Aqueous cleaning agents types

Table 3.1a Types of Semi-Aqueous Cleaning Agents (SAs) ...

In an aqueous latex that has been cleaned to remove various materials such as suifece active agents one is dealing in many cases with a dispersion of charged spherical particles. Frequently, the distribution of particle sizes is veiy narrow and the term monodisperse is used to describe latices of this type. In an attempt to obtain a concise overview of the properties of aqueous latices in electrolyte solutions some of the essential features are summarized schematically in Fig. 4. 

Kim et al. [208] synthesized perovskite-type Pb(Mgi/3Nb2/3)03 powders by an emulsion method with (a) an aqueous solution of lead nitrate, magnesium nitrate hexahydrate and niobium oxalate as the water phase, (b) Span 80 as the surfactant, (c) paraffin oil as an emulsifying agent and (d) kerosene as the oil phase. The emulsion of short stability, prepared by high speed mixing, was added drop by drop into petroleum heated at 170 C. The product particles were washed in toluene and cleaned at 150"C. Careful calcination yielded dominantly a pyrochlore phase at 600 C, but only the desired perovskite-type niobate at 800 C. 

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