Abstract: Montmorillonite was modified with mono-functional γ-aminopropyl dimethyl ethoxymsilane. Presence of chemical bond between montmorillonite and coupling agent was testified by infrared spectroscopy (IR) characterization. A yellow salicylaldimine Schiff’s base which absorbed visible light at 404nm was formed by reaction of salicylaldehyde with amino silane，therefore this specific chromogenic reaction could be used to evaluate reaction ratio of the silane coupling agent. Quantity of active silanols on montmorillonite was 29.6 mmol/(100g MMT)，and the best drying temperature of silylation reaction was 120 ℃ through the above method. X-ray wide angle diffraction (XRD) test showed that active silanols were distributed on the broken edge rather than on the interlayer of montmorillonite. Reaction of montmorillonite with mono-functional silane coupling agent included two basic steps：first，the alkoxy group of coupling agent was hydrolyzed and silanol was generated in aqueous alcohol solution，then dehydration occurred to form silylated-montmorillonite between the silanol mentioned above and silanol distributed on the edge of montmorillonite at a high drying temperature. Cation exchange capacity (CEC) of montmorillonites kept the same as original montmorillonite after modification by coupling agent. Dispersion results in different solvents showed that the dispersibility of MMT was decreased in water，but was improved in toluene and ethanol. Accordingly the dispersibility of MMT in organic solvent could be increased after silanization by coupling agent.

Key words: silane coupling agent, montmorillonite, cation exchange capacity, dispersibility

摘要： 用单官能团硅烷偶联剂γ-氨丙基二甲基乙氧基硅烷（APMS）修饰蒙脱土（MMT）， IR 分析表明APMS通过化学键与蒙脱土键合。利用偶联剂上的氨基与水杨醛显色生成黄色希夫碱对404 nm处可见光的吸收特性进行定量测试，确定了蒙脱土可和偶联剂反应的活性硅羟基数目为29.6 mmol/(100gMMT)，最佳烘干温度为120 ℃。XRD结果说明蒙脱土的活性硅羟基分布在其端面不是在层间。推断出蒙脱土和单官能团硅烷偶联剂的反应分两步进行：偶联剂的烷氧基先在水醇溶液中水解生成硅醇，然后和蒙脱土端面上的硅羟基高温干燥脱水形成硅烷化蒙脱土。偶联剂修饰蒙脱土后其阳离子交换容量（CEC）不变，分散性实验显示硅烷化蒙脱土在水中的分散性变差，在甲苯和乙醇中的分散性提高，说明偶联剂的修饰提高了MMT在有机溶剂中的分散性。

关键词: 硅烷偶联剂, 蒙脱土, 阳离子交换容量, 分散性