[en] BaTiO3 gels were prepared by hydrolysis and polycondensation reactions between titanium isopropoxide and barium hydroxide in presence of methoxyethanol, methanol and water. The rheology of the sol-gel transition was studied with a rheometer allowing low amplitude sinusoidal oscillations. Experimental data show a continuous increase in the complex viscosity along with time, showing the progressive character of the transition. The influence of synthesis operating variables was studied. The gelation time, which definition is based on viscoelastic measurements, increases exponentially when the water content is increased, when the dilution due to the methoxyethanol is reduced or when the temperature is lowered. Different growth models were used for the characterization of the particles in the solution. These models suggest that the polymerisation first produces spherical particles (mass fractals) and that these spherical particles then agglomerate to form a linear network.
Disciplines :
Materials science & engineering Chemical engineering
Author, co-author :
Brasseur, Alain; Université de Liège - ULiège > Département de Chimie appliquée > Génie chimique - Chimie physique appliquée
Michaux, Bernard; Université de Liège - ULiège > Département de Chimie appliquée > Génie chimique - Chimie physique appliquée
Pirard, René ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Chimie physique appliquée
Van Cantfort, Olivier; Université de Liège - ULiège > Département de Chimie appliquée > Génie chimique - Chimie physique appliquée
Pirard, Jean-Paul ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Chimie physique appliquée
Lecloux, A. J.
Language :
English
Title :
Rheological characterization of BaTiO3 sol-gel transition
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