利用硬脂酸改性中铬黄颜料的效果和机理

选用硬脂酸对中铬黄颜料进行表面改性,对硬脂酸改性中铬黄的工艺优化和机理进行研究。结果表明:随着硬脂酸用量的增加,中铬黄的吸油量从0.22 g/g逐渐减小至0.15 g/g,减小了约30%,沉降时间由原来的1 h逐渐增加到28 h,流动性没有得到改善,硬脂酸质量分数为2.5%~3.5%时改性效果最优;改性中铬黄在干燥状态下分散性得到明显提高;硬脂酸通过—COO-键吸附Pb Cr O4中的Pb2+实现对中铬黄的表面改性。     

铝粉颜料的改性研究

主要研究了采用偶联剂为改性剂处理铝粉颜料,以满足其在水性涂料中稳定性的要求。选用4种不同的偶联剂改性处理,通过比较改性后样品在水溶液中的分散性得出,γ-APS硅烷偶联剂为较好的改性剂,且当偶联剂：水：乙醇质量比为1：2：30时,zeta电位值最大,处理过的铝粉颜料在水溶液中的分散性最好。通过EDS能谱研究了反应机理,可知硅烷偶联剂在铝粉颗粒表面发生缩聚反应,在铝粉颜料表面形成膜层,提高了铝粉颜料的耐腐蚀性。     

纳米沉淀二氧化硅的硅烷偶联剂原位表面改性

在沉淀二氧化硅的制备过程中,表面活性剂可以起到提高粒子分散性的作用.通过在沉淀二氧化硅制备过程中加入硅烷偶联剂,研究了硅烷偶联剂原位表面改性对沉淀二氧化硅性质的影响,并通过SEM、FTIR等分析手段对改性机理进行了分析.结果表明,当硅烷偶联剂(牌号为SCA-1613)的用量达到沉淀二氧化硅质量的6.0%时,制备得到的沉淀二氧化硅的物化指标明显改善.制得的样品白度97.1,比表面积223m2/g,吸油率为2.42ml/g,堆积密度为0.23g/ml.对改性前后的样品的SEM和FTIR分析表明,制得的沉淀二氧化硅原级粒度为纳米级,经过原位改性处理后,其团聚现象明显改善.FTIR分析表明,用硅烷偶联剂SCA-1613对沉淀二氧化硅在制备过程中进行表面改性时,改性剂分子吸附在二氧化硅颗粒的表面并与其形成化学键合.     

Preparation and characterization of nano-ZnO modified hv acetic ether

利用乙酸乙酯作为改性剂,通过气相法对纳米氧化锌进行改性研究,用亲油化度考察改性效果;优化其改性工艺为:改性时间2h,改性温度120℃,改性剂的添加量为3.25％.通过透射电镜、激光粒度仪、接触角和沉降实验表明,改性后的纳米氧化锌颗粒均匀、团聚明显减弱、疏水性和分散性明显提高.     

乙酸乙酯改性纳米氧化锌的制备及表征

利用乙酸乙酯作为改性剂,通过气相法对纳米氧化锌进行改性研究,用亲油化度考察改性效果;优化其改性工艺为:改性时间2h,改性温度120℃,改性剂的添加量为3.25%。通过透射电镜、激光粒度仪、接触角和沉降实验表明,改性后的纳米氧化锌颗粒均匀、团聚明显减弱、疏水性和分散性明显提高。     

硅灰石表面有机改性及对颗粒分散性的影响

为降低硅灰石颗粒表面的亲水性,改善其在有机介质中的分散性和界面结合作用,采用硬脂酸钠为改性剂对硅灰石进行表面改性,对改性工艺各影响因素进行试验考查,对改性后硅灰石表面润湿性和在有机介质中的分散性进行表征。结果表明:硅灰石经硬脂酸钠改性后,在水中的润湿接触角由改性前的10.83°增大为69.33°,表面自由能由102.17 m J/m~2减小至41.78 m J/m~2,改性硅灰石在煤油中的分散性显著提高,通过热力学分析解释改性前后硅灰石颗粒分散性变化的趋势。     

超细颗粒的气流强湍流分散与表面改性处理技术

对超细颗粒的气流强湍流分散与表面改性处理技术进行实验研究,通过气流强湍流对超细颗粒进行分散处理,然后将雾化的改性剂喷入已分散的颗粒体系中,进行颗粒的表面改性.文中研究了颗粒分散处理过程中不同喷嘴对分散效果的影响,以及颗粒表面改性处理过程中的工艺参数:改性温度、改性剂用量和改性剂种类对改性效果的影响,并将改性后的颗粒填充聚丙烯,通过实际应用效果来评价本文提出的颗粒分散与表面改性处理技术,结果表明,该技术能够有效地对颗粒进行分散与表面改性处理.     

改性纳米氢氧化镁的制备与表征

采用易于工业化的液相沉淀法,在石油磺酸盐的作用下,合成改性纳米氢氧化镁。通过沉降体积实验确定改性剂的最佳用量为0.2%(质量分数)。通过X射线衍射(XRD)、透射电镜(TEM)、N2吸附、堆密度分析等手段对改性前后样品进行表征分析。结果表明:改性后样品分散性好,结晶度高。红外光谱(FT-IR)和沉降实验结果表明:该方法可以使改性剂吸附在氢氧化镁颗粒表面,使氢氧化镁表面由亲水性变成亲油性,可提高氢氧化镁在有机介质中的分散稳定性。     

无机颜料的分散及其分散剂

无机颜料在涂料中的分散取决于颜料的本性和漆料的生产工艺。一般认为颜料在漆料中的分散过程,大致分为润湿、分散、稳定三个阶段。经过这三个阶段,能足以保证颜料在漆料中形成稳定的分散体系,涂装后能增加涂层的遮盖力和着色力。涂料生产中,无机颜料占有相当大的比重。与有机颜料相比,无机颜料的颗粒较大;极性强弱不均,使得在涂料中的润湿、分散及稳定程度要比有机涂料差些。因此,无机颜料的分散性是直接构成涂料质量优劣的十分重要的因素。一、无机颜料的分散性目前,涂料中多使用锌白、钛白粉、氧化铁、碳酸钙、硫酸钡、铬黄等氧化物和不溶于水的无机盐。无机颜料的表面极易吸收水,通常在粒子的外围有着一层水分子,使颜料的固体颗粒形成聚集体或互相隔离的屏障。为了消除屏障,促进颗粒分散,在涂料制造过程中必须向漆料中加入一些离子型的表面活性剂或分散剂。由于离子型表面活性剂,能有选择地     

含氮长链硼酸酯偶联剂改性阻燃水镁石

用自制的含氮长链硼酸酯偶联剂对水镁石粉体进行表面改性,利用红外光谱、X射线衍射和扫描电镜对改性前后的水镁石粉体进行表征。结果表明,经过改性的水镁石粉体的活化指数可达96.7%,吸油值从未改性前的1.190 40 mL/g减小为0.392 90 mL/g;经硼酸酯偶联剂改性后,水镁石粒子表面极性降低,分散性提高,同时偶联剂吸附在水镁石颗粒表面。     

纳米ATO在有机单体介质中的表面改性及分散研究

选用了多种改性剂,用超声波为分散手段,将纳米ATO粉体在有机单体介质中进行表面改性和分散,研究了改性剂种类、改性剂用量、改性时间、超声波输出功率和超声波处理时间等对纳米ATO-单体分散液稳定性的影响,探讨了纳米ATO表面改性机理.结果表明,硅烷偶联剂KH-570是纳米ATO的最佳改性剂,当其用量为纳米ATO的15%(质量分数),改性时间为24h,超声波输出功率为90%,超声波处理时间为12min时,纳米ATO-单体分散液具有最佳的分散稳定性.KH-570主要通过在纳米ATO表面水解产生硅羟基的自缩合,形成包覆改性.     

Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of synchrotron X-ray spectromicroscopy and related methods. 1. Artificially aged model samples

On several paintings by artists of the end of the 19th century and the beginning of the 20th Century a darkening of the original yellow areas, painted with the chrome yellow pigment (PbCrO(4), PbCrO(4)·xPbSO(4), or PbCrO(4)·xPbO) is observed. The most famous of these are the various Sunflowers paintings Vincent van Gogh made during his career. In the first part of this work, we attempt to elucidate the degradation process of chrome yellow by studying artificially aged model samples. In view of the very thin (1-3 μm) alteration layers that are formed, high lateral resolution spectroscopic methods such as microscopic X-ray absorption near edge (μ-XANES), X-ray fluorescence spectrometry (μ-XRF), and electron energy loss spectrometry (EELS) were employed. Some of these use synchrotron radiation (SR). Additionally, microscopic SR X-ray diffraction (SR μ-XRD), μ-Raman, and mid-FTIR spectroscopy were employed to completely characterize the samples. The formation of Cr(III) compounds at the surface of the chrome yellow paint layers is particularly observed in one aged model sample taken from a historic paint tube (ca. 1914). About two-thirds of the chromium that is present at the surface has reduced from the hexavalent to the trivalent state. The EELS and μ-XANES spectra are consistent with the presence of Cr(2)O(3)·2H(2)O (viridian). Moreover, as demonstrated by μ-XANES, the presence of another Cr(III) compound, such as either Cr(2)(SO(4))(3)·H(2)O or (CH(3)CO(2))(7)Cr(3)(OH)(2) [chromium(III) acetate hydroxide], is likely.     

表面交联对高吸水性树脂吸水性能的影响

采用异氰酸酯、醛及金属盐等对溶液聚合法制备的丙烯酸型吸水性树脂进行表面交联处理,结果表明以甲醛为表面交联剂处理后的树脂吸水速度快,入水后即分散、不结团,吸水凝胶表面干爽,加压下吸水性能好,且处理工艺简单,5g吸水树脂用0.1g左右的甲醛在室温下共置12h后即可得到综合性能优良的吸水树脂。     

The influence of stearic acid coating on the properties of magnesium hydroxide,hydromagnesite, and hydrotalcite powders

Hydrated filler-type flame retardants were coated with approximately a monolayer of stearic acid using a solvent technique. Compared to the uncoated powders, the BET surface area was lower, the powder packing density was improved, and the thickening effect on white oil was significantly reduced. The latter two observations are rationalized in terms of a reduction in the attractive interactions between the powder particles. The viscosity of white oil slurries containing 25 wt% solids showed shear-thinning non-Newtonian behavior. The coated powders showed significantly lower viscosities at low shear rates although the difference diminished at high shear rates. The lower viscosities shown by the coated powders indicate that the surface modification facilitated the break-up of agglomerates and the dispersion of individual particles in the fluid.     

Mechanochemical Dispersion of Nanodiamond Aggregates in Aqueous Media

A technology of mechanochemical treatment (MCT) is introduced to modify nanodiamond (ND) surface aiming to obtaining a stable suspension with well-dispersed ND particles in aqueous medium. ND investigated in this paper is a purified product of nanometer-sized diamond synthesized by explosive detonation. As obvious aggregation and sediment were observed when the sample was added into deionized water, it is crucial to conduct deaggregation and dispersion investigations. Amid a series of mechanical treatments, i.e. grinding, stirring, ultrasonic and classification, some reagents are introduced to modify the newly created surface during aggregates comminution. For the co-effects of mechanical forces and surfactants, the mean size of particles was reduced and a stable system containing ND with narrow size distribution was prepared. Mechanism of surface reaction and modification are discussed, while AFM, Zetasizer3000HS, XRD, XPS and FTIR are utilized for the analysis. The functional chemical structure of ND p     

水介质中纳米金刚石表面改性研究

对纳米金刚石在水介质中的分散进行了探讨,利用机械力和化学力共同作用,对纳米金刚石表面进行改性,从而实现纳米金刚石在水介质中的分散和稳定,采用不同的机械化学处理工艺,可以使得体系在酸性和碱性介质条件下均保护良好的分散。对表面改性过程进行了机理分析。     

新型水基磁流体的制备及其生物磁热效应研究

以化学共沉淀法合成出Fe3O4纳米超顺磁性颗粒,并首次采用泛酸(D-pantothenic acid)对粒子进行表面化学修饰,制备出稳定分散在水中的水基磁流体.通过TEM对磁流体表征显示,随着纳米Fe3O4颗粒表面改性泛酸分子的增加,磁流体分散状况显著改善.FT-IR光谱表明泛酸分子与纳米Fe3O4表面羟基发生化学键合;并分别用XRD、TG对水基磁流体进行表征,同时对其在交变磁场中的热效应进行了研究,产热比功率高达146.64W/g,在肿瘤磁热疗方面具有较大应用前景.     

表面改性剂对碳酸钙基复合白色颜料性能影响研究

本文通过活化一复合两步法制备碳酸钙基复合白色颜料粉体。研究了不同表面改性剂对颜料性能的影响,并且测试了复合粉体的遮盖力、吸油值、白度等性能及微观形貌。结果表明选取三乙醇胺为改性剂时,复合粉体的综合性能最佳,其中遮盖力为19．5g／m2,吸油值24．2g／100g,白度95．8％。     

Dispersion effect and auto-reconditioning performance of nanometer WS<Subscript>2</Subscript> particles in green lubricant

This paper reported on dispersion effect and dispersing techniques of nanometer WS₂ particles in the green lubricant concocted by us. And it also researched on auto-reconditioning performance of nanometer WS₂ particles to the abrasive surfaces of steel ball from four-ball tribology test and piston ring from engine lubrication test. The treated and untreated nanometer WS₂ particles were analysed by infrared spectrum. And the elementary component and interior elementary distribution of abrasive surface repaired by nanometer WS₂ particles were analysed by multifunction electron spectrometer. The results showed that the combinative method of ultrasonic dispersion, mechanical agitation and surface modification could improve the dispersion uniformity and stability of nanometer WS₂ particles in the green lubricant effectively. And the optimal ratio of the mass between surface modifier and nanometer WS₂ particles was 1: 2.5, the optimal treating time was 5 h. And IR analysis indicated that surface modifier could react with hydroxide radicals on surfaces of WS₂ particles and modify the surfaces, and the long lipophilic groups on surfaces of nanometer WS₂ particles could stretch in oil adequately and form steric hindrance layers between particles which prevented particles from conglomerating and depositing. In addition, tribological tests and surface analysis indicated that there were WS₂ adsorption film and reaction film on abrasive surfaces during the tribological tests, which could fill and level up the furrows on abrasive surfaces. As a result, the abrasive surfaces were repaired effectively by nanometer WS₂ particles.     

表面修饰二氧化硅微球的制备、表征及分散性能

采用一步法制备了亚微米纯二氧化硅微球及8种有机硅表面修饰的二氧化硅微球,用扫描电镜、氮吸附、零电荷点测定等方法对微球进行了表征,对比研究了微球在不同介质中的分散性能。所有微球都呈球形,形貌较好,依表面修饰基团的不同,粒子直径在0.42~0.54nm之间。所有微球均为实心,比表面积均小于21m2/g。微球的零电荷点在8.25~8.93之间变化。粒子经过表面修饰后,在不同介质中表现出了不同的分散行为,微球的分散行为可以由微球的亲水及疏水性,以及DLVO理论得到基本解释。