Enhanced intercalation of organo-muscovite prepared via hydrothermal reaction at low temperature

Abstract

Muscovite clay is an ideal reinforcing filler due to its high-aspect ratio. However, it does not swell in water, making it hard to be treated and intercalated. In this study, ion exchange treatment is carried out on muscovite clay using cetyltrimethylammonium bromide (CTAB) cations via two-step intercalation method. The intercalation steps included: inorganic–inorganic ion exchange treatment and inorganic–organic ion exchange treatment under hydrothermal conditions. The intercalation of muscovite particles was examined with various techniques to analyse the physical and chemical changes. Furthermore, the hydrothermal conditions for effective $\hbox {CTA}^{+}$ ion intercalation within muscovite interlayers prepared via the hydrothermal process at low temperature, $180{^{\circ }}\hbox {C}$, under different hydrothermal reaction times and CTAB/Li-Mus mass ratio were investigated. Fourier transform infra-red (FTIR) analysis revealed that the $\hbox {CTA}^{+}$ ions are diffused into the interlayers of aluminosilicate and formed a strong electrostatic bond with the clay surface. X-ray powder diffraction analysis showed that the interplanar spacing in the organo-muscovite samples is almost identical as the hydrothermal reaction time is prolonged beyond 12 h. An optimum limit of the CTAB to Li-Mus ratio is observed as the $d_{002}$ plane spacing is increased with an increase of the mass ratio of CTAB to Li-Mus up to 1.0 C and decreased with a further increase in the mass ratio. In addition, the intercalated $\hbox {CTA}^{+}$ chains are homogenously distributed and formed a paraffin-like arrangement in the muscovite clay. Besides, the structure of aluminosilicate layers is not affected or damaged after both treatments according to FTIR analysis.