Preparation of Organic−Inorganic Nanocomposites with a Layered Titanate

Layered nanocomposites with poly(ethylene oxide), PEO, and poly(vinylpyrrolidone), PVP, incorporated between H x Ti 2 - x /4 □ x /4 O 4 (□ = 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-μm diameter platelets, much larger than those of 0.1−1 μm 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 °C, polymer degradation and structure decomposition between 200 and 450 °C, and a titanate phase change above 450 °C. Elemental analyses give empirical formulas of H 0.7 Ti 1.83 O 4 (C 2 H 4 O) 1.54 (H 2 O) 1.28 and H 0.7 Ti 1.83 O 4 (C 16 H 36 N) 0.05 (C 6 H 9 NO) 1.22 (H 2 O) 0.92 for the PEO and PVP nanocomposites, respectively. These results are compared with those obtained for other layered nanocomposites.