Characterization of Rheology, Electrokinetic Properties, and Surface Micromorphology of DTABr-MMT and CPBr-MMT Organoclays

Abstract

In this study, the characterization of sodium-activated montmorillonite (NaMMT) dispersions (2 wt%) are examined in detail using rheological parameters, such as viscosity, yield value, apparent and plastic viscosity, and electrokinetic parameters, such as mobility and zeta potentials. Besides, the influence of solid content on viscosity is also evaluated. Dodecyltrimethylammonium bromide (DTABr) and cetylpyridinium bromide (CPBr) cationic surfactants are added to the NaMMT dispersions in different concentrations in the range of 10 3-5 10 2 mol/L. The rheological and electrokinetic properties, and the morphology of the organoclays (DTABr-NaMMT and CPBr-NaMMT) prepared with surfactants are compared in detail. Atomic force microscopy (AFM) techniques are used to characterize the morphology of NaMMT before and after intercalation of DTABr and CPBr surfactants. The intercalation of the surfactants in NaMMT dispersion has been studied by X-ray diffraction to examine whether the interlayer spacing swells or not. The basal spacings have been changed with the alkyl chain length of the surfactants. The morphology of bentonite dispersions is analyzed by scanning electron microscopy.