THE PREPARATION AND CHARACTERIZATION OF ANION-CATION SURFACTANTS MODIFIED MONTMORILLONITE

A series of anion-cation surfactants modified organoclays were prepared by incorporating both cationic surfactant,hexadecyltrimethylammonium bromide(HDTMAB),and anionic surfactant,sodiumdodecyl sulfonate(SDS),to montmorillonites.A combination of elemental analysis,X-ray diffraction and thermogravimetric analysis was adopted to characterize the resulting organoclays.The organic carbon contents of the HDTMAB-SDS organoclays are further improved as compared with only HDTMAB modified organoclays.The XRD patterns showed that the basal spacings are expanded with the intercalation of surfactants.The characterization results indicated that SDS cannot be intercalated into montmorillonites whereas anionic surfactants can be transferred into the interlayer of montmorillonite by pre-modification with cationic surfactants.In derivative thermogravimetric curves,a new peak is displayed,which is located at 400-430 °C.This is related to forming composites with enhanced thermal stability.