改性高岭土对NR性能的影响

本实验采用干法改性工艺,选用硼酸酯类改性剂对广西北海高岭土进行改性。对改性高岭土进行活化指数测定,以确定最佳改性剂用量和最佳改性时间。最后选取改性效果最好的高岭土取代部分白炭黑,制备天然橡胶复合材料。主要考察填料配合对橡胶复合材料力学性能的影响。实验结果表明,对北海高岭土进行表面有机改性,改性剂加八量为20％,改性时间为20min,改性高岭土的活化指数最高,改性效果最佳。用改性高岭土取代白炭黑后,胶料的加工性能改善,硫化胶的物理性能变化不是很大,但可以降低生热、滚动阻力和能耗。     

Synergistic effect of talc/calcined kaolin binary fillers on rigid PVC: Improved properties of PVC composites

This study aims to develop poly(vinyl chloride) (PVC) composites prepared by melt mixing by using a combination of talc and calcined kaolin as filler in order to improve the disadvantages of rigid PVC, which is widely used in industry, such as poor mechanical properties and low thermal stability. In addition, PVC/talc and PVC/calcined kaolin composites were also examined for comparison. The calcined kaolin is modified with urea to increase the surface area (chemical treatment), while the surface of both fillers is coated with stearic acid for good compatibility with PVC (mechanical treatment). Scanning electron microscopy micrographs showed homogeneous distribution of mechanically processed fillers. Attenuated total reflectance–Fourier-transform infrared spectroscopy analysis revealed successful coating of the fillers with stearic acid. Also, new bands were detected in the spectrum of urea-treated calcined kaolin, showing an effective chemical treatment. It has been observed that the treatment of fillers improves the mechanical properties of PVC. Thermogravimetric results showed that delaminated calcined kaolin increased the thermal stability of PVC composites. The results of this study proved that binary filler composites combine good properties of both (synergistic effect) and good filler dispersion can be obtained by using stearic acid and urea.     

硫酸改性高岭土的制备及表征

为了对比高岭土改性前后的结构变化,将鄂尔多斯高岭土分别用10%、20%、30%、40%、50%的硫酸进行改性,得到酸改性高岭土样品。采用IR、XRD、SEM、BET、EDS等对样品进行表征分析。结果表明,由于硫酸的吸水性,随着酸浓度的增加,脱除高岭土中吸附水的能力越强;酸改性浓度的变化对高岭土的结构影响不大;改性后的高岭土比表面积减小,表面粗糙度增加,密集堆积,凝结成块状,有堆积孔道出现;硫酸改性会使高岭土中大量的铝被浸出。     

Novel‐modified kaolin for enhancing the mechanical and thermal properties of poly(vinyl chloride)

Novel surface‐modified kaolin with liquid‐like behavior was prepared. The characteristics of the solvent‐free kaolin fluid were evaluated by using Fourier transform infrared spectroscopy, WAXD, thermogravimetric analysis, and transmission electron microscopy. The polyvinyl chloride (PVC)/solvent‐free kaolin fluid composites were also fabricated via melt mixing. Owing to the novel surface modification, the hydrophilic kaolin surface grafted long organic chains, which made that the solvent‐free kaolin fluid could be well dispersed in PVC matrix and firmly integrated with the PVC matrix. The resulted composites exhibited better heat resistance and mechanical properties than neat PVC resins. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

季铵盐表面活性剂改性对高岭土纳米管吸附脱硫性能的影响

以煤系高岭土为原料,通过插层反应,成功制备了高岭土纳米管,管的内径为8~25 nm,长度为0.1~0.5 μm,长径大,均一性好。选用3种季铵盐表面活性剂：十六烷基三甲基氯化铵（CTAC）、十六烷基三甲基溴化铵（CTAB）和十二烷基三甲基溴化铵（DTAB）对高岭土纳米管进行改性,考察了不同种类、不同浓度的表面活性剂分子对高岭土纳米管结构和吸附脱硫性能的影响。结果表明,经过表面活性剂改性后高岭土纳米管的吸附脱硫能力有所增强,尤其以0.5 mol/L CTAC甲醇溶液改性后,高岭土纳米管的脱硫率有明显增加,从原来40.5%增加到60.3%。     

湛江高岭土作FCC催化剂载体可行性试验研究

对湛江高岭土的物化性质进行分析测试,并对以湛江高岭土为载体制备的半合成催化剂进行评价。结果表明,湛江高岭土晶体结构以片状为主,粒度分布较为集中,化学组成与苏州高岭土基本相当;采用湛江高岭土为载体的催化剂,其质量指标和裂化性能与对比样相当,可以满足FCC催化剂质量指标的要求。     

Technical Relevance of Epoxy/Clay Nanocomposite with Organically Modified Montmorillonite: A Review

This review covers almost all known categories of compounds used for nanoclay surface modification with special emphasis on organic modification of layered silicate montmorillonite. Commonly used organic modifiers include quaternary ammonium ions, quaternary phosphonium ions, and amino acids. Dispersion of organomodified nanoclays in epoxy is particularly focused upon in this article. Epoxy-based materials are used as convenient matrices for montmorillonite dispersion since years due to superior properties of resulting polymeric nanocomposites, such as mechanical strength, electrical conductivity, flammability, and thermal stability. Owing to their high performance epoxy nanocomposites have endless applications in aerospace, automotives, construction, electrical, adhesives, and coating industries.     

Surface Protection of Quaternary Gold Alloys by Thiol Self-Assembled Monolayers

This work deals with a physical and chemical surface characterization of quaternary 18K, 14K, and 9K gold alloys and pure polycrystalline gold substrates. Surface microstructure and composition are evaluated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray fluorescence spectroscopy. Corrosion resistance of 18K gold alloys is explored by potentiodynamic polarization showing the influence of the manufacturing process on materials fabricated as plates and wires. The research is also in the framework of one of the most common strategies on the modification of metallic surface properties, i.e., the building of self-assembled monolayers (SAM) from organic thiols. The metal affinity of the head group to produce the coating of the substrate by covalent binding is approached by using thiol compounds with different molecular structures and functional group chemistries exposed to an electrolyte solution. Therefore, a comparative study on the surface protection of a quaternary 18K gold alloy and pure gold substrates by SAMs of 6-mercaptopurine (6MP), 1-decanethiol (DT), and 11-mercaptoundecanoic acid (MUA) has been carried out. Surface modification and SAM organization are followed by cyclic voltammetry (CV), and the behavior of the double layer of the electrode–electrolyte interface is evaluated by electrochemical impedance spectroscopy (EIS). The study of these materials allows us to extract fundamental knowledge for its potential application in improving the bioactive properties of different jewelry pieces based on 18K gold alloys.     

MAS NMR study of surface-modified calcined kaolin

Calcined kaolins, modified by a silane coupling agent, were analyzed by magic angle spinning nuclear magnetic resonance (MAS NMR) and compared to unmodified samples. The results show no chemical shift for ²⁹Si, whereas there is a marked change for ²⁷Al. The chemical shifts of 5.44 and 65.69 ppm of ²⁷Al in unmodified samples are respectively moved to 3.8–4.4 and 54.6–59.9 ppm after modification. This is attributed to changes in the chemical environment around the surface Al ions on the calcined kaolin resulting from chemical bonding of the silane coupling agent molecules to the Al. The results demonstrate that MAS NMR is a useful technique for characterizing the surface modification mechanisms of minerals.     

两种改性高岭土减排超细颗粒物的对比分析

选用盐酸加锰酸钾改性和氢氧化钠改性两种典型的改性方法,期望利用盐酸和锰酸钾的强酸性和强氧化性、氢氧化钠的强碱性改变高岭土的物理化学特性,提高其捕获超细颗粒物的效率。选用典型煤种,将改性前、后的高岭土吸附剂混煤并送入高温沉降炉中燃烧,获得颗粒物的质量粒径分布。结果表明,酸改性能明显提高高岭土捕获PM_0.2(空气动力学直径小于0.2 μm)的效率,但碱改性效果相反。根据表征分析,酸改性明显削弱了Al-OH、Al-O-Si、Si-O和Si-O-Si四个官能团,促进了高岭土捕获碱金属的反应,提高了捕获PM_0.2的效率;而碱改性虽然削弱了Si-O和Si-O-Si两个官能团,但增强了Al-OH和Al-O-Si两个官能团,增强的官能团抑制了高岭土捕获碱金属的部分反应,导致高岭土捕获PM_0.2的效率降低。     

Surface modification with cold plasma application on kaolin and its effects on the adsorption of methylene blue

In this study, cold plasma treatment was applied for the surface modification of kaolin adsorbent to improve the removal of methylene blue (MB) from aqueous solution. To achieve the aim, the conditions for adsorption, including cold plasma application time, initial dye concentration, and pH were investigated with respect to the removal efficiency of MB. The changes of the surface property before and after cold plasma treatment were discussed. The maximum adsorption capacity of MB compared with untreated raw kaolin increased from 19.60 to 51.02 mg/g (up to approximately 2, 5-fold) after modification by cold plasma. The experimental data were analyzed using pseudo first-order and second-order kinetic models. The surface properties of kaolin treated with cold plasma were investigated with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and point of zero charge (pzc) measurements to understand the adsorption mechanism.     

煤系高岭土表面改性及在高分子材料中的应用

介绍了煤系高岭土的特征、对其表面改性的目的及改性设备和工艺,浅析了硅烷偶联剂和钛酸酯偶联剂的构造与改性机理,综述了我国煤系高岭土在高分子材料中的应用情况。     

茂名高岭土制备裂化催化剂的特性

测定分析了茂名高岭土晶相和化学组成,以球磨茂名高岭土为原料,采用原位晶化法制备了FCC催化剂,研究了所制备催化剂的特性.结果表明茂名高岭上的Na<,2>O含量较高,但K<<2>O含量较低,碱金属总量(Na<,2>O+K<,2>O)与普通商用对比高岭土相当;晶相高岭石含量为85%,并伴有极少量的叶蜡石;球磨茂名高岭土制备...     

Decolorization of Rice Bran Oil Using Modified Kaolin

Measurements show that kaolin from Ranong, obtained from a major deposit in southern Thailand, can be modified to produce a material that is suitable for decolorizing rice bran oil. Its sorption properties were determined after various physical and chemical modifications of this kaolin. Physical modification was achieved by grinding via a planetary ball mill (300 rpm for 1 h), and this was followed by chemical treatment using sulfuric or oxalic acids. The optimum decolorization capacity (~80%) was achieved by using 2 M sulfuric acid. With oxalic acid, the best results were obtained with 0.7 M, but these were slightly lower than those obtained with 2 M sulfuric acid. Compared to the original kaolin sample, the specific surface area of the modified clay increased from ~13 to ~244 cm² g⁻¹, and the total pore volume from 0.06 to 0.43 cm³ g⁻¹. The pore size distribution curves show that most pores are in the mesoporous region with their diameters between 3.0–4.5 nm, and are suitable for adsorption of pigment molecules that are present in rice bran oil. Desorption and spectroscopic studies suggest that both electrostatic and chemical processes are involved in the interaction between pigments and active sites on the clay surface.     

焙烧高岭土的结构特征和吸附性能

通过对焙烧高岭土的矿物特性和表面吸附性质的研究。用化学分析，ＸＲＤ、ＩＲ、ＸＰＳ、Ｒａｍａｎ光谱和ＳＥＭ观察证明焙烧高岭土的羟基基团完全消失，等温吸附，粒度分布试验证明焙烧高岭土水化能力较大，但吸附能力较弱。     

高岭土的球磨疏水改性及其在海藻酸盐凝胶微球中的应用

为了提高高岭土(KL)对疏水性有机农药的亲和力,以聚甲基氢硅氧烷(PMHS)作为疏水改性剂,采用球磨法改性KL。进而,采用负压冷冻干燥技术将甲氨基阿维菌素苯甲酸盐(EB)负载到改性高岭土颗粒上,然后包覆于海藻酸盐基质中制得载药改性高岭土/海藻酸钙复合凝胶微球(MKL-CA-CMBs)。通过Zeta电位及激光粒度仪、FTIR、SEM、XRD、比表面积及孔径分析仪对改性后KL的结构、形貌和性能进行了表征,同时对MKL-CACMBs的载药和释药性能也进行了考察。结果表明,在球磨机械力作用下,PMHS以物理吸附或化学吸附的方式吸附于KL颗粒表面。改性后的KL粒径减小、比表面积增大,疏水性增强,利于疏水有机农药的负载,使高岭土/海藻酸钙复合凝胶微球(KL-CA-CMBs)的载药率(DLR)和包封率(EE)分别由6.5%和53.1%增长至9.7%和72.5%。MKL-CA-CMBs所具有的缓释性能主要基于MKL对疏水有机农药的亲和能力,剂型的释放模型属于Non-fickian扩散模型。     

钼磷改性高岭土的制备及表征

为了提高废水处理的效果,以高岭土为载体,制备了负载型的钼磷改性高岭土催化剂,并采用红外光谱(FTIR)、X射线衍射分析(XRD)、扫描电镜(SEM)和差示扫描量热(TG-DSC)手段对制备的改性高岭土进行了表征,结果表明:高岭土经改性后,高岭土中的Al-O八面体结构部分被破坏,从而使Al-O-Si的伸缩振动发生畸变形成...     

酸和碱处理对内蒙古煤系高岭土结构和裂化性能的影响

利用NaOH溶液和HCl溶液分别对内蒙古煤系硬质高岭土进行酸和碱处理。采用固体核磁共振、BET、TPD以及裂化活性测试（在小型固定床上以酸处理高岭土对大港轻柴油进行催化裂化）等分析方法对比研究了煤系高岭土酸和碱处理后物化性能和裂化性能变化。结果表明，酸和碱处理都可以使高岭土获得（2～8） nm的孔径分布，并获得较好的催化裂化性能；Al(Ⅳ)有利于裂化反应，可以通过酸和碱反应改变高岭土中Al(Ⅳ)的比例来调节其裂化性能；酸处理后的高岭土酸性位数量明显高于碱处理土；碱处理高岭土的裂化性能优于酸处理高岭土。     

改性煅烧剥片高岭土对PVC塑料的改性作用

采用PVC树脂为主原料,以4种改性高岭土为改性剂和其他助剂相混合填充PVC塑料制成改性塑料,研究了4种改性高岭土对改性塑料的力学性能和电学性能影响。改性煅烧剥片高岭土的性能最优,其最佳添加量为10～20份。     

High performance alkyd paints based on platy kaolin for corrosion protection of steel

Calcination of kaolin presents an easy route to obtain high performance and eco-friendly anticorrosive filler. The objective of the present work was to prepare a new ecologically friendly inorganic filler, based on thermal treatment of kaolin to be used as an anticorrosive. This work studied the corrosion protection of medium oil-modified alkyd paints based on thermally treated kaolin at different temperatures. Paints were formulated with different pigment volume concentrations (PVCs) and critical pigment volume concentrations (CPVCs). The prepared paints were formulated with increasing content of kaolin, with PVC ranging from 10 to 30%. The physical and chemical properties of kaolin were evaluated at different temperatures. Particle shapes of thermally treated kaolin were characterized using scanning electron microscopy. The physico-mechanical properties of dry films, water vapor transmission and their corrosion properties using accelerated laboratory corrosion test were tested. The thermal treatment of kaolin enhanced both the oil absorption and the alkalinity. This led to alkyd results in saponification and consequently passivation of the substrate. Good wetting with alkyd resin gave homogeneous films without defects which resisted water and oxygen permeation and protected steel against corrosion. The results revealed that thermally treated kaolin at 400°C was the best at protecting steel substrates for all PVCs.