Preparation of organic-inorganic nanocomposites with a layered titanate

Layered nanocomposites with poly(ethylene oxide), PEG, and poly(vinylpyrrolidone), PVP, incorporated between H(x)Ti(2-x/4)square O-x/4(4) (square = Ti vacancy) titanate layers, are synthesized from a colloidal titanate suspension obtained by exfoliation in aqueous tetrabutylammonium hydroxide and subsequent acidification, Products are characterized by powder X-ray diffraction, thermal analyses, FTIR spectroscopy, scanning electron microscopy, and elemental analysis. Interlayer expansions for the vacuum-dried nanocomposites are 0.81 and 2.2 nm for the PEO- and PVP-containing products, respectively. Both nanocomposites are comprised of 10-100-mum diameter platelets, much larger than those of 0.1-1 mum for the starting titanate. FTIR spectra indicate the presence of the polymers and suggest decreased water interaction with titanate sheet surfaces for the polymer-containing products. Thermal analyses of nanocomposites show intercalate water loss below 200 degreesC, polymer degradation and structure decomposition between 200 and 450 degreesC, and a titanate phase change above 450 degreesC. Elemental analyses give empirical formulas of H0.7Ti1.83O4(C2H4O)(1.54)-(H2O)(1.28) and H0.7Ti1.83O4(C16H36N)(0.05)(C6H9NO)(1.22)(H2O)(0.92) for the PEO and PVP nanocomposites, respectively. These results are compared with those obtained for other layered nanocomposites.