Organic coatings coalescent

One of the problems encountered in the entrapment of activated charcoal in a polymer matrix is the blinding-off of the pores of the charcoal, thus inactivating it. Because the pores of the carbon are responsible for its ability to adsorb organics, any pores that are filled or coated with a polymer matrix reduce its effectiveness. Conventional treatments involve blending the carbon into an acrylic latex and then applying the slurry to a reticulated foam. Upon drying, a coalescence encapsulates the carbon. 

Fig. 4. SE images of organic polymer binders (a, b) in the primaiy form as dispersion and (c, d) coalesced in silicone resin coatings, a, b Typical particle shape of the primaiy latex particles after rapid diying in a vacuum, c, d Plaster/paint samples etched with 10% HNO3. c Plan view of a coalesced polymer binder of a silicone resin plaster and d cross-section of of a polymer film partly covering a clay mineral particle within a silicone resin emulsion paint.

Coalescence Coatings. In this type of coating, tiny particles of resin are encapsulated in a soap-like material and then dispersed in water, which acts as a diluent rather than as a tme solvent. This type of blend is known as an emulsion. When the water evaporates, the resin particles fuse (coalesce) to form a stable, cured coating film. These coatings, once cured, cannot be redissolved in water, although other organic solvents may dissolve them. These coatings consist of acrylic latex suspensions and epoxy emulsions. 

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