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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Novel Insights on Swelling and Dehydration of Laponite

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Autor(es):
Valencia, G. A. [1, 2] ; Djabourov, M. [2] ; Carn, F. [3] ; Sobral, P. J. A. [1]
Número total de Autores: 4
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Fac Anim Sci & Food Engn, Dept Food Engn, Pirassununga, SP - Brazil
[2] PSL Res Univ, ESPCI Paris, Lab Phys Therm, 10 Rue Vauquelin, F-75231 Paris 5 - France
[3] Univ Parsis Diderot Paris 7, Lab Matiere & Syst Complexes, UMR 7057, Case Courrier 7056, F-75205 Paris 13 - France
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: COLLOID AND INTERFACE SCIENCE COMMUNICATIONS; v. 23, p. 1-5, MAR 2018.
Citações Web of Science: 2
Resumo

This paper investigates water sorption and dehydration of model synthetic clay (Laponite) and highlights the large differences with natural Na-smectite clays. Measurements were done by combining for the first time thermogravimetric analysis and X-ray diffraction methods on Laponite powders stored in atmospheres with controlled relative humidity. Laponite exhibits a very good reproducibility of the sorption diagram and appears as the most hygroscopic among Na-smectites. The interlayer distance increases from 11 to 20 angstrom when the ratio r = n(H2O)/n(Na) increases from 2 to 22, in agreement with recent numerical simulations. The desorption process, in this range of r, in isothermal conditions follows a first order kinetics with two regimes around r{*} = 7 which is close to the coordination number of Na+ ions in concentrated NaCl solution. Activation energies and frequency factors are derived for the two regimes of desorption and discussed in relation with stability of the cationic complex. (AU)

Processo FAPESP: 12/24047-3 - Propriedades físicas de filmes a base de biopolímeros reforçados com laponita
Beneficiário:Germán Ayala Valencia
Modalidade de apoio: Bolsas no Brasil - Doutorado
Processo FAPESP: 13/07914-8 - FoRC - Centro de Pesquisa em Alimentos
Beneficiário:Bernadette Dora Gombossy de Melo Franco
Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs