Incorporation of poly(acrylic acid), poly(vinylsulfonate) and poly(styrenesulfonate) within layered double hydroxides

Abstract

Poly(acrylic acid), poly(vinylsulfonate) and poly(styrenesulfonate) have been incorporated between the positively charged sheets of layered double hydroxides (LDHs)M_1–xAl_x(OH)₂⁺(M = Mg, Ca, Co) and Zn_1–xM′_x(OH)₂⁺(M′= Al, Cr) to form layered nanocomposites. The resulting nanocomposites contained the LDH sheet structures separated by 7.6–16.0 Å, which is sufficient to accommodate polymer bilayers between the LDH sheets. Preparations were carried out in deaerated aqueous base by a template reaction, involving the formation and precipitation of nanocomposites from metal nitrate-salt precursors in the presence of the dissolved polymer. Structural and compositional details were provided by X-ray diffraction (XRD), FTIR spectroscopy, elemental analysis, differential scanning calorimetry (DSC) and thermogravimetry (TG). Scanning electron microscopy (SEM) indicates that the nanocomposition of LDHs with ionomers significantly alters the particle microstructure from that of the LDH carbonates derived from aqueous precipitation.