reducing the Photocatalytic Activity of Zinc Oxide Quantum Dots by Surface Modification

The use of zinc oxide (ZnO) nanoparticles as ultraviolet (UV) absorbers for many organic substrates is limited because of the high photocatalytic activity of ZnO. In this study, a facile and efficient technique for the preparation of a hybrid material of silica-coated ZnO nanoparticles was used to reduce the photocatalytic activity of ZnO. Monodispersed ZnO nanopartcles were prepared by wet chemistry and the particle surface was modified by tetraethylorthosilicate to form a silica coating via the Stöber method. ZnO samples, both before and after the coating process, were investigated by transmission electron microscopy, X-ray diffraction, dynamic light scanning, infrared, and UV-Vis absorption spectroscopy. The effect of the surface modification on the photocatalytic activity of ZnO was studied by monitoring the degradation of Rhodamine B caused by photo-generated free radicals. The results implied that the photo-generation of free-radicals was strongly quenched by the presence of silica on the particle surface.     

纳米氧化锌表面修饰及其应用研究进展

纳米氧化锌（ZnO）是一种广泛使用的多功能材料。本文介绍了ZnO的性质和应用,并阐述了表面修饰的重要性。表面修饰会引起ZnO粒径、缺陷和表面化学性质变化。在对表面修饰方法作简单分类后,结合应用综述了表面修饰对ZnO光学性质、抗菌性、生物毒性以及对ZnO/聚合物纳米复合材料性质的影响,并从不同角度分析其原因。适当的表面修饰可提高ZnO的稳定性和分散性,增强其抗紫外、光催化、光致发光和抗菌性质,降低其毒性,并能调控和协调其性质,而不当的表面修饰会导致ZnO性质劣化。然而,要全面和准确地预测并实现表面修饰的优势效果仍面临较大挑战。在表面修饰剂和表面修饰方法的选择、表面修饰剂体系的建立、表面修饰机理及性能优化等方面还需要更深入系统的研究。     

纳米氧化锌的气流粉碎改性研究

以硅烷偶联剂为改性剂,在气流粉碎机中对纳米氧化锌进行解团聚和表面改性,并借助SEM、XRD、FT-IR对改性前后的纳米氧化锌粉体进行结构表征。结果表明,与改性前相比,改性纳米氧化锌的二次粒径明显减小,解团聚效果明显;颗粒表面亲油疏水,在有机溶剂中有较好的分散性。     

A study of photoluminescence properties and performance improvement of Cd-doped ZnO quantum dots prepared by the sol-gel method

ABSTRACT: In the present work, ZnO quantum dots (QDs) have been prepared by the sol-gel method, and the performance of the QDs have been improved. The effect of Cd concentration on the structural and luminescent properties of the QDs, as well as the effect of the mass ratio of trioctylphosphine oxide (TOPO)/octadecylamine (ODA), has been investigated. The ZnO and Cd-doped ZnO QDs have hexagonal wurtzite structures and are 3~6 nm in diameter. When the Cd content was increased, the QD particle size was reduced; this effect was confirmed in the corresponding ultraviolet-visible (UV) spectra. The fluorescence intensity was simultaneously enhanced significantly. Both the UV and fluorescence spectra were blue-shifted. The luminous intensity was further enhanced when the QDs were modified with TOPO/ODA. FTIR and XRD techniques proved that the polymer successfully coated the surfaces of the QDs. A TOPO/ODA mass ratio of 1:2 was determined to result in the best optical performance among the different ratios examined. The results showed that the described synthetic method is appropriate for the preparation of doped QDs with a high fluorescence quantum efficiency.