CHARACTERIZATION OF CLAY MINERALS WITH SOME POLYMERIC MATERIALS

The adsorption of polymers at clay mineral surfaces has been reviewed. The adsorption or the interactionof Polymers to clay particles has been studied experimentally by a range of methods including adsorptionisotherms, infrared spectroscopy (IR), X-ray diffraction and nuclear magnetic resonance (NMR). The following review highlights the characterization of clay minerals with selected polymers of the chargedand uncharged type in an aqueous environment.The plateau of the isotherm provides interesting data on the quantity adsorbed at the monolayer, the partbefore the plateau supplies information on the adsorption mechanism. Adsorption of polymer on claysurface leads to a change in conformation in that the polymer. Polymer Conformation changes from arandom coil in solution to an extended form at the surface in which adsorbed polymer segments or trainsalternate with loops and tails extending away from the surface. X-ray diffraction is shown to be an excellent technique, of potentially widespread application, for determination of the orientation of polymer relative to a planer clay surface and can give some information on bonding interaction. IR is the most commonly reported method for estimating the fraction of segments attached to the surface. The method relies on a shift occurring in the IR adsorption band of a polymer segment, upon adsorption at clay surface. NMR has been shown to be a particularly useful technique for studying adsorbed polymers. It provides a microscopic probe of the polymer chain at the interface.