Spray drying, solid electrolytes

The final product of an emulsion polymerization is referred to as latex. Emulsion polymerization products can in some instances be employed directly without further separations but with appropriate blending operations. Such applications involve coatings, finishes, floor polishes, and paints. Solid polymer can be recovered from the latex by various techniques such as spray drying, coagulation by adding an acid, usually sulfuric acid, or by adding electrolyte salts. 

Bulk polymerization procedures are known. Suspension polymerization in aqueous media loaded with high concentrations of electrolyte are possible. Work has also been carried out on solid-state polymerizations. However, the most important methods of polymerization are solution processes, particularly using water as the solvent. If the dry polymer is desired, it may be extracted with a suitable solvent, precipitated, or isolated by solvent evaporation. Freeze drying or spray drying have also been used. 

The results of development work on processes indicate that the two main methods of preventing the duplex microstructure from forming appear to be fast-firing, or increasing the amount of / "-alumina at low temperatures. Based on these results, Duncan et al. [21] and Zyl et al. [22] have described production processes starting from aluminum oxyhydroxides or aluminum hydroxides as precursors for the synthesis of the solid electrolyte "-alumina. Duncan et al. described an alumina precursor which substitutes in part or wholly for a-alumina in an established slurry solution spray-drying process. As a precursor, hydrothermal boehmite, Cera hydrate, has been used. A calcination step is important at the begirming of the process. Boehmite was used both in the as-received condition and after calcination. The effect of the calcination temperature on the fired properties of /S"-alumina can be seen in Table 21.5. 

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