Frothing, foamed plastics

Foam Products. Latices are made into foams for use in cushioning appHcations. The latices are frothed with air and then chemically coagulated for thick appHcations, or heated to induce coagulation for thinner appHcations. The latter method allows for infinite pot life during production (see Foamed plastics). 

Foam Production This is important in froth-flotation separations in the manufac ture of cellular elastomers, plastics, and glass and in certain special apphcations (e.g., food products, fire extinguishers). Unwanted foam can occur in process columns, in agitated vessels, and in reactors in which a gaseous product is formed it must be avoided, destroyed, or controlled. Berkman and Egloff (Emulsions and Foams, Reinhold, New York, 1941, pp. 112-152) have mentioned that foam is produced only in systems possessing the proper combination of interfacial tension, viscosity, volatihty, and concentration of solute or suspended solids. From the standpoint of gas comminution, foam production requires the creation of small biibbles in a hquid capable of sustaining foam. 

Other new materials are frothed or lightened syntactic plastics, which can be either isotropic 101 n0,111 132 —134.) or anisotropic 116). They have also been called integral (structural) syntactic foams and the smallest density obtained is 67 kg/m3 67). 

MAA (108-31-6) Combustible solid (flash point 215°F/102°C). Dust cloud forms an explosive mixture with air. Dissolves in water, forming maleic acid with release of energy. Violent reaction with strong oxidizers, strong alkalis. Contact with amines or alkali metals lithium, sodium, potassium, rubidium, cesium, and francium (even in low concentrations of 200 ppm) can decompose rapidly and may cause polymerization, especially if temperature is >150°F/66°C. Incompatible with pyridine. Attacks metals in the presence of moisture. Attacks some plastics, rubber, and coatings. In firefighting, water stream or foam may cause frothing. 

---