"Estabilização de suspensões aquosas de alumina pela adição de taninos e quitosana quaternizada" / Stabilization of aqueous alumina suspensions by addition of tannin and quaternized chitosan

AUTOR(ES)

Bianca Machado Cerrutti

DATA DE PUBLICAÇÃO

2005

RESUMO

The ceramic industry provides products for several areas, and new processing techniques became necessary to meet the quality requirements. The objective is to produce more homogeneous green microstructures (bodies before burning), with lower number of micro-defects. Such materials can be produced from aqueous suspensions of aluminum oxide (Al2O3), known as alumina. These suspensions have a large number of solid particles, and dispersion of particles may be assisted by the addition of other species, increasing stability. These species can be polyelectrolytes (polymers with charges) that interact with the surface of alumina particles, hindering the approach of other particles. In this work, vegetal macromolecules such as tannins and chitosan, polysaccharides found in exoskeleton of crustaceans, are used as stabilizing (stabilization) agents of the suspension. Evaluation of the suspension stability, due to addition of these macromolecules, is performed through measurements of viscosity, zeta potential, particle diameter, pore size and sedimentation tests. The overall aim is the attainment of less viscous suspensions with smaller particles and greater fluidity, i.e. more homogeneous suspensions that lead to better-quality products. Amongst the stabilizing agents used, the tannins presented the better performance, contributing for a reduction in viscosity and particle size, in addition to a better wrapping up in the sedimentation tests. Although the quaternized chitosan has also contributed for a decrease in viscosity and particle size, it presented inferior performance, in comparison to that of tannins. These results were nevertheless promising, and a further study with chitosan is recommended, in which other conditions are employed.

ASSUNTO(S)

aeta potential estabilização macromoléculas naturais suspensions potencia zeta stabilization suspensões chitosan particle size diâmetro partículas tannin

Documentos Relacionados

• Carboximetilquitosanas: preparação, caracterização e aplicação como agentes de estabilização de suspensões aquosas de alumina
• Biomacromoléculas carboximetiladas: atuação como agentes de estabilização de suspensões aquosas de alumina
• Artigo revisão: estabilização de suspensões aquosas contendo grafite
• Nanoparticle assisted coagulation of aqueous alumina suspensions
• Processamento viscoplástico e conformação cerâmica por rolos a frio a partir de suspensões concentradas de alumina.