Influence of pH on the stability of alumina suspensions electrosterically stabilized

Química Nova

Paskocimas, Carlos Alberto¹  Serviço Nacional de Aprendizagem Industrial Tijucas/SC, Tijucas, Brasil¹  Universidade Federal do Rio Grande do Norte, Natal, Brasil¹  Universidade Federal da Paraíba, João Pessoa, Brasil¹  Rodrigues Neto, João Batista¹  Sales, Luciano Leal de Morais¹  Universidade Estadual Paulista, Araraquara, Brasil¹  Longo, Elson¹  Santos, Iêda Maria Garcia dos¹  Souza, Antonio Gouveia de¹  Soledade, Luis Edmundo Bastos¹ 

关键词: pH;    polymethylmethacrylate;    alumina.;   

DOI  :  10.1590/S0100-40422007000100016

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 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】

Unknown