Influência do pH sobre a estabilidade de suspensões de alumina estabilizadas eletroestericamente

Química Nova

Luciano Leal De Morais Sales²  Antonio Gouveia De Souza²  Luis Edmundo Bastos Soledade²  Iêda Maria Garcia Dos Santos²  João Batista Rodrigues Neto¹  Elson Longo¹  Carlos Alberto Paskocimas¹ 

[1] ,Universidade Federal da Paraíba Departamento de Química João Pessoa PB ,Brasil

关键词: pH;    polymethylmethacrylate;    alumina;   

DOI  :  10.1590/S0100-40422007000100016

来源: SciELO

【 摘 要 】

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.

【 授权许可】

CC BY-NC   
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