硅烷偶联剂表面改性二氧化钛粒子超疏水性能研究

针对无机二氧化钛（TiO2）粒子在有机体系中的分散性问题,采用硅烷偶联剂KH-570对无机填料钛白粉（二氧化钛,TiO2）的表面进行有机化改性;并通过红外光谱（FT-IR）、接触角测试、沉降实验、扫描电子显微镜（SEM）等手段表征表面改性TiO2粒子的结构,测试其超疏水性能,分析超疏水表面形成的机理。结果表明,经KH-570表面改性的TiO2粒子的疏水性和分散性得到明显改善,当KH-570质量分数达到15%时,表面改性的TiO2涂层与水的静态接触角达152.5˚,表现出良好的超疏水性能。     

硅烷偶联剂表面改性二氧化钛粒子超疏水性能

针对无机二氧化钛(TiO2)粒子在有机体系中的分散性问题,采用硅烷偶联剂KH-570对无机填料钛白粉(二氧化钛,TiO2)的表面进行有机化改性;并通过红外光谱(FTIR)、接触角测试、沉降实验、扫描电子显微镜(SEM)等手段表征表面改性TiO2粒子的结构,测试其超疏水性能,分析超疏水表面形成的机理。结果表明,经KH-570表面改性的TiO2粒子的疏水性和分散性得到明显改善,当KH-570质量分数达到15%时,表面改性的TiO2涂层与水的静态接触角达152.5°,表现出良好的超疏水性能。     

纳米二氧化钛/氧化锌超疏水涂层的制备及其性能

将纳米TiO2和微米ZnO机械搅拌,制备了纳米TiO2/ZnO复合粒子。通过硬脂酸对其改性,于200°C下烘烤15min,在钢试片上得到纳米TiO2/ZnO复合超疏水涂层。采用扫描电镜、红外光谱和接触角分析仪对涂层表面的形貌和疏水性进行了表征。结果表明,复合粒子经硬脂酸表面改性后引入了疏水性的甲基,形成微/纳米双重粗糙结构。当硬脂酸含量为9%时,所得涂层表面与水的静态接触角为165.3°,滚动角4°。该涂层具有优异的耐溶解性、耐温性及自清洁性。     

纳米二氧化钛改性及其在涂料中的应用

简要介绍了纳米二氧化钛表面改性的常用方法,并综述了纳米二氧化钛在抗菌涂料、净化空气涂料、汽车面漆、耐老化涂料等方面的应用进展。     

二氧化钛的有机表面改性

本文采用有机改性处理二氧化钛 ,首先对表面改性剂进行了筛选 ,然后对改性剂浓度、改性剂用量、改性时间、改性温度等工艺条件进行正交实验 ,得到最佳改性方案。     

纳米二氧化钛的表面改性研究

采用不同的表面活性剂三乙醇胺、十二烷基硫酸钠(SDS)、聚乙烯吡咯烷酮(PVP)对纳米二氧化钛进行表面改性处理。对不同表面活性剂处理的纳米二氧化钛采用沉降法来表征纳米粉体在水中的分散性,目的是日后用来制备更均匀的复合薄膜。研究结果表明:三乙醇胺与其他两种表面活性剂混合使用较单种表面活性剂处理后的纳米二氧化钛其分散效果会更好。分散纳米二氧化钛效果最佳的表面活性剂为三乙醇胺与十二烷基硫酸钠的混合物(质量比为2∶1),表面活性剂总用量为30%(质量分数),采用搅拌和超声时间都为15 min,纳米二氧化钛的初始沉降时间为2.5 h,完全沉降时间大于120 h。     

纳米二氧化钛的表面改性技术进展

纳米二氧化钛（TiO2）是一种用途广泛的无机材料,具有广泛的用途。介绍了纳米二氧化钛的表面性能以及表面改性技术进展,指出了其今后的发展方向。     

二氧化钛粉体的表面改性研究

针对二氧化钛和二氧化硅粉体的表面改性,研究了不同偶联剂种类、偶联剂含量和不同水解环境下粉体的改性效果.实验结果显示,对于不同种类偶联剂KH550、KH560、KH570改性二氧化钛,KH570改性的二氧化钛沉降体积最大,亲油化度也最大,改性效果较好.在中性预水解条件下偶联剂对二氧化钛粉体的改性效果均优于酸性和碱性条件....     

纳米二氧化钛的表面改性研究

初步研究了硬脂酸对纳米二氧化钛陶瓷粉体的表面改性作用及其对粉体极性和流动性的影响。实验结果表明 ,硬脂酸中的羧基与纳米二氧化钛粉体颗粒表面的羟基发生了类似于酸和醇的酯化反应 ,并在其表面形成单分子膜。经过表面改性的纳米二氧化钛由极性转化为非极性 ,同时表现出良好的流动性能     

用二氧化硅表面改性纳米二氧化钛的制备及表征

针对二氧化钛(TiO2纳米颗粒在水性涂料中极易团聚、分散性差的问题,以提高TiO2分散稳定性为目的,用并流中和法,以锐钛矿型纳米TiO2粉体为载体,硅酸钠(Na2SiO3)为包覆剂,用硫酸(H2SO4)调节pH值,成功地在纳米TiO2表面包覆致密的SiO2膜.借助Fourier变换红外光谱(Fourier transform infrared spectroscopy,FTIR)、X射线衍射技术(X-ray diffraction,XRD)和X射线能量散射谱(X-ray energy dispersive spectroscopy,EDS),表征样品的键合情况、相态结构、表面的化学成分,同时测定包覆改性前后的纳米TiO2比表面积和酸溶性.FTIR和EDS结果表明:该包覆方法可行,氧化硅(SiO2)以化学键合的方式沉积在纳米TiO2表面,在包覆层和纳米TiO2颗粒之间的界面上形成了Ti-O-Si键.酸溶实验分析和XRD结果证实:在TiO2纳米颗粒表面包覆了一层致密SiO2膜.比表面测定的结果显示:改性后TiO2的比表面积随质量分数m(SiO2):m(TiO2)增加而减小.     

CTAB对二硫化钼粉体的表面改性实验研究

二硫化钼(MoS2)具有层状结构,是聚合物基复合材料常用的无机填料.作者以十六烷基三甲基溴化铵(CTAB)对MoS2粉体进行表面改性,改性后的MoS2粉体在非极性溶剂中的分散性提高,悬浮液的浊度从215提高到345,活化指数从0.42提高到0.82,吸油量降低,透水时间明显延长,结果表明:改性后的MoS2粉体亲油性提高;同时采用FT-IR及XRD对改性前后的MoS2粉体进行了结构表征,分析表明改性后的MoS2粉体粒子表面成功地被CTAB包覆,通过改性MoS2填充型聚苯硫醚(PPS)/聚丙烯(PP)复合材料成型样条的断口SEM表征,结果表明改性MOS2粉体能够在聚合物基体中均匀分散.     

Organic modification of ultrafine particles using carbon dioxide as the solvent

An organic modification of the surface of titanium dioxide particles precoated with SiO₂ and Al₂O₃ films in a CO₂ medium is performed, where CO₂ of different phases is used as the solvent and a titanate coupling reagent (CH₃)₂CHOTi(OP(O)(OH)OP(O)(OC₈H₁₇)₂)₃ is the modification reagent. The results are compared with the modification carried out in a conventional organic solvent. The interaction between the functional groups of the modification reagent and the hydroxyl groups on the surface of the particles is analyzed. Experimental results indicate that the surface of particles is modified efficiently when the CO₂ solvent is in a supercritical or liquid state. The particles are remarkably changed from hydrophilic to hydrophobic by the modification. A chemical bond of AlOTi is likely formed between the molecules of the organic modification reagent (CH₃)₂CHOTi(OP(O)(OH)OP(O)(OC₈H₁₇)₂)₃ and the particle surface. The actual maximum quantity order of organic modification reagent reacted on the particle surface is about 7.08×10⁻⁷ mol/m² (1.73% by weight) from thermogravimetric analysis. The organic modification process using supercritical or liquid CO₂ as the solvent has the advantages of being simple, effective, and green.     

Preparation and characterization of high-surface-area titanium dioxide by sol-gel process

One of the important ways to improve photocatalytic efficiency is to prepare catalyst with enhanced surface area. In this work, titanium dioxide (TiO₂) nanoparticles having enhanced surface area were synthesized under the interference of SiO₂. The mixed oxide, SiO₂-TiO₂ (10% mol% Si), was prepared by a sol-gel procedure using titanium tetra-n-butoxide as Ti-precursor. The commercial SiO₂ nanoparticles were added into the TiO₂ sols after hydrolysis. After condensation and calcination heat treatment, the SiO₂-TiO₂ nanoparticles were obtained. To achieve the purpose of obtaining the high-surface-area TiO₂, the SiO₂ was removed subsequently by aqueous NaOH solution. The TiO₂ products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), electron spectroscopy for chemical analysis (ESCA), and by N₂ adsorption-desorption isotherm. A fine mesoporous structure was formed for as-prepared TiO₂ after calcination at 400^∘C and the average pore diameter was about 7 nm. The porous TiO₂ products possess mixing phases of anatase and rutile. Phase transformation from anatase to rutile occurred when the samples were calcined. The phase transition temperature is sensitive to the silicon content. The particle size of ∼43 nm remained constant upon calcinations from 500 to 700^∘C. The specific surface area was increased up to 66% compared to regular TiO₂ samples that were prepared by the similar sol-gel procedure. The porous TiO₂ nanostructures exhibited enhanced photocatalytic performance to decompose methylene blue under UV irradiation.     

Surface modification of titanium dioxide for electrophoretic particles

To prepare stable electrophoretic ink (E Ink) needs color particles to be uniformly dispersed in the organic medium. Thus, t-he modification of inorganic particle surface is required. In this paper, Titanium dioxide modified by alumina has been studied. The surface composition and structures of modified particles have been characterized by X-ray photoelectron spectrometer (XPS), X-ray diffractometer (XRD) and Fourier transform infrared spectrometer (FT-IR). The dispersibility and electrophoretic mobility of these particles in tetrachloroethylene (TCE) have been investigated by laser particle size analyzer, static sedimentation and electrophoretic instrument. Effects of temperature, pH value and stirring rate on the dispersibility and the charge property of samples have been discussed. The results indicate the settle time of modified TiO₂ can last 120 h with the response time of 35 s under the optimized modifying conditions, in which temperature is 85°C–90°C, pH is 8–9 and stirring rate is 800 r·min⁻¹. The dispersibility and electrophoretic mobility have been significantly improved, which means that the modified TiO₂ is suitable for electrophoretic ink particles. __________ Translated from Journal of Chemical Engineering of Chinese Universities, 2006, 20(6): 893–897 [译自: 高校化学工程学报]     

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     

Surface energy measurements of coated titanium dioxide pigment

In this study surface energy measurements have been carried out on titanium dioxide pigments coated with different types of organic compounds. The organic coatings investigated were polymethylsiloxane and octyl triethoxy-silane. The level of coating applied was increased from 0.2 up to 1.5 wt%. Contact angles were measured using an advancing sessile drop method. To allow for the fact that measurements were made on pressed discs of particles rather than on a perfectly flat surface, a correction was applied to convert each measured contact angle to the true Young's contact angle. Surface energies were calculated from the corrected contact angles using the Owens and Wendt equation. From the values of surface energy it was possible to determine at what coating level the surface characteristics changed from hydrophilic to hydrophobic and hence when complete coverage had taken place. For both the siloxane and the silane coatings it was found that complete coating coverage occurred at an addition level of around 0.8 wt%. The surface energies of all the coated pigments were found to correlate well with their dispersion behaviour in liquid paraffin.     

硅烷偶联剂水解及对钛白粉的改性研究

通过电导率对乙烯基三乙氧基硅烷偶联剂（A-151）的水解行为进行研究,考察了pH、水与A-151体积比和温度对硅烷水解行为的影响,利用A-151的水解特性,对经锆铝二元包覆后的钛白粉进行表面改性,并采用表面接触角测试仪、红外光谱和扫描电镜对有机改性后的二氧化钛进行表征。表面接触角测试显示改性后的二氧化钛制片表面润湿角达108.2°;改性后的粉体在波数为3 078 cm-1处出现了对应的烯烃C-H伸缩振动吸收峰;扫描电镜照片显示改性后的二氧化钛粒子的分散性得到了改善。     

Interactions of Polyacrylamide with Cationic Surfactants: Thermodynamic and Surface Parameters

The aggregation behaviour of two cationic surfactants, viz. cetyl trimethyl ammonium bromide (CTAB) and N-cetyl pyridinium chloride (CPC), in different concentrations of water-soluble polyacrylamide has been studied in alkaline medium by electrical conductivity and surface tension measurements. A decrease in the critical micelle concentration (CMC) of the surfactant with an increase in polymer content in the mixture was observed. The thermodynamic and surface parameters have been determined and discussed. The results indicate that micellisation becomes more favourable at higher polymer content.     

Atmospheric pressure plasma surface modification of titanium for high temperature adhesive bonding

In this investigation surface treatment of titanium is carried out by plasma ion implantation under atmospheric pressure plasma in order to increase the adhesive bond strength. Prior to the plasma treatment, titanium surfaces were mechanically treated by sand blasting. It is observed that the contact angle of de-ionized water decreases with the grit blast treatment time. Optical microscopy and scanning electron microscopic (SEM) analysis of untreated and atmospheric plasma treated titanium are carried out to examine the surface characteristics. A substantial improvement in the surface energy of titanium is observed after the atmospheric pressure plasma treatment. The surface energy increases with increasing exposure time of atmospheric pressure plasma. The optimized time of plasma treatment suggested in this investigation results in maximum adhesive bond strength of the titanium. Unmodified and surface modified titanium sheets by atmospheric pressure plasma were adhesively bonded by high temperature resistant polyimide adhesive. The glass transition temperature of this adhesive is 310 °C and these adhesively bonded joints were cured at high temperature. A substantial improvement in adhesive bond strength was observed after atmospheric pressure plasma treatment.     

Photodegradation of benzothiazole ionic liquids catalyzed by titanium dioxide and silver-loaded titanium dioxide

In recent years, ionic liquids(ILs) have been widely used in extraction, synthesis, electrochemistry and other fields.Meanwhile, the environmental impact of ILs has been attracting a lot of attention, and eco-friendly treatment for ILs is becoming a necessary subject. In this study, photocatalytic degradations of benzothiazole ILs catalyzed by titanium dioxide(TiO_2) and silver-loaded titanium dioxide(Ag/TiO_2) were studied for the first time. The degradation of benzothiazole hexafluorophosphate([C4 Bth]PF6) could reach more than 99% within 240 min with the catalysis of TiO_2. To improve catalytic efficiency, Ag/TiO_2 was synthesized and characterized by UV–Vis diffuse reflectance absorption spectra(DRS) and X-ray photoelectron spectroscopy(XPS). The degradation of [C4 Bth]PF6 could reach more than 99% within 120 min in the degradation catalyzed by Ag/TiO_2. The photodegradation products of benzothiazole ILs are composed of inorganic substances or organic substances with simpler structures, which are easier to decompose and less toxic. The degradation system proposed by this study could provide a simple, green,safe, and economical method for the efficient treatment of benzothiazole ILs.