Antifoam agent

Antiferromagnetism Antifoam Antifoam agents Antifoaming agents... 

Antifoaming Agents. Foaming is a frequent problem in food manufacturing operations causing production inefficiencies. 

Phosphoms trichloride is also used in the manufacture of antifoam agents, catalysts, dyes and pigments, as well as pharmaceutical and quaternary compounds, and is commonly used as a chlorinating agent. Phosphoms trichloride is used to make phosphoms oxychloride, which is used in the manufacture of adsorbents for air filters, antifoam agents, dyes and pigments, mineral-processing materials, pharmaceuticals (qv), and solvents. These uses represented 32,000 t of PCl in 1988 and 30,000 t in 1994. 

Many of the unique properties of siUcone oils are associated with the surface effects of dimethylsiloxanes, eg, imparting water repeUency to fabrics, antifoaming agents, release liners for adhesive labels, and a variety of poHshes and waxes (343). Dimethylsilicone oils can spread onto many soHd and Hquid surfaces to form films of molecular dimensions (344,345). This phenomenon is greatly affected by even small changes in the chemical stmcture of siloxane in the siloxane polymer. Increasing the size of the alkyl substituent from methyl to ethyl dramatically reduces the film-forming abiUty of the polymer (346). The phenyl-substituted siUcones are spread onto water or soHd surfaces more slowly than PDMS (347). 

Quahty control testing of siUcones utilizes a combination of physical and chemical measurements to ensure satisfactory product performance and processibihty. Eor example, in addition to the usual physical properties of cured elastomers, the plasticity of heat-cured mbber and the extmsion rate of TVR elastomers under standard conditions are important to the customer. Where the siUcone appHcation involves surface activity, a use test is frequently the only rehable indicator of performance. Eor example, the performance of an antifoaming agent can be tested by measuring the foam reduction when the sihcone emulsion is added to an agitated standard detergent solution. The product data sheets and technical bulletins from commercial siUcone producers can be consulted for more information. 

Other U.S. regulatory clearances for sorbic acid allow its use as an antimicotic in the manufacture of food packaging materials (159), as a pesticide adjuvant when appHed to growing crops (160), and with methylceUulose and dimethylpolysiloxane as an antifoaming agent (161). 

Interfacial Phenomena These can significantly affect overall mass transfer. In fermentation reactors, small quantities of surface-active agents (especially antifoaming agents) can drastically reduce overall oxygen transfer (Aiba et al., op. cit., pp. 153, 154), and in aerobic... 

Other additives. It is often necessary to add an antifoaming agent, such as silicones or mineral oils. 

In an offshore oil production platform, a major accident occurred partly because pump seals failed and therefore an antifoaming agent was not delivered to a crude oil separator. The fact that the pump seals were defective should have been picked up during routine inspections, but the inspections were neglected because of production pressures. The failure to carry out the inspections was a latent error. 

Entschaumer, m. skinuner, scummer, foam remover antifoam agent, entscheiden, v.t. decide. — entscheidendi p.a. decisive flnal. 

---