高岭石/苯甲酰胺插层复合物的制备与表征

以高岭石／二甲亚砜作为前驱物,用熔融插层法成功制备了高岭石／苯甲酰胺插层复合物,产物用X射线粉晶衍射和Fourier变换红外光谱进行了表征。实验结果表明：高岭石／苯甲酰胺插层复合物中,高岭石的层间距扩张到1.428nm,插层率达到了82．5％;苯甲酰胺分子的氨基与高岭石的内表面羟基形成了氢键,苯甲酰胺分子可能以单分子层垂直排列于高岭石层间。高岭石／苯甲酰胺插层复合物在140～180℃的温度范围内,会发生苯甲酰胺的脱嵌过程。     

高岭石/甘氨酸插层复合物的制备与表征

通过取代法成功地将甘氨酸插入到高岭石层间，制备出高岭石／甘氨酸插层复合物，XRD显示插层复合物1．0nm出现衍射峰，红外光谱表明甘氨酸分子中的N、O原子与高岭石片层间离子形成了氢键。     

超声波法制备高岭石插层复合物

用超声波法制备了高岭石插层复合物.利用红外光谱、X射线衍射和透射电子显微镜分析了不同产地高岭石结构的差异、插层效果以及它们之间的关系.比较了不同类型插层剂与高岭石的插层产物、插层效果及插层机理.结果表明:相同条件下,多水高岭石(埃洛石)和结构压力大的管状高岭石比普通高岭石更易于插层.在60℃,3 h,超声波条件下,将高岭石/二甲基亚砜(dimethylsulphoxide,DMSO)作为媒介,采用两步插层法快速制备高岭石/乙醇前驱体,但DMSO的插层率优于乙醇的.甲醇钠与苏州高岭石作用后,使部分苏州土片层间剥离.     

高岭石/酒石酸插层复合物的制备与表征

介绍了二甲亚砜(DMSO)取代法制备高岭石/酒石酸(标记为K/T)插层复合物.产物经XRD-6000粉晶衍射和傅立叶变换红外光谱表征.XRD表明:高岭石层间距由0.72 nm扩张到1.09 nm,插层率达50%.红外光谱表明:酒石酸分子的羰基与高岭石的内表面羟基形成了氢键,而羟基与高岭石的硅氧面的氧形成了氢键.酒石酸分子以单分子层平铺于高岭石层间.     

高岭石-氨基硅烷插层复合物的制备与表征

以高岭石-甲醇(K-M)复合物为前驱体,利用置换法于常温下制备了3种高岭石-氨基硅烷插层复合物。用X射线衍射、Fourier变换红外光谱仪、透射电子显微镜、热分析仪等对复合物进行了表征。结果表明:3种高岭石-氨基硅烷插层复合物的层间距均扩大至2nm以上,插层率都大于95%。3种氨基硅烷分子均和K-M前驱体的甲氧基共同存在于高岭石层间,均呈两层倾斜排列,倾斜程度不同。氨基硅烷的插入破坏了高岭石层间的氢键,加剧了高岭石自身结构中硅氧四面体片层与铝氧八面体片层之间的错位,使得复合物片层出现不同程度的卷曲变形。3种高岭石-氨基硅烷插层复合物的热分解过程均分三步进行:表面水的蒸发及层间甲氧基的脱嵌分解、插层剂氨基硅烷分子的脱嵌、高岭石脱羟基。     

淮北焦宝石型高岭石/二甲基亚砜插层复合物的制备与表征

采用XRF、XRD等研究了淮北高岭石的矿物学特征,结果表明淮北高岭石为隐晶质结构,结晶有序度低,Hinckley指数仅为0.56.以此为原料,制备了高岭石/二甲基亚砜插层复合物,并对其进行表征.XRD和FTIR分析显示DMSO插入了高岭石层间,使晶层间距d(001)由0.720 nm增加到1.132 nm,插层率为87％.DSC-TG分析显示插层复合物的脱嵌与挥发发生在120 ～280℃,高岭石的脱羟基温度在插层前后变化不明显.     

微波制备高岭石层间复合物的热解变化研究

研究了高岭石的反应活性及处理温度对高岭石层间复合物性能的影响。对样品进行了TG,DTG,DTA,FT-IR和XRD分析。结果表明,在较小粒度和较高浓度下,联氨和醋酸钾与高岭石的反应度分别为96%和89%;高岭石层间的醋酸钾在296 ℃之前稳定,296~440 ℃之间熔融,440 ℃之后分解;高岭石-醋酸钾层间复合物经500 ℃热处理后羟基谱带全部消失,比纯高岭石低150 ℃;高岭石-醋酸钾层间复合物在330 ℃以下结构是稳定的。     

高岭石/二甲亚砜插层复合物的热分析

用热重-差示扫描量热法(thermogravimetry-differential scanning calorimetry,TG-DSC)和X射线衍射研究了高岭石/二甲亚砜(dimethyl sulfoxide,DMSO)插层复合物形成时,吸附在高岭石表面的DMSO分子的存在状况.测量了复合物在60℃干燥不同时间和升温速率不同时的TG-DSC曲线.结果表明:复合物在60℃干燥24h后可将吸附分子除去,而不影响插入的DMSO;水和DMSO的脱附温度分别为60℃和117℃.根据热分析数据计算得到了Al2[SiO2O5](OH)4与DMSO的摩尔比值为1.04:1.研究发现:在高岭石的层间不存在水分子,水分子仅仅吸附在高岭石的表面.     

高岭石有机插层复合材料的研究及其应用

综述了高岭石/有机物插层复合物发展,分析了高岭石插层复合物插层机理,粘土矿物及高岭土有机物插层应用及插层复合物合成Sialon陶瓷的制备,并对其发展前景进行了展望.     

PAN/高岭石插层共混体系的制备与表征

用二甲基甲酰胺(DMF)对高岭石进行改性,改性的高岭石与聚丙烯腈(PAN)通过溶液插层制得共混复合物.用红外光谱和X射线衍射对复合物样品进行了结构分析与表征,结果显示:聚丙烯腈大分子插入到了高岭石片层之间,使高岭石层间距有一定程度的增大.对插层复合物的热稳定性和燃烧性能进行了研究,结果表明:共混复合物的的热分解温度提高,耐热性提高;同时,共混复合物的阻燃性能得到一定程度改善,极限氧指数从18.2%提高到了22.3%.     

高岭石有机插层反应的影响因素

利用高岭石的层状结构特征,将有机分子插入高岭石层间形成的高岭石有机复合物,兼具粘土矿物和有机物的特性,是一种新型矿物材料,在功能填料、陶瓷材料、催化剂、择吸附剂、环境修复材料等方面具有广泛的应用前景。高岭石层间氢键作用较强,有机分子的插层作用比较困难,合理控制插层条件是插层作用完成的关键。评述了高岭石特征、插层有机分子性质、水、温度、压力、PH值等因素对高岭石有机插层作用的影响。     

Electrorheological properties of kaolinite,polyindole, and polyindole/kaolinite composite suspensions

In this study, polyindole (PIN) and polyindole/kaolinite (PIN/KAO) composite were synthesized by free radical polymerization using FeCl₃ as an initiator. Average particle sizes (d₅₀) of PIN and PIN/KAO composite were determined by dynamic light scattering (DLS) as 7.2 and 6.2 μm, respectively. The samples were characterized by FTIR, elemental analysis, DSC/TGA and SEM measurements. Suspensions of KAO, PIN, and PIN/KAO composite were prepared in silicone oil (SO) and the sedimentation stabilities were determined. Electrorheological (ER) properties of these suspensions were studied as a function of dispersed phase concentration, shear rate, shear stress, and temperature; and yield stresses and excess shear stresses determined. Further, dielectric properties of KAO, PIN, and PIN/KAO composite were investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

二次插层法制备有机蒙脱石的研究

用甲基丙烯酰氧乙基三甲基氯化铵和十六烷基三甲基溴化铵作为插层剂,采取二次插层法制备了有机化蒙脱石,并对一次插层法和二次插层法的效果进行了比较,结果表明,经过二次插层反应后,蒙脱石的层间距从1nm左右增大至3nm,有利于有机分子的进入和形成新的蒙脱石有机复合物。     

凝聚共沉法改性高岭土/NR复合材料的性能研究

以浓缩NR胶乳为主体材料，改性高岭土为填料，用凝聚共沉法制备改性高岭土／NR复合材料，研究影响复合材料物理性能的因素，并对材料拉伸断裂面的形貌进行扫描电镜分析。结果表明，改性高岭土／NR复合材料具有优良的物理性能，且在拉伸过程中无应力发白现象；在改性剂乳酸钾溶液质量分数为0.05、高岭土改性温度为80℃以及改性高岭土用量为40份的条件下，制得的改性高岭土／NR复合材料物理性能最佳。     

Graphite intercalation compound with iodine as the major intercalate

Halogenated graphite CBr_xI_y (1 < y/x < 10) was made by exposing graphite materials to either pure Br₂ or an I₂/Br₂/HBr mixture to initiate the reaction, and then to iodine vapor containing a small amount of Br₂/HBr/IBr to complete the intercalation reaction. Wetting of the graphite materials by the I₂/Br₂/HBr mixture is needed to start the reaction, and a small amount of Br₂/HBr/IBr is needed to complete the charge transfer between iodine and carbon. The interplanar spacings for the graphite materials need to be in the 3.35 to 3.41 Å range. The X-ray diffraction data obtained from the halogenated HOPG indicate that the distance between the two carbon layers containing intercalate is 7.25 Å. Electrical resistivity of the fiber product is from 3 to 6.5 times the pristine value. The presence of a small amount of isoprene rubber in the reaction significantly increased the iodine-to-bromine ratio in the product. In this reaction, rubber is known to generate HBr and to slowly remove bromine from the vapor. The halogenation generally caused a 22% to 25% weight increase. The halogens were found uniformly distributed in the product interior. However, although the surface contains very little iodine, it has high concentrations of bromine and oxygen. It is believed that the high concentrations of bromine and oxygen in this surface cause the halogenated fiber to be more resistant to structural damage during subsequent fluorination to fabricate graphite fluoride fibers.     

Synthesis and intercalation of silver nanoparticles in kaolinite/DMSO complexes

Ag nanoparticles were synthesized in the interlamellar space of a layered kaolinite. Disaggregation of the lamellae of the nonswelling kaolinite was achieved by the intercalation of dimethyl sulfoxide (DMSO). The kaolinite was suspended in aqueous AgNO₃ solution and the adsorbed Ag⁺ ions were reduced on the surface of kaolinite lamellae with NaBH₄ or UV light irradiation. The silver nanoparticles formed were characterized by X-ray diffraction (XRD), small angle X-ray scattering (SAXS), and transmission electron microscopy (TEM). We studied the effects of the two reduction methods on the size and the size distribution of Ag nanoparticles and how clay mineral structure is altered as a consequence of particle formation. It was established that the size of Ag nanoparticles depends on both silver content and the reduction method. Photoreduction of silver led to the formation of relatively large Ag nanoparticles (diameter 8–14 nm).