Xerogels
Mostrando 1-12 de 19 artigos, teses e dissertações.
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1. Polyurethane /Ionic Silica Xerogel Composites for CO2 Capture
Capturing carbon dioxide (CO2) from exhaust gases is an important strategy to prevent climate change. There is a great interest in developing novel CO2 sorbents. Thus, a series of polyurethane (PU) / silica xerogels functionalized with RTILs (bmim Cl and bmim TF2N) composites were prepared and characterized. PU matrix was reinforced with functionalized silic
Mat. Res.. Publicado em: 16/09/2019
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2. THE USE OF POLYSACCHARIDES EXTRACTED FROM SEED OF Persea americana var. Hass ON THE SYNTHESIS OF ACRYLIC HYDROGELS
This paper reports the use of polysaccharides extracted from seed of Persea americana var. Hass in the synthesis of acrylic hydrogels. The effects of the chemical composition (acrylamide/acrylic acid), the concentration of crosslinking agent (glycerol diacrylate) and the type of initiation (redox, photoinitiation) of the hydrogels were evaluated with and wit
Quím. Nova. Publicado em: 2018-02
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3. Time domain NMR evaluation of poly(vinyl alcohol) xerogels
Abstract Poly(vinyl alcohol) (PVA)-based chemically cross-linked xerogels, both neat and loaded with nanoparticulate hydrophilic silica (SiO2), were obtained and characterized mainly through time domain NMR experiments (TD-NMR). Fourier-transform infrared (FT-IR) and wide angle X-ray diffraction (WAXD) analyses were employed as secondary methods. TD-NMR, thr
Polímeros. Publicado em: 08/08/2016
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4. NIR Luminescence from Sol-Gel Er3+ Doped SiO2:GeO2 Transparent Gels, Nanostructured Powders and Thin Films for Photonic Applications
Samples of (1 – x)SiO2:xGeO2 compositions, containing x = 10 and 20, and doped with Er3+, were prepared by a simple sol-gel route. Homogeneous and transparent gels were synthesized and xerogels were obtained by gel annealing from 700 ºC to 1100 ºC. Films exhibiting high transmittance in the visible and near infrared were deposited by spin-coating techniq
J. Braz. Chem. Soc.. Publicado em: 2015-12
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5. ESTUDO DA IMOBILIZAÇÃO DE LIPASE EM SÍLICA OBTIDA PELA TÉCNICA SOL-GEL
The objective of this work was the immobilization of the enzyme Candida antarctica lipase B (CAL B) using the sol-gel method of immobilization and three different initiators of the polymerization reaction: one acid (HCl), one basic (NH4OH) and the other nucleophilic (HBr). Tetraethylorthosilicate was used as the silica precursor. The influence of the additiv
Quím. Nova. Publicado em: 2015-03
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6. Materiais híbridos orgânico-inorgânicos (ormosil) obtidos por sol-gel com potencial uso como filtro solar
This work aimed at the synthesis and characterization of particles of modified silica containing the organic filter dibenzoylmethane (DBM) by the hydrolytic sol-gel method, with modifications to the Stöber route. The structures of the resulting Xerogels were characterized by diffuse reflectance UV-VIS spectroscopy in the solid state, infrared absorption spe
Química Nova. Publicado em: 2011
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7. Synthesis of silica xerogels with high surface area using acetic acid as catalyst
Nesse trabalho foi estudada a influência do ácido acético na estrutura de poros e na área superficial de sílicas preparadas pelo método sol-gel. Condições experimentais de síntese, tais como temperatura de policondensação e solventes, também foram estudadas. Isotermas de adsorção de N2 das amostras foram classificadas como do tipo 1, típicas d
Publicado em: 2010
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8. USE OF RICE HUSKS FOR THE PRODUCTION OF XYLITOL AND SILICA XEROGEL / APROVEITAMENTO DA CASCA DE ARROZ PARA A PRODUÇÃO DE XILITOL E SÍLICA XEROGEL
The generation of residual materials and its unavoidable disposal in the environment has been a reason of great concern, not only environmentally but also economically. The use of these renewable residual feedstocks, not only for the production of heat and energy, but also for the generation of technological products, has become a priority. In this study, it
Publicado em: 2009
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9. Estudo de complexos fotocrômicos de xerogéis de ormosil através de ressonância magnética nuclear em estado sólido / Photochromic Complexes of Ormosil Xerogels Studied by Solid-State Nuclear Magnetic Resonance
Fotocromismo refere-se ao fenômeno reversível no qual um material altera sua coloração quando irradiado com luz. Neste trabalho, é analisada a estrutura de materiais híbridos formada por poliânions de ácido 12-tungstofosfórico (H3PW12O40, HPW) HPW) inseridos em uma matriz de silicatos orgânico-inorgânica (ormosil). Estes materiais apresentam ativi
Publicado em: 2009
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10. Hybrid metal-organic nanocomposites based on vandium pentoxide / Nanocompósitos híbridos metal-orgânicos baseados em pentóxido de vanádio
Nanostructured systems based on the intercalation of molecular and supramolecular species into lamellar vanadium pentoxide xerogels are focused on this Thesis. The exciting characteristics of the supramolecular systems which are closely related to the nature, interaction and organization of the chemical species involved, have been exploited aiming their appl
Publicado em: 2008
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11. Efeito da matriz no comportamento fotocrômico de ormosils de fosfotungstato / Matriz effect in photochromic behavior of phosphotungstate ormosils
Esta dissertação versa sobre o estudo de filmes híbridos orgânicos-inorgânicos do tipo ormosil com heteropoliânions do tipo Keggin. O heteropoliânion usado nesse trabalho foi: H3PW12O40 enquanto o ormosil foi obtido a partir do processo sol-gel usando tetraetilortossilicato (TEOS) como agente formador da rede 3D de silicatos e organossilanos contendo
Publicado em: 2008
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12. Synthesis of silica xerogels with high surface area using acetic acid as catalyst
Nesse trabalho foi estudada a influência do ácido acético na estrutura de poros e na área superficial de sílicas preparadas pelo método sol-gel. Condições experimentais de síntese, tais como temperatura de policondensação e solventes, também foram estudadas. Isotermas de adsorção de N2 das amostras foram classificadas como do tipo 1, típicas d
Journal of the Brazilian Chemical Society. Publicado em: 2007