Polymeric Precursors
Mostrando 1-12 de 41 artigos, teses e dissertações.
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1. Mixed Electrical Conduction of Calcium Aluminates Synthesized by Polymeric Precursors
A study of the electrical transport properties of calcium aluminate (CA) with coexisting C3A and C12A7 phases was carried out. In this work, powders resulting from synthesis based on the polymer precursor method. The resulting product was characterized by means of XRD, Raman, and UV-visible analysis to obtain the optical BG and by EIS. From the XRD and Raman
Mat. Res.. Publicado em: 23/11/2018
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2. Gas-Phase Conversion of Glycerol to Acetol: Influence of Support Acidity on the Catalytic Stability and Copper Surface Properties on the Activity
Mesoporous mixed copper-aluminum oxides and copper-silicon oxides were synthesized with polymeric precursors route in order to evaluate the effect of the support acidity on the catalytic stability due to the carbon deposit and the copper surface characteristics on the catalytic activity for the gas-phase conversion of glycerol to acetol. The samples were cha
J. Braz. Chem. Soc.. Publicado em: 2016-12
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3. Synthesis and Structural Properties of Niobium Pentoxide Powders: A Comparative Study of the Growth Process
Powders Nb2 O5 were prepared by two different synthesis method, Sol-Gel and polymeric precursors (Pechini). In the Pechini method before adding the citric acid in the process, four different solutions were used to get the samples. For Sol-gel method, two different processes were also used in obtaining powders. The precursor was completely solubilized in etha
Mat. Res.. Publicado em: 10/10/2016
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4. Kinetic Investigation of Thermal Formation Processes of SiOC Glasses Derived from C-Containing Hybrid Polymeric Networks
In this study, hybrid polymeric networks were prepared by hydrosilylation reaction as precursors to silicon oxycarbide (SiOC) glass. The polymeric networks were prepared from poly(methylsiloxane) (PMS) and divinylbenzene (DVB) in the 80:20 and 20:80 (PMS/DVB) compositions, with or without activated charcoal (AC), which was used as additional carbon source. F
J. Braz. Chem. Soc.. Publicado em: 2015-05
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5. New Flexible and Transparent Solution-Based Germanium-Sulfide Polymeric Materials
New flexible and transparent materials based on germanium sulfide were obtained using GeCl4 and 1,3-propanedithiol as precursors. These materials have transparency in the ultraviolet-visible (UV-Vis) spectral region (about 70%), thermal stability up to 200 °C and glass transition located at temperatures below 0 °C (-37 °C, -56 °C and -59 °C) as shown by
J. Braz. Chem. Soc.. Publicado em: 2015-05
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6. Caracterização térmica e estrutural de pós e filmes finos de BaTiO3 sintetizados via método Pechini / Thermal and structural characterization of powders and thin films of BaTiO3 synthesized by Pechini method
Amorphous oxides are chemical compositions whose atomic or molecular configuration does not follow a periodicity like it happens with crystals, which are essentially constituted by oxygen atoms, which has to be the most electronegative element, and other elements. The barium titanate (BaTiO3), amorphous oxide obtained through this work has tetragonal structu
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/02/2012
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7. Sulfonation and characterization of styrene-indene copolymers for the development of proton conducting polymer membranes
The aim of this work is to obtain polymer precursors based on styrene copolymers with distinct degrees of sulfonation, as an alternative material for fuel cell membranes. Acetyl sulfate was used to carry out the sulfonation and the performance of the polyelectrolyte was evaluated based on the content of acid polar groups incorporated into the macromolecular
Polímeros. Publicado em: 30/10/2012
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8. Development of plurimetallic electrocatalysts prepared by decomposition of polymeric precursors for EtOH/O2 fuel cell
Este trabalho teve como objetivo desenvolver eletrocatalisadores plurimetálicos contendo Pt, Ru, Ni e Sn suportados em C pelo método de decomposição de precursores poliméricos (DPP), na razão metal:carbono de 40:60% em massa, para aplicação em célula a combustível de etanol direta (DEFC). As nanopartículas obtidas foram caracterizadas físico-quim
Journal of the Brazilian Chemical Society. Publicado em: 2012-03
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9. DESENVOLVIMENTO DE CATALISADORES A BASE DE NÍQUEL COM ESTRUTURA PEROVSQUITA PARA A UTILIZAÇÃO NA PRODUÇÃO DE GÁS DE SÍNTESE.
Nickel-based catalysts with perovskite like structure have shown promising application in several catalytic reactions such as in the partial oxidation of methane to obtain syngas (H2 + CO). However, these properties are potentially influenced by synthesis methods, calcinations conditions (temperature, time and atmosphere) and substitutions of sites A and/or
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/03/2011
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10. Nano-Ceramic Inorganic Pigments Synthesis for Route Polymeric Precursors / Síntese de pigmentos cerâmicos inorgânicos nanométricos pela rota dos precursores poliméricos
Considerando a evolução tecnológica em constante crescimento e a necessidade de técnicas de produção na área de cerâmica que avancem em conjunto, buscou-se neste estudo, a pesquisa e desenvolvimento do método dos precursores poliméricos para obtenção de pigmentos cerâmicos inorgânicos. Método que proporciona qualidade a obtenção dos pós pre
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 08/02/2011
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11. Development and characterization of a novel bioresorbable and bioactive biomaterial based on polyvinyl acetate, calcium carbonate and coralline hydroxyapatite
Coralina® HAP-200 (coralline hydroxyapatite obtained by hydrothermal treatment of marine corals) and POVIAC® (polymeric matrix based on PVAc), commercial trade marks were mixed with a natural product from the Cuban sea costs, i.e. calcium carbonate from Porites Porites coral, to obtain a novel bioactive composite with potential use as bone restoration mate
Materials Research. Publicado em: 18/03/2011
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12. Low temperature synthesis of magnesium oxide and spinel powders by a sol-gel process
Magnesium oxide and magnesium aluminate (MgAl2O4) spinel (MAS) powders have been synthesized by a simple aqueous sol-gel process using citrate polymeric precursors derived from magnesium chloride, aluminium nitrate and citrate. The thermal decomposition of the precursors and subsequent formation of cubic MgO and MAS were investigated by X-ray diffraction (XR
Materials Research. Publicado em: 2010-09