Structure and performance of anionic–cationic-organo-montmorillonite in different organic solvents

Abstract

Montmorillonite (Mt) was modified in aqueous solution by cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfonate (SDS) under ultrasonic conditions at 60 °C. Anionic–cationic-organo-montmorillonite (ACOMt) was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and contact angle measurement. The results indicated that ACOMt was prepared successfully, and the polar property of ACOMt was higher than that of cationic-organo-montmorillonite (COMt). The results of SEM proved that there were great amounts of loose and thin platelets of ACOMt. In addition, the properties of ACOMt in three organic solvents were investigated using XRD, SEM, optical microscopy and viscometry, etc. The results of the XRD patterns demonstrated that the basal spacing of ACOMt became small because of parts of the surfactants getting out of the interlayer after being dispersed in the organic solvents. Moreover, with the increase in the solvent polarity, the amounts of surfactants getting out of the interlayer increased. The results of optical microscopy revealed that, with the increase of surfactants and the polar property, the dispersibility of powdery samples in the organic solvents improved and ACOMt in a highly polar solvent showed the best dispersibility. However, the results of SEM indicated that the morphology of ACOMt dispersed in three organic solvents was not significantly different. Meanwhile, dispersion of ACOMt in xylene exhibited the best thixotropic properties and apparent viscosity.