微结构特征对高岭石插层反应的影响Ⅰ--特征基团红外吸收光谱研究

Effect of Microstructure on the Intercalation of Kaolinite Ⅰ——IR Spectra Study of Characteristic Bands

HI指数一直被用以判别高岭石的结构有序度,并被看作是影响高岭石插层反应程度的重要因素。本文以HI指数分别为1.25、0.71、0.52和0.18的高岭石为原料,用功能基团的红外光谱特征作为高岭石微结构的重要标志,总结层间微结构与结晶度指数的关系。在此基础上用极性有机小分子NMF对高岭石进行插层修饰,研究微结构特征对高岭石插层反应的影响。研究结果表明:红外吸收峰3696cm-1相对强度大小顺序与HI指数的顺序一致,而OH振动峰和Si-O振动峰的相对强度也存在一定的规律性。Si-O弯曲振动区吸收峰540cm-1、471cm-1、432cm-1强度差最大的龙岩高岭石(HI=0.52)最容易进行插层,其插层率可以达到99.8%,而强度差最小的大同高岭石(HI=0.71)反应最难进行。因此得出结论:仅以结晶度指数来判断插层反应进行的程度存在一定的局限性,而结合功能基团红外光谱的相对强度能更准确的对插层反应进行表征。

Crystallinity index is used to estimate the order of the kaolinite and it is the important factor of the intercalation,but there were some exception in service. The relative intensity of the functional groups （Si-O, O-H） of the kaolinite with different crystallinity index （HI=1.25, 0.71, 0.52 and 0.18） were analysed by the IR spectra of the functional groups to include the relation between the microstructure of the interlayer and the crystallinity index. In the presented experiments,the kaolinite＋N-methylformamide intercalates were investigated to research the relation btween the microstructure and the intercalation. The results indicated that the relative intensity of 3696cm^-1 was consistent with the order of the HI. And the bands of OH and Si-O groups had definite rules. Longyan kaolinite with the maximal difference of Si-O（540cm^-1,471cm^-1 and 432cm^-1） bands had the biggest intercalation rate which was up to 99.8%. Datong kaolinite with the minimal difference of Si-O had the opposite characteristic to the Longyan kaolinite. It indicated that it is limited to imply the degree of intercalated action only depending on the HI index,however, it was exact to imply it to combine the crystallinity index and the relative intensity of the functional groups.