Micro- and nanocomposites of Keggin heteropolymetalates in cellulose esters |
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| Authors: | Francílio de C Oliveira José Schneider Abner Siervo Richard Landers Ana M G Plepis Jean-Jacques Pireaux Ubirajara Pereira Rodrigues-Filho |
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| Institution: | 1. Universidade de São Paulo, Instituto de Química de São Carlos, 13564-970, PO Box 780, São Carlos, SP, Brazil;2. Universidade de São Paulo, Instituto de Física de São Carlos, 13564-970, São Carlos, SP, Brazil;3. Universidade Estadual de Campinas, Instituto de Física Gleb Wattaghin, Campinas, SP, Brazil;4. Laboratoire Interdisciplinaire des Spectroscopies Electroniques, Facultes Universitaires Notre-Dame de la Paix, Namur B-5000, Belgium |
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| Abstract: | Composites of Keggin heteropolymetalates have been prepared and characterized by SEM, XPS, 31P-magic angle spinning/nuclear magnetic resonance and differential scanning calorimetry. The phosphotungstic acid and phosphomolybdic acid form nanocomposites where the oxocluster structure is preserved and is highly dispersed over the material, probably inserted between the polymeric chains. Phosphovanadotungstic clusters suffer partial decomposition during composite formation, resulting in a biphasic microcomposite. The decomposition product, phosphotungstic acid presents surface segregation as shown by comparison of XPS and nuclear magnetic resonance results. Copyright © 2002 John Wiley & Sons, Ltd. |
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| Keywords: | cellulose acetate butyrate Keggin heteropolymetalates nanocomposites XPS |
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