Ceramic suspensions surfactants

L. Bergstrom, Rheology of concentrated suspensions, in R.J. Pugh and L. Bergstrom (Eds.), Surface and Colloid Chemistry in Advanced Ceramic Processing. Surfactant Science Ser., 51, Dekker, New York, 1994, p. 200. 

Nonionic surfactants and both natural and synthetic polymers (which are collectively referred to as polymeric surfactants), when used to stabilise soHd/hquid (suspensions) andliquid/liquid (emulsions) disperse systems, play important roles in many industrial applications including paints, cosmetics, agrochemicals, and ceramics. Nonionic surfactants and polymers are particularly important for the preparation of concentrated dispersions - that is, with a high volume fraction

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Adsorption of surfactants has developed into a domain on Its own. So far we have only introduced the non-ionic part (sec. 2.7d). Abundant applications are found in detergency, flotation, enhanced oil recovery, drug administration and other pharmaceutical purposes, paints, cosmetics, ceramic materials and the stabilization of suspensions in general. 

Several classes of formulations of disperse systems are encountered in the chemical industry, including suspensions, emulsions, suspoemulsions (mixtures of suspensions and emulsions), nanoemulsions, multiple emulsions, microemulsions, latexes, pigment formulations, and ceramics. For the rational preparation of these multiphase systems it is necessary to understand the interaction forces that occur between the particles or droplets. Control of the long-term physical stability of these formulations requires the application of various surfactants and dispersants. It is also necessary to assess and predict the stability of these systems, and this requires the application of various physical techniques. 

Zeolite BEA(75) coatings can be deposited on a ceramic cordierite (2AI2O3 5Si02 2MgO) monolithic substrate. The coating is performed with a suspension of zeolite, with silica as the binder, and a surfactant in water. The mixture is well stirred the cordierite monolith is dipped into the mixture and dried at 200°C, and finally is calcined at 400°C for 4 h. ... 

Modify Pt/ceria catalyst suspensions with surfactants and binders, and washcoat catalysts onto ceramic honeycomb monoliths. 

The use of surfactants (ionic, nonionic and zwitterionic) and polymers to control the stability behavior of suspensions is of considerable technological importance. Surfactants and polymers are used in die formulation of dyestuffs, paints, paper coatings, agrochemicals, pharmaceuticals, ceramics, printing inks, etc. They are particularly robust form of stabilization which is useful at high disperse volume fractions and high electrolyte concentrations, as well as under extreme conditions of high temperature, pressure, and flow. In particular, surfactants and polymers are essential for the stabilization of suspensions in nonaqueous media, where electrostatic stabilization is less successful. 

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