Published online by Cambridge University Press: 15 February 2011
Nano-composites have been prepared from Na+ and Ca++ montmorillonite (MMT) in a polystyrene matrix via chemical intercalation. Vinyl monomer-g-MMT was prepared by exchanging the mineral cation by vinylbenzyl trimethylammonium chloride, thus rendering the mineral organophilic and forming polymerizable moieties directly bonded to the lamellar surface of the mineral. Styrene was added and polymerized by free radical in selected solvents. The ratio of mineral to the bound polymer ranged from 0.3 to 1.25 (by weight) depending on the initial mineral concentration in the feed and on the solvent used. The mineral domains in the composite, measured from suspension cast film fall in the range of 150 nm to 400 nm. Measured from compression molded samples, the domains were ca. 50 nm which is much smaller than the mineral aggregate and comparable to that of the primary particle of the mineral. WAXD disclosed that the d (001) spacing of MMT in the composite ranged from 1.7 to 2.5 nm suggesting that the mineral aggregates (ca. 10 μm) were dissociated into individual layers then reassembled into lamellar nanoclusters.