蛭石的结构修饰及有机插层试验

用酸处理+热处理+钠化综合法,对蛭石进行了结构修饰改性,得到具有低剩余层电荷的改性蛭石.用十六烷基三甲基溴化铵(HDTMAB)对改性蛭石进行了有机插层试验,并与未改性蛭石原样的插层试验进行对比,以研究结构修饰及剩余层电荷变化对其有机插层的影响.结果表明,由于剩余层电荷的降低,十六烷基三甲基溴化铵在改性蛭石层间的插层量和排列方式与在蛭石原样中不同,当HDTMAB用量小于5倍数CEC时,进入层间域的HDTMAB数量少,呈倾角较小的单层倾斜排列,蛭石层间距小,有序度低;当HDTMAB用量等于5.0倍CEC时,HDTMAB在蛭石层间以双层倾斜方式排列,层间距与有机插层蛭石原样相当;当HDTMAB用量达到10.0倍CEC时,蛭石层间以双层倾斜排列的HDTMAB倾角增大,层间距较同样条件下插层的蛭石原样更大,而且大部分蛭石已层剥离.因此,结构修饰有利于制备聚合物/蛭石纳米复合材料.

Structure Modification and Organic Intercalation of Vermiculite

A vermiculite ore from Chengde, China was modified by the combination of acid treatment, heat treatment and Na ion exchange. Diverse amounts of HDTMAB, equivalent to 1, 1.5, 2, 3, 5 and 10 times of the ore's CEC, respectively, were used for the organic intercalation of the modified and crude vermiculites for comparison. XRD analysis and CEC measurement show that after the organic intercalation of modified vermiculite, the structure is different from that of crude vermiculite because modified vermiculite has lower CEC and hence weaker structure layer linkage. The modified vermiculite with smaller interlayer spacing is obtained when the amount of HDTMAB used for the intercalation is less than 5 times of the CEC of the crude vermiculite. When the amount of HDTMAB used is 5 times of the CEC of the crude vermiculite, the interlayer spacing of the modified vermiculite is equivalent to that of the crude vermiculite intercalated under the same condition. The modified vermiculite with larger interlayer spacing and even exfoliation can be obtained when the amount of HDTMAB used is 10 times of the CEC of the crude vermiculite, which is of importance to the preparation of polymer/vermiculite nanocomposites.