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.