Influência do pH sobre a estabilidade de suspensões de alumina estabilizadas eletroestericamente
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Data
2007-02-01
Autores
Sales, Luciano Leal de Morais
Souza, Antonio Gouveia de
Soledade, Luis Edmundo Bastos
Santos, Iêda Maria Garcia dos
Rodrigues Neto, João Batista
Longo, Elson [UNESP]
Paskocimas, Carlos Alberto
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Química
Resumo
In this work, aqueous suspensions of aluminas with different particle sizes were evaluated. The effect of pH on the electrosteric stabilization using PMAA-NH4 (ammonium polymethacrylate) as deflocculant was studied. The amount of deflocculant was optimized and rheologic properties were determined at four different pH values. Sedimentation was also evaluated. For suspensions with pH 4, an electrostatic mechanism of stabilization was observed, probably due to a flat adsorption of PMMA- on the alumina surface, leading to a small efficiency in relation to steric stabilization. For a suspension with pH 12, the steric mechanism of stabilization prevails. Suspensions with pH 7 and 9 present a higher flocculation degree. In relation to particle size, A-1000 samples present a smaller particle size, leading to a smaller interparticle distance (IPS), making stabilization more difficult.
Descrição
Palavras-chave
pH, polymethylmethacrylate, alumina
Como citar
Química Nova. Sociedade Brasileira de Química, v. 30, n. 1, p. 70-74, 2007.