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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 montmorillonite, previously calcined at different temperatures, was modified with γ-aminopropyltriethoxysilane (APTES) in an ethanol-water mixed solvent. The products were analyzed by XRD, FTIR, thermal analysis, elemental analysis, specific surface area and pore analysis. The results show that silane mainly exists in the interlayer of montmorillonite with a bilayer arrangement and a small amount of graft on the end face of the sheet. The temperature of the heat treatment affects the hydrolysis and condensation of silane in the interlayer by affecting the water content of the interlayer of the montmorillonite. Silane modified montmorillonite process: silane molecules through cation exchange intercalation to the montmorillonite layer; followed by hydrolysis of silanol molecules condensed with each other; eventually due to ethanol inhibition of silane hydrolysis and montmorillonite lamellar phase The adjacent charge sites are spaced apart, and the silane molecules that are weakly bonded to the smectite sheet are eluted. The remaining Si-O-Si crosslinked network forms a “pillar-like” structure between the layers. The silane-modified montmorillonite and the original montmorillonite specific surface area is not much difference, but the structure of the micropore proportion increased.