Clay minerals nonswelling mineral

The third class of polymers contains one or more nitrogen atoms on a pendant sidechain in the polymer repeat unit (13,14). The nitrogen may or may not be quaternary. In addition to being swelling clay stabilizers, these polymers also stabilize nonswelling mineral fine particles. Limited molecular weight data ig available but molecular weight values from 50,000 to 1 X 10 daltons have been cited for various polymers. 

The sorption of alkaline and earth-alkaline cations on expandable three-layer clays—smectites (montmorillonites)—can usually be interpreted as stoichiometric exchange of interlayer ions. Heavy metals, however, are sorbed by surface complex formation to the OH functional groups of the outer surface (the so-called broken bonds). The nonswellable three-layer silicates, micas such as illite, usually can not exchange their interlayer ions but the outside of these minerals and the weathered crystal edges ( frayed edges ) participate in ion exchange reactions. 

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