Influence of pH on the stability of alumina suspensions electrosterically stabilized

Quimica nova

Rodrigues Neto, João Batista¹  Longo, Elson²  Sales, Luciano Leal de Morais³  Santos, Iêda Maria Garcia dos³  Souza, Antonio Gouveia de³  Soledade, Luis Edmundo Bastos³  Paskocimas, Carlos Alberto⁴ 

[1] Serviço Nacional de Aprendizagem Industrial Tijucas/SC, Tijucas, Brasil;Universidade Estadual Paulista, Araraquara, Brasil;Universidade Federal da Paraíba, João Pessoa, Brasil;Universidade Federal do Rio Grande do Norte, Natal, Brasil

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 deflocculantwas optimized and rheologic properties were determined at four different pHvalues. Sedimentation was also evaluated. For suspensions with pH 4, an electrostaticmechanism of stabilization was observed, probably due to a flat adsorption ofPMMA- on the alumina surface, leading to a small efficiency in relationto steric stabilization. For a suspension with pH 12, the steric mechanism ofstabilization prevails. Suspensions with pH 7 and 9 present a higher flocculationdegree. In relation to particle size, A-1000 samples present a smaller particlesize, leading to a smaller interparticle distance (IPS), making stabilizationmore difficult.

【 授权许可】

CC BY