苯甲酰胺分子在高岭石层间的成键和取向

利用X射线粉末衍射和Fourier变换红外光谱实验分析了2种高岭石及其苯甲酰胺插层复合物的结构.结构表征与分析表明:复合物的层间距分别扩张到1.437 nm和1.444 nm,苯甲酰胺分子在高岭石层间均呈单分子竖直排列,但与层间表面的倾斜状况不同.在佛山高岭石/苯甲酰胺插层复合物中,氨基和羰基同时参于与内表面羟基的作用;而在苏州高岭石/苯甲酰胺插层复合物中,只有氨基与内表面羟基成键,且苯甲酰胺分子还部分嵌入高岭石的复三方空穴.     

高岭石/聚苯乙烯插层复合物碳热还原反应制备碳化硅晶须/氧化铝复相陶瓷粉体

以二甲基亚砜(dimethylsuIfox.de,DMSO)为插层剂制得高岭石/DMSO插层复合物,将苯乙烯单体与高岭石,DMSO插层复合物进行置换反应, 成功地将苯乙烯单体引入高岭石层间,层间苯乙烯在加热条件下聚合,制得高岭石/聚苯已烯捅层复合物.以高岭石/聚苯乙烯插层复合物为原料,在氩气保护气氛下,于1500℃碳热还原反应制备碳化硅晶须/氧化铝(SiCw/Al2O3)复相陶瓷粉体.结果表明:在高岭石/聚苯乙烯插层复合物中,高岭石 的层间距由0.717nm扩张到1.130nm,插层率接近100%.插层作用影响了层间羟基基团的振动,使其键合方式发生改变.X射线衍射和扫描电镜分 析表明:合成出SiCw/Al2O3复相陶瓷粉体中SiC和Al2O3为主品相,SiC呈晶须状,其直径≤200nm,长度≥3μm.     

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。     

脂肪酸/高岭石插层复合物的制备及结构模型

以高岭土为原料、甲醇/高岭石插层复合物为前驱体,用脂肪酸插层处理,制备得到系列脂肪酸/高岭石插层复合物。利用X射线粉末衍射(XRD)、红外光谱(FTIR)及透射电子显微镜对结构与形貌进行了表征,讨论相同实验条件下,不同链长的脂肪酸插层高岭石后层间距及形貌的变化规律。结果表明:随着碳原子数增加,高岭石插层复合物层间距亦增大,层间距在2.36~4.13 nm之间。高岭石复合物层间距与脂肪酸碳原子数变化呈正相关关系,表明不同碳原子数的脂肪酸在高岭石层间的排列方式相似。当碳原子数≥14时,高岭石片层的边缘开始出现卷曲,且随着碳原子数的增加,卷曲片层数目增多,卷曲程度增大。综合分析XRD和FTIR结果,结合脂肪酸分子空间尺寸,提出脂肪酸分子在高岭石层间的排列模型。     

高岭土/咪唑插层复合物的制备与表征

以高岭石/二甲基亚砜插层复合物作为前驱体,采用二次取代法制备了高岭石/咪唑插层复合物,采用X-射线衍射、红外光谱、激光粒度分析等技术对产物进行表征。实验结果表明:咪唑已成功插入到高岭石中。XRD分析表明:在高岭石/咪唑插层复合物中,高岭石的层间距由0.72nm扩张到1.125nm,插层率达到了71.7%,红外光谱研究表明,插层中咪唑分子中的N-H基与高岭石内表面羟基之间产生了N-H-OH作用,形成了新的氢键;热重-差热曲线(TG-DTA)分析表明:高岭石/咪唑插层复合物在130～220℃的温度范围内,会发生咪唑的脱嵌过程,粒度分析表明:高岭石粒径小于5μm的颗粒占总颗粒数的比例降低了12.66%。     

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/苯甲酰胺插层复合物的制备和表征

在60℃下,高岭石与二甲基亚砜反应制备高岭石/二甲基亚砜插层复合物,使用X衍射分析、热分析、红外光谱分析对其进行表征。在140℃下,苯甲酰胺与高岭石/二甲基亚砜插层复合物反应4 d,得到高岭石/苯甲酰胺插层复合物,对其进行表征,然后与高岭石/二甲基亚砜插层复合物进行对比。结果表明：在没有二甲基亚砜作为前驱体的情况下,苯甲酰胺不能与高岭石直接进行反应;高岭石/苯甲酰胺插层复合物结构的稳定性好,是由于苯甲酰胺插层内羰基中的氧原子与高岭石层间表面上的铝硅酸盐形成氢键。     

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。     

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.     

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.     

高岭石/丙烯酰胺插层复合物的微波制备及其表征

高岭石及其有机插层复合物在高性能陶瓷领域有着良好的应用前景。本文利用微波技术,以DMSO作为前驱体,制备高岭石/丙烯酰胺插层复合物,发现微波对丙稀酰胺的插层反应具有相当明显的促进作用,反应时间从通常的几天缩短到几个小时。采用X-射线衍射、FT-IR光谱、TG等技术对其进行表征。结果表明:反应2小时后,该插层复合物的层间距即可扩大为1.139nm,其键合方式发生了改变,形成新的氢键。这为工业生产高岭石有机插层物以及制造纳米级高岭土提供了高效的新途径,并为进一步生产高性能陶瓷方面打下了基础。     

An insight on the weakening of the interlayer bonds in a Cameroonian kaolinite through DMSO intercalation

In this study, intercalation of dimethylsulphoxide (DMSO) in a Cameroonian kaolinite is used to achieve weakening of the interlayer hydrogen bonds, in the perspective of dispersion or even exfoliation of the clay within polymer composite materials. Displacement of intercalated DMSO by ethyl acetate and ammonium acetate is studied in order to simulate the interactions with the polymer matrix. The exfoliation of the kaolinite is well evidenced by X-ray diffraction and SEM observations. The disruption of the interlayer bonds is shown by the displacement of the FT-IR vibration modes of both Al–OH and Si–O functions, and by the decrease of the dehydroxylation temperature recorded by Controlled Rate Thermal Analysis. Complete displacement of DMSO by ethyl acetate is achieved and the crystalline structure is deeply disordered as a result of interlayer bonds weakening. The displacement of DMSO by ammonium acetate leads to a ternary composite of DMSO/ammonium acetate with respective intercalation ratio of 62.4% and 57.7%.     

Kaolinite nanomaterial: Intercalation of 1-butyl-3-methylimidazolium bromine in a methanol–kaolinite pre-intercalate

Intercalate nanomaterial comprising of ionic liquid 1-butyl-3-methylimidazolium bromine [bmim]Br and methanol-pretreated kaolinite was prepared. We study several physical properties of the new intercalation compound by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Thermogravimetric analysis and differential scanning calorimetry (TG–DSC), UV–vis spectra and scanning electron microscopy (SEM). The intercalation compound shows an increase of the basal spacing from 0.72 nm (for kaolinite) to 1.42 nm (for the material with the guest). Intercalated compound shows an increase in the thermal stability. Finally, the UV–vis spectra reveal significant absorption in the UV region for this inclusion compound.     

Characterization of kaolinite intercalation compounds with benzylalkylammonium chlorides using XRD,TGA/DTA and CHNS elemental analysis

Kaolinite of high structural order was intercalated with selected ammonium salts containing a benzyl group: benzyltrimethylammonium (B1), benzyltributylammonium (B2), benzalkonium (B3), benzyldimethyltetradecylammonium (B4) and benzyldimethylhexadecylammonium (B5) chlorides. As a precursor, a methoxy-kaolinite was used which had OCH₃ methoxyl groups attached to the octahedral sheet. Such change of the octahedral surface character enabled intercalation of the salts which was not possible using other precursors (e.g. kaolinite–dimethyl sulfoxide). The new intercalation compounds were characterized using XRD (X-ray diffraction), thermal analysis (TGA/DTA) and CHNS elemental analysis. The XRD revealed a significant shift of the kaolinite basal reflection to higher values range from ~ 14 Å (B1 salt) to ~ 38 Å (B5 salt) which confirmed the intercalation. The d values depended on the type of used salt as well as on its initial concentration. The estimated space occupied by each molecule enabled to calculate the maximal molar capacity of the kaolinite in relation to the salts. The results were compared with the chemical formulas of the materials calculated on the basis of CHNS measurements. The TGA/DTA analyses were helpful to confirm the successful intercalation of the selected salts as the thermal decomposition of the kaolinite derivatives took place at higher temperatures as compared to appropriate physical mixtures.     

Mechanochemical intercalation of low reactivity kaolinite

Complete urea-intercalation of a low reactivity kaolinite from Birdwood has been carried out by co-grinding with urea in the absence of water (mechanochemical intercalation). The effectiveness of mechanochemical intercalation was compared to solution intercalation by X-ray diffraction (XRD), thermal analysis (TG, DTG), diffuse reflectance Fourier transform infrared (DRIFT) spectroscopy and scanning electron microscopy (SEM). In aqueous solution of urea the Birdwood kaolinite was intercalated with difficulty and only 12% intercalation was achieved. After 2 h of co-grinding with solid urea, complete (100%) intercalation was attained. The possible explanation of complete intercalation is that co-grinding of Birdwood kaolin with solid urea can remove the high-defect kaolinite coating, which prevents the intercalation of the low-defect kaolinite particles. The mechanochemical treatment increased the degree of intercalation and in parallel reduced the amount of the crystalline kaolinite phase.     

高岭石／二甲基亚砜插层复合物的制备及影响因素

以高岭土为原料,制备了高岭土／二甲基亚砜（dimethylsulfoxide,DMSO）插层复合物。利用X射线衍射（x-raydiffraction,xgo）,Fourier红外光谱（Fouriertransforminfraredspectracopy,FTIR）,热重一差热分析（thermogravimetric-...     

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。