摘要
采用γ-氨丙基三乙氧基硅烷(APTES),在乙醇-水混和溶剂中对预先经不同温度煅烧的蒙脱石进行改性。采用XRD、FTIR、热分析、元素分析、比表面积及孔分析等多种手段对产物进行分析。结果表明:硅烷主要赋存于蒙脱石层间,呈双层排布,少量嫁接于片层端面。热处理温度通过影响蒙脱石层间含水量,进而影响硅烷在层间的水解缩合。硅烷改性蒙脱石的过程为:硅烷分子通过阳离子交换插层至蒙脱石层间;随后水解生成的硅醇分子相互缩合;最终由于乙醇对硅烷水解的抑制作用以及蒙脱石片层相邻电荷位点存在一定的间距,与蒙脱石片层结合较弱的硅烷分子被洗脱,剩余的Si-O-Si交联网络在层间形成类似"柱子"结构。该硅烷改性蒙脱石与原始蒙脱石的比表面积相差不大,但其结构中微孔的比重增加。
The interaction between γ-aminopropyltriethoxysilane and montmorillonites with different heat-treated temperatures in ethanol-water system was investigated. Samples were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis and nitrogen adsorption-desorption i- sotherms. Result suggested that most of the silane molecules existed in the interlayer of montmorillonite and a few of them were grafted on the edge of the layers. The loading amount of silane was respected with the water contents in the interlayer spaces of montmorillonite. Heat treatment reduced the interlayer water contents and consequently affected the grafting reaction. The process of grafting started with the ion exchange of silane molecules With the cation in the interlayer spaces of montmorillonite, and these molecules were adopted bilayer arrangements. Then the hydrolyzed silane molecules were condensated with each other. Owing to the inhibition of ethanol to the hydrolysis of silane and the distance between the adjacent charge sites of the layers, the residual Si-O-Si cross-linked network constituted a ＂pillar＂ structure. These modified products were hydrophobic and had the similar specific surface areas of montmorillonites.
出处
《矿物学报》
CAS
CSCD
北大核心
2012年第1期14-21,共8页
Acta Mineralogica Sinica
基金
国家自然科学基金(批准号:U0933003)
国家杰出青年基金(批准号:40725006)
关键词
蒙脱石
热处理
硅烷
改性
孔结构
montmorillonite
heat treatment
silane
modification
pore structure
