Hydrothermal method is proposed to synthesize non-expandable muscovite to become expandable clay minerals through two stages ion-exchange process. The modified muscovite known as organomuscovite (OM) is important in the design and the implementation of organoclay based materials in industry.
The surface treatment of muscovite has been challenging due to its non-expandable properties. Hence, this further implies that muscovite will not swell and the interlayer cations cannot be exchanged under ordinary conditions. This is due to the isomorphic substitution of Al3+ ions for Si4+ ion at tetrahedral sites in muscovite. The resulting excess negative charge is balanced by non-hydrated potassium ion, creating a strong electrostatic force between the layers. Muscovite is believed to be non-exchangeable, with inherent expansion, and incompatible with most of the polymer systems
Molecular structure of muscovite containing exchangeable potassium ion, K+, and (b) Schematic representation of side view between layer.
Modification of muscovite’s surface is required to enlarge the basal spacing and improve the compatibility with polymer matrices. The changes in basal spacing indicate the organic surfactant has been intercalated within the interlayer of organoclay. Surface treatment of muscovite with various concentration of CTAB was investigated. The chemical modification of the muscovite surface layers warrants further study in the view of producing a new class of layered silicate nanocomposites.
Modification procedure of muscovite in the aqueous solution of CTAB
1. Che Ismail, N. H.; Ahmad Bakhtiar, N. S. A.; Md. Akil, H. Chem. Phys. 2017, 196, 324.