醋酸钾/偏高岭石插层复合材料的制备及机理研究

摘要

Potassium acetate/metakaolinite intercalated composites were successfully prepared by mechanical grinding at the room temperature. The structure of metakaolinite before and after the intercalation was studied by XRD, FTIR and TEM. It was found that potassium acetate was first coordinated with water molecules and then moved into the interlayer of metakaolinite by mechanical grinding, resulting in the expansion of metakaolinite layers. During the heat treatment, water volatilization also led to the expansion of metakaolinite layers. In intercalated composites, acetate ions were coordinated with the gibbsite-type layers through water molecules bridging. Besides, the hydrated K~+ cation stayed near the silica-type layers with the negative charge so as to keep charge balance.%采用机械研磨法,成功制备了醋酸钾/偏高岭石插层复合材料.通过XRD、FTIR和TEM研究了插层前后偏高岭石结构的变化,提出了该复合材料的插层机理和结构模型:首先醋酸钾与水分子以配位键结合,然后通过机械研磨作用进入偏高岭石层间,并将偏高岭石片层撑开.当进行热处理时,水的挥发也会对偏高岭石片层起到撑开作用.最终导致偏高岭石被撑开、剥离.在插层复合材料中,醋酸根与偏高岭石的铝氧层通过水分子桥接方式连接,钾离子水合物为保持电中性,位于带负电的硅氧层附近.