PPG Industries

About: PPG Industries is a company organization based out in Pittsburgh, Pennsylvania, United States. It is known for research contribution in the topics: Coating & Substrate (printing). The organization has 3947 authors who have published 5373 publications receiving 92154 citations. The organization is also known as: PPG Industries (United States).

Photochemical Activity of Nitrogen-Doped Rutile TiO2(110) in Visible Light

Abstract: TiO2(110) single crystals, doped with nitrogen via an NH3 treatment at 870 K, have been found to exhibit photoactivity at photon energies down to 2.4 eV, which is 0.6 eV below the band-gap energy for rutile TiO2. The active dopant state of the interstitial nitrogen that is responsible for this effect exhibits an N (1s) binding energy of 399.6 eV and is due to a form of nitrogen that is probably bound to hydrogen, which differs from the substitutional nitride state with an N (1s) binding energy of 396.7 eV. Optical absorption measurements also show enhanced absorption down to 2.4 eV for the NH3-treated TiO2(110). A co-doping effect between nitrogen and hydrogen is postulated to be responsible for the enhanced photoactivity of nitrogen-doped TiO2 materials in the range of visible light.

Water-reduced urethane coating compositions

Abstract: A water-diluted, ungelled, non-sedimenting polyurethane and a process for preparing such a polyurethane in an aqueous medium is disclosed. High molecular weight thermoplastic products are obtained by chain extending in aqueous medium an NCO polymer having a salt group equivalent weight of 6000 or less and substantially free of reactive hydrogen. The average functionality and equivalent ratio of the polyisocyanate and active hydrogen-containing materials used in making the NCO polymer, as well as the functionality of the chain extender, are carefully controlled so as to get high molecular weight ungelled products. Thermosetting compositions can be made by adding curing agent to the chain extended material. Curing agents can also be incorporated into the polymer molecule either in the making of the partially reacted NCO-containing prepolymer or by further reaction with the partially reacted NCO-containing prepolymer. The water-dispersed polyurethanes of the present invention are excellent film formers, capable of making coatings with a wide spectrum of desirable properties. In addition, they can be added to other water-compatible compositions to improve flexibility, hardness, drying and other coating properties.

Nucleophile-Initiated Thiol-Michael Reactions: Effect of Organocatalyst, Thiol, and Ene

Abstract: A detailed evaluation of the kinetics of the thiol-Michael reaction between hexanethiol and hexyl acrylate is described. It is shown that primary amines are more effective catalysts than either secondary or tertiary amines with, for example, quantitative conversion being achieved within 500 s in the case of hexylamine with an apparent rate constant of 53.4 mol L−1 s−1 at a catalyst loading of 0.057 mol %. Certain tertiary phosphines, and especially tri-n-propylphosphine and dimethylphenylphosphine, are shown to be even more effective species even at concentrations 2 orders of magnitude lower than employed for hexylamine and performed in solution with quantitative conversions reached within ca. 100 s for both species and apparent rate constants of 1810 and 431 mol L−1 s−1, respectively. The nature of the thiol is also demonstrated to be an important consideration with mercaptoglycolate and mercaptopropionate esters being significantly more reactive than hexanethiol with reactivity mirroring the pKa of the ...

An Experiment in Visual Scaling of Small Color Differences

Abstract: Under the auspices of the ISCC Committee on Color Difference Problems, an experiment was carried out in the visual scaling of small color differences involving six color microspaces. The object-color samples were visually evaluated by ranking, by subjective estimation, and by acceptability judgments. Visual scales were calculated by traditional procedures. Correlations were calculated between the visual scales and four color-difference formulas (CIELAB, C1ELUV, FMC-2, and FCM), and ellipsoids were optimized to the visual data. No fundamental differences were found between the results of the perceptibility judgments and the acceptability judgments. Higher correlations than reported for earlier comparable experiments were obtained between visual and calculated color differences.

Coating compositions having improved scratch resistance, coated substrates and methods related thereto

Abstract: Compositions are provided which contain (a) one or more polysiloxanes comprising at least one reactive functional group; a plurality of particles; and, optionally, one or more curing agents comprising at least one functional group that is reactive with any reactive functional group of polysiloxane (a). Additionally, a process for applying the multi-component composite coatings described above to a substrate and coated substrates are provided. A process for preparing the coating compositions also is provided. The multi-component composite coating compositions of the invention provide highly scratch resistant color-plus-clearcoatings capable of retaining scratch resistance after weathering.