Abstract: Bentonite was modified by two novel bis-quaternary ammonium salts: hexamethyl propyl diammonium methylsulfate (PDAS) and hexamethyl butyl diammonium methylsulfate (BDAS). The microstructures of the organobentonites were characterized in terms of Infrared spectral (FT-IR), X-ray diffraction (XRD), differential thermogravimetry (DTG) and electron microscopy (SEM and TEM). The results show that basal spacings of organobentonites modified by PDAS and BDAS are 1.380 nm and 1.413 nm respectively, both of bis-quaternary ammonium salts are arranged in monolayers only among the interlayers of bentonite. Compared with one-step decomposition of BDAS, PDAS was decomposed by two steps within the bentonite galleries, and their onset decomposition temperatures and temperatures corresponds to the maximum mass loss rate (tpeak) is higher than their solid bis-quaternary ammonium salts by 15, 30 ℃ and 30, 80 ℃. Particle sizes and aggregation of organobentonites modified by PDAS are quietly different from those modified by BDAS.

Key words: Bis-quaternary ammonium salts, Spacer, Organobentonite, Modified, Characterization

摘要： 以六甲基丙二铵二甲硫酸盐（PDAS）和六甲基丁二铵二甲硫酸盐（BDAS）为改性剂制备奇偶间隔基短链双季铵有机膨润土，通过X-射线衍射（XRD）、红外光谱（FT-IR）、热分析（TG）和电镜（SEM/TEM）等手段表征其结构。结果表明，PDAS和BDAS改性膨润土层间距分别为1.380 nm和1.413 nm，两种双季铵盐在层间只能以单层平卧的方式排列；有机膨润土中，PDAS是分步分解的，BDAS是一步分解，PDAS和BDAS的开始热分解温度和最大质量损失率对应温度（tpeak）相比其季铵盐固体分别提高了15，30 ℃和30，80 ℃；PDAS和BDAS有机膨润土的表面形貌有明显差异。

关键词: 双季铵盐 , 奇偶间隔基 , 有机膨润土 , 改性 , 表征