高岭石纳米插层复合物的制备和热分析研究

发布时间：2018-11-11 11:14

【摘要】：高岭石纳米插层复合材料的研究成为材料科学中一个极富生命力的领域。一些极性小分子可以通过插层反应进入高岭石层间并与其形成氢键,具有特定的空间取向,可实现分子的定向排列和自组装。因此研究高岭土插层反应机理及复合物的微观结构在材料学和矿物学及物理、化学领域具有极大的实际意义和研究空间。但由于高岭石特殊的层间结构使其插层困难,目前国内外的研究基本上还只是停留在制备和结构表征阶段,缺乏对于插层机理及机制的系统研究,对同种高岭石采用多种插层剂制备得到的复合物进行分析,便于系统的探讨复合的热分解过程,对插层机理进一步补充和完善。本文以液相悬浮法直接插层得到高岭石/甲酰胺和高岭石/二甲基亚砜插层复合物,以机械力化学插层法和液相悬浮法制备得到高岭石/乙酰胺插层复合物,以液相悬浮法和二次插层制备得到高岭石/苯甲酰胺和高岭石/甲醇插层复合物。采用X射线衍射(XRD)、傅立叶变换红外光谱(FTIR)、热分析(TG-DSC)等技术对复合物进行结构及性能的表征,探讨复合物的热分解过程,研究复合物的两个分解阶段与插层剂的分子量和沸点等的联系,并对五种复合物的热分析数据进行对比,从而寻找插层剂属性对复合物的影响规律。结果表明,插层的有机小分子与高岭石内表面形成氢键,高岭石层间距扩大,不同的插层剂形成的氢键结合方式以及层间距不同。有机酰胺插层剂分子与高岭石层间的键合作用相同,胺基的H原子与高岭石内表面羟基上的O原子形成氢键;二甲基亚砜S=O键的氧原子与铝氧八面体的氢原子形成氢键;甲醇中羟基的H原子与铝氧八面体的氧原子形成氢键。插层剂脱嵌阶段,不同基团插层剂分子脱嵌温度从大到小排列为:羟基成键氨基成键S=O成键。相同基团的插层剂分子,分子量越大,脱嵌温度越高,即苯甲酰胺乙酰胺甲酰胺。脱羟基阶段,插层剂分子量越大,复合物脱羟基温度越低,苯甲酰胺插层复合物脱羟基温度最低,甲醇最高,但低于纯高岭石的脱羟基温度。插层剂的脱嵌包含2个过程,氢键的打破和插层剂的扩散。脱嵌反应吸收热与插层剂分子量大小成正比,苯甲酰胺分子量最大,反应吸收热最多,甲醇分子量最小,反应吸收热最少。
[Abstract]:The research of kaolinite nanointercalation composites has become a vital field in material science. Some polar small molecules can intercalate into kaolinite layers and form hydrogen bonds through intercalation reaction. They have special spatial orientation and can realize the orientation and self-assembly of molecules. Therefore, the study of the mechanism of kaolin intercalation reaction and the microstructure of the composite has great practical significance and research space in the fields of materials, mineralogy, physics and chemistry. However, because of the special interlayer structure of kaolinite, the intercalation of kaolinite is difficult. At present, the research at home and abroad is still mainly at the stage of preparation and structure characterization, and there is no systematic study on intercalation mechanism and mechanism. The composite prepared from the same kaolinite with various intercalators is analyzed, which is convenient to discuss the thermal decomposition process of the composite, and to further supplement and perfect the intercalation mechanism. In this paper, kaolinite / formamide and kaolinite / dimethyl sulfoxide intercalation complexes were prepared by liquid suspension method, and kaolinite / acetamide intercalation complexes were prepared by mechanochemical intercalation and liquid suspension. Kaolinite / benzoamide and kaolinite / methanol intercalation composites were prepared by liquid suspension and secondary intercalation. The structure and properties of the composites were characterized by X-ray diffraction (XRD), (XRD), Fourier transform infrared spectroscopy (TG-DSC) and (FTIR), thermal analysis (TG-DSC), and the thermal decomposition process of the composites was discussed. The relationship between the two decomposition stages of the complex and the molecular weight and boiling point of the intercalant was studied, and the thermal analysis data of the five complexes were compared to find out the influence of the properties of the intercalation agent on the complex. The results show that the intercalated organic small molecules form hydrogen bonds with the inner surface of kaolinite, and the interlayer spacing between kaolinite and kaolinite is enlarged, and the hydrogen bonding modes and interlayer spacing of different intercalators are different. The bond between organic amide intercalator molecule and kaolinite layer is the same. The H atom of amino group forms hydrogen bond with O atom on the inner surface of kaolinite, and the oxygen atom of dimethyl sulfoxide is formed hydrogen bond with hydrogen atom of aluminum oxide octahedron. The H atom of the hydroxyl group in methanol forms a hydrogen bond with the oxygen atom of the aluminium octahedron. In the deintercalation stage of the intercalator, the molecular desorption temperature of different group intercalators ranged from large to small as follows: hydroxyl bonding, amino bonding, Schio bonding. The higher the molecular weight and the higher the desorption temperature of the intercalator molecule of the same group, namely benzamide acetamide formamide. In the dehydroxylation stage, the higher the molecular weight of the intercalant, the lower the dehydroxyl temperature of the complex, the lowest and the highest methanol, but lower than the pure kaolinite. The deintercalation of intercalator consists of two processes, hydrogen bond breaking and intercalant diffusion. The absorption heat of deintercalation reaction is proportional to the molecular weight of the intercalant, the molecular weight of benzoamide is the largest, the absorption heat of reaction is the most, the molecular weight of methanol is the least, and the heat of reaction absorption is the least.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332

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