Dispersion of organically modified clays within n-alcohols

A method for formation of polymer-clay nanocomposites involves dispersion of the nanometer silicate layers of clays into a solvent, followed by dispersion into polymers. The dispersion of layered silicates within solvents affects the structure and properties of the nanocomposites. We report the dispersion of organically modified clays, used for formation of nanocomposites with organic polymers, within a range of alcohol solvents. Experiments involved stirring a mixture containing approximately 1 wt% of alkylammonium-modified clays in n-alcohols with general molecular structure RnOH, where n represents the number of carbons of alkyl chains, varying from 2 to 8. The clays precipitated from the dispersion when RnOH solvents with n<5 were used, however, they formed gels for solvents with n5. The increased dispersion was related to the decrease of polarity and hydrogen bonding force within solvents. X-ray diffraction for the dispersed clays indicated that the interlayer spaces (1.8 nm), formed by regular stacking of the silicate layers, expanded to a maximum of 3.0 nm after treatment with RnOH with n5. The interlayer expansion was due to the intercalation of n-alcohol molecules within the interlayer spaces. It is suggested that the alkyl chains of n-alcohols remain parallel to the silicate surface in the intercalate. Preliminary experiments on the influence of these alcohol solvents on the intercalation of polyol (polyether) are also reported.