Metal oxide-polymer composites

A method of making metal oxide clusters in a single stage by reacting a metal oxide with a substoichiometric amount of an acid in the presence of an oxide particle growth terminator and solubilizer. A method of making a ceramer is also disclosed in which the metal oxide clusters are reacted with a functionalized polymer. The resultant metal oxide clusters and ceramers are also disclosed

Metal oxide-polymer composites

A method of making metal oxide clusters in a single stage by reacting a metal oxide with a substoichiometric amount of an acid in the presence of an oxide particle growth terminator and solubilizer. A method of making a ceramer is also disclosed in which the metal oxide clusters are reacted with a functionalized polymer. The resultant metal oxide clusters and ceramers are also disclosed

Nanocomposites and methods for synthesis and use thereof

Nanocomposite compositions and methods of synthesis of the compositions are described. In particular, liquid crystal-functionalized nanoparticles, liquid crystal-templated nanoparticles, nanocomposite compositions including the nanoparticles, and composite compositions including the nanocomposites are detailed.Board of Regents, University of Texas Syste

Corrosion Protection of at Alloys by Solution Cast Ta₂O₅

AbstractA newly developed amorphous, corrosion resistant Ta2O5 coating in saturated H2/H2O/Cl2 environment was studied by scanning and transmission electron microscopy and surface spectroscopy. Although Ta2O5 films formed on polished Al single crystal surfaces by sputter deposition of Ta and subsequent anodization effectively prevent the Al from corrosion by water saturated with chlorine, Al alloy surfaces are not protected, since the anodic film formed over grain boundaries, processing lines, and emergent Precipitates is poorly adherent, thus providing loci for corrosion. This problem was eliminated by casting a 400Å layer of tantalum oxyhydroxide polymer from ethanol solution onto the Al alloy substrate and curing to a Ta2O5 layer that effectively resisted attack by wet chlorine.</jats:p

Ductile Tantalum Oxide Protective Coatings

AbstractAmorphous, anodic Ta2O5 films of 400 A thickness deposited on deformable polymer substrates deformed by microshear banding even at 5–10% tensile strain. Electron beam evaporated Ta2O5 (EBE) were considerably more brittle in tension on the same substrates, fracturing at strains less than 1%. Even though both films were amorphous to electron diffraction the EBE vibrational spectrum in the Ta2O5 region (900 cm-1 - 400 cm-1) was more reminiscent of thermally oxidized material that appears to have greater microstructural order. A significant dynamic mechanical peak was observed at 60–90°C for both Al and Ta foils coated with either anodic or EBE Ta2O5 films. This process was assigned to relaxation of interfacial stresses induced by atomic motion in the oxide in this temperature range. In the face of the rather similar dynamic mechanical spectra we suspect that the presence of a greater Packing heterogeneity might explain the greater brittleness of the EBE films.</jats:p

Investigation of Thermal-Induced Changes in Molecular Order on Photopolymerization and Performance Properties of a Nematic Liquid-Crystal Diacrylate

Polymerization shrinkage and associated stresses are the main reasons for dental restorative failure. We developed a series of liquid crystal diacrylates and dimethacrylates which have markedly low polymerization shrinkage. In order to fully understand the effects of temperature-induced changes of molecular order on the photopolymerization process and performance properties of the generated polymers, the photopolymerization of a difunctional acrylate, 2-t-butyl-1,4-phenylene bis (4-(6-(acryloyloxy)hexyloxy)benzoate), which exists in the nematic liquid crystalline phase at room temperature, was investigated as a function of photopolymerization temperature over the nematic to isotropic range. Morphological studies suggested that a mesogenic phase was immediately formed in the polymer even if polymerization in thin films occurred above the nematic-to-isotropic (N&rarr;I) transition temperature of the monomer (Tn-i = 45.8 &deg;C). Dynamic mechanical analysis of 2 &times; 2 mm cross-section bar samples polymerized at 60 &deg;C showed reduced elastic moduli, increased glass transition temperature and formation of a more crosslinked network, in comparison to polymers formed at lower polymerization temperatures. Fractography analysis showed that polymers generated from the nematic liquid crystalline phase underwent a different fracture pattern in comparison to those generated from the isotropic phase. Volumetric shrinkage (2.2%) found in polymer polymerized from the nematic liquid crystalline phase at room temperature was substantially less than the 6.0% observed in polymer polymerized from an initial isotropic phase at 60 &deg;C, indicating that an organized monomer can greatly contribute to reducing cure shrinkage

Investigation of Thermal-Induced Changes in Molecular Order on Photopolymerization and Performance Properties of a Nematic Liquid-Crystal Diacrylate

Polymerization shrinkage and associated stresses are the main reasons for dental restorative failure. We developed a series of liquid crystal diacrylates and dimethacrylates which have markedly low polymerization shrinkage. In order to fully understand the effects of temperature-induced changes of molecular order on the photopolymerization process and performance properties of the generated polymers, the photopolymerization of a difunctional acrylate, 2-t-butyl-1,4-phenylene bis (4-(6-(acryloyloxy)hexyloxy)benzoate), which exists in the nematic liquid crystalline phase at room temperature, was investigated as a function of photopolymerization temperature over the nematic to isotropic range. Morphological studies suggested that a mesogenic phase was immediately formed in the polymer even if polymerization in thin films occurred above the nematic-to-isotropic (N→I) transition temperature of the monomer (Tn-i = 45.8 °C). Dynamic mechanical analysis of 2 × 2 mm cross-section bar samples polymerized at 60 °C showed reduced elastic moduli, increased glass transition temperature and formation of a more crosslinked network, in comparison to polymers formed at lower polymerization temperatures. Fractography analysis showed that polymers generated from the nematic liquid crystalline phase underwent a different fracture pattern in comparison to those generated from the isotropic phase. Volumetric shrinkage (2.2%) found in polymer polymerized from the nematic liquid crystalline phase at room temperature was substantially less than the 6.0% observed in polymer polymerized from an initial isotropic phase at 60 °C, indicating that an organized monomer can greatly contribute to reducing cure shrinkage.</jats:p