Organoclay is an organically modified
phyllosilicate
Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust.
In mineralogy, silica (silicon dioxide, ) is usually consid ...
, derived from a naturally occurring
clay mineral. By exchanging the original interlayer cations for organocations (typically quaternary alkylammonium ions) an organophilic surface is generated, consisting of
covalently
A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atom ...
linked organic moieties. The lamellar structure remains analogous to the parent phyllosilicate.
Separation of the layers due to ion exchange, from the initial interlayer spacing of as little as 3 Å in the case of Na+ cations to the distances in the range of 10–40 Å as well as the change of chemical character of the clay surface, allows the in-situ polymerization or mixing with certain polymers to obtain what is known as nanocomposite. When ordered aluminosilicate sheets are lying parallel to each other, separated with polymer chains of certain type, the system is classified as intercalated nanocomposite. If separation of the layers is so significant, that they are no longer lying opposite to one another, but randomly ordered, then one get the exfoliated nanocomposite.
Applications
Owing to its large surface area together with hydrophobic chains emerging from the clay surface, organoclay can be used to remove oil from water. It is also applied as a component in
paint formulations or as a viscosifier for oil-based
drilling fluid
In geotechnical engineering, drilling fluid, also called drilling mud, is used to aid the drilling of boreholes into the earth. Often used while drilling oil and natural gas wells and on exploration drilling rigs, drilling fluids are als ...
s.
It can be used in polymer chemistry as a nucleating agent.
References
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Phyllosilicates