Surfactants antifoaming agents

Approximately 70,000 tons of silicone polymers are produced each year In the United States. Silicones are used as greases, caulking, gaskets, biomedical devices, cosmetics, surfactants, antifoaming agents, hydraulic fluids, and water repellents. 

Others sweeteners, flavors, colors, surfactants, antifoaming agents (polydimethylsiloxane). 

Yagi H, Yoshida F. (1974) Oxygen absorption in fermenters—effects of surfactants, antifoaming agents and sterilized cells. J. Ferment. Technol., 52 905-916. 

Chem. Desaip. Linear polymer of all oxypropylene groups Uses Component of adhesives used In articles Intended for food contact component of defoaming agents used In mfg. of cellophane and coatings for paper and paperboard component of surf, lubricants in mfg. of metallic articles in contact with food mbber lubricant coaling for hydraulic brake parts and similar equip. reactive Inlennediale in preparation of resins, plasticizers, modifiers, and surfactants antifoam agent... 

Foam Control. Fermentations tend to froth because metabolites have surfactant properties. Prevention commonly is by addition of antifoam agents such as oils, heavy alcohols, fatty acids, or silicones. High-speed rotating impellers destroy bubbles by direct impact and by throwing them against the wall of the vessel. 

On the other hand, some substances, even in minute concentrations, promote coalescence. Some of the non-ionic surfactants often used as antifoaming agents are so effective that a concentration of 3 ppm is sufficient to halve the kLaL of pure water (Zlokarnik, 1979). Clearly the use of surfactants for foam prevention should be avoided whenever possible, and an efficient mechanical foam breaker should be used (Zlokarnik, 1986). 

Lubricants such as magnesium stearate are not used as their aqueous insolubility leads to cloudy solutions and extended disintegration times. Spray-dried leucine and PEG are water-soluble alternatives [15,16]. Both artificial and natural sweeteners are used and an additional water-soluble flavoring agent may also be required. If a surfactant is added to enhance wetting and dissolution, the addition of an antifoaming agent may also be considered [17]. 

HERCULES 831 defoamer is a quick-dispersing, hydrocarbon oil-based antifoaming agent designed for use where immediate foam-control action is wanted. It is particularly suitable where addition adjacent to the foam-control point is required. Its efficiency is not adversely affected by temperature or pH, and it is effective in the presence of many surfactants. 

Use Surfactants, metal cutting oils, printing inks, textile finishing, antifoam agent, plasticizer. 

When undesirable foaming of a solution cannot be reduced sufficiently by replacing the surfactant with a lower foaming one, or when the foam is caused partially or entirely by nonsurfactant components of the solution, then antifoaming agents are used to reduce the foam. Antifoaming agents act in various ways ... 

---