Structure and swelling of polymer-clay composites

Abstract

Composition gels on the basis of bentonite clay of Manrak deposit (East-Kazakhstan region) and nonionogenic polymers -poly-2-hydroxyethyl-acrylate and polyacrylamide were synthesized by radical intercalative polymerization in situ with various content o f cross-linking agent N,N-methylene-bisacrylamide and with time of intercalation about 8 hours. The morphological structure, the nature of interaction of components and the swelling ability of composition gels were studied by scanner electron microscopy, equilibrium swelling and IR-spectroscopy methods. By studying of morphological structure it was determined, that the polymer-clay composition gels, synthesized by intercalative polymerization, are most homogenous and interconsistency in case of "acrylamide-clay" composition in contrast with "2-hydroxyethylacrylate -clay" composition. For "acrylamide-clay" gels the swelling degree of gels was stated to decrease with the increase in the content of cross-linking agent and ionic strength, but "2-hydroxyethylacrylate -clay" compositions have the extremely character of swelling, where maximum degree of swelling account for gel with content of cross-linking agent 1*10 -2 М. Interaction of composition components was realized on account of hydrogen bonds with formation of chemically cross-linked complex polymer-clay. Decrease of swelling degree of compositions in physiological solution points to acquisition of polyelectrolyte nature of composition gels on account of combination of nonionogenic macromolecules of polymers with negatively charged particles of bentonite clay. For intercalated samples of polymer-clay compositions, the degree of swelling at all degrees of cross-linking is between those for pure polymers and pure clay, that in turn, agrees with the conclusion on the great composition homogeneity of samples with preliminary intercalation. As of results of holding investigation fit is safe to say, that obtained polymer-clay composition gels are potential sorbents and prolongated carriers of medicines.

Interactions of bentonite clay in composite gels of non-ionic polymers with cationic surfactants and heavy metal ions

“…Therefore, the radical intercalation polymerization in situ of monomers on the surface of clay platelets is of special interest, resulting in a homogeneous material with uniform distribution of the mineral throughout the volume of the polymer matrix [20]. It is already well established that bentonite clay (BC) can be embedded into a hydrogel by in situ radical polymerization of nonionic monomers [21][22][23].…”