Foam control surfactants

Chem. Descrip. Polyalkylene glycol ether Uses Defoamer for soap and detergent foam control surfactant Witconol 1206 [Chemtura]... 

Wyandotte. Foam Control with Wyandotte Surfactants. Technical Publication. Wyandotte Chemical Corporation (now BASF AG), USA 1970. 

The unique surface characteristics of polysiloxanes mean that they are extensively used as surfactants. Silicone surfactants have been thoroughly studied and described in numerous articles. For an extensive, in-depth discussion of this subject, a recent chapter by Hill,476 and his introductory chapter in the monograph he later edited,477 are excellent references. In the latter monograph, many aspects of silicone surfactants are described in 12 chapters. In the introduction, Hill discusses the chemistry of silicone surfactants, surface activity, aggregation behavior of silicone surfactants in various media, and their key applications in polyurethane foam manufacture, in textile and fiber industry, in personal care, and in paint and coating industries. All this information (with 200 cited references) provides a broad background for the discussion of more specific issues covered in other chapters. Thus, surfactants based on silicone polyether co-polymers are surveyed.478 Novel siloxane surfactant structures,479 surface activity and aggregation phenomena,480 silicone surfactants application in the formation of polyurethane foam,481 foam control and... 

Although silicone oils by themselves or hydrophobic particles (e.g., specially treated silica) are effective antifoams, combinations of silicone oils with hydrophobic silica particles are most effective and commonly used. The mechanism of film destruction has been studied with the use of surface and interfacial tensions, measurements, contact angles, oil-spreading rates, and globule-entering characteristics for PDMS-based antifoams in a variety of surfactant solutions.490 A very recent study of the effect of surfactant composition and structure on foam-control performance has been reported.380 The science and technology of silicone antifoams have recently been reviewed.491... 

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. 

Composition vs. performance. With this product group, little work has been done in this area. As already seen, the a-sulpho fatty acids show poor solubility, even at higher temperatures and they do not foam like a usual anionic surfactant. It is well known that many sulphonates do not foam well in the presence of soaps and it may be that, since these surfactants contain both the sulphonate and soap function, they effectively have internal foam control. 

This analysis, though qualitative, indicates that foam films cannot form for two main reasons lack of sufficient amount of a surfactant and slow diffusion of the latter towards to surface of the forming film. The problem of the kinetics of foam film formation and, in particular, the initial thickness of its formation awaits its quantitative explanation. It should be noted that formation of films with small initial thickness can be used to control surfactant purity as well as to develop a technique to control water purity. 

The most widely used in foam control are special materials called antifoams. They could be fats, oils, waxes, fatty alcohols and acids, ethers, organic compounds containing nitrogen and sulphur (alkylamines and amides, sulphides, thioethers, etc.), phosphorus organic compounds (in particular, tributylphosphate), silicon-organic compounds (silicon oils) and some non-ionic surfactants [e.g. 4,5]. 

The surfactant systems used for mobility control in miscible flooding do not form a surfactant rich third phase, and lack its buffering action against surfactant adsorption. Furthermore, for obvious economic reasons, it is desirable to keep the surfactant concentration as low as possible, which increases the sensitivity of the dispersion stability to surfactant loss. Hence, surfactant adsorption is necessarily an even greater concern in the use of foams, emulsions, and dispersions for mobility control in miscible-flood EOR. The importance of surfactant adsorption in surfactant-based mobility control is widely recognized by researchers. A decision tree has even been published for selection of a mobility-control surfactant based on adsorption characteristics (12). 

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. 

Poly(propylene oxide) is typically obtained by base catalyzed anionic polymerization of propylene oxide [12]. Both stereospecific and atactic forms are known. The polymer is used as a soft polyether unit in polyurethane elastomers and foams in polymer electrolytes as surfactants (lubricants, dispersants, antistatic agents, foam control agents) in printing inks, as solubilizers in hydraulic fluids, coolant compositions in various medical applications (protective bandages, drug delivery systems, organ preservation, dental compositions), etc. 

Figure 13.5. Micrographs of rigid polyurethane foams, left - surfactant/silica foam, right - control. Magnification 30x. [Adapted, by permission, from Okoroafor M O, Wang A, Bhattacharjee D, Cikut L, Haworth G J, Polyurethanes 95. Conference Proceedings, Chicago, 11., 26th-29th Sept.1995, 303-9.]...

U.S. 4306987 (1981) [122] Kaneko (BASF Wyandotte) Block polyoxyalkylene nonionic surfactant Effective foam control spot-free wash items effective against encrusted protein soils... 

Over few last decades, applied problems have arisen which are related to the behavior of foams in porous media. It turns out that aqueous surfactant-stabilized foams can drastically reduce the gas mobility in porous media [334], This fact is of great applied significance in petroleum and gas industry. In [106, 189, 233], mechanisms of foam control of gas migration through porous media are presented. 

This section has demonstrated that some commercially available surfactants are soluble in brines of extreme salinity and hardness and also form effective mobility control foams under these conditions. The remainder of this chapter is devoted to the development of a better understanding of the adsorption properties of foam-forming surfactants, mainly those for high-salinity conditions. It is hoped that this discussion will contribute to the development of a systematic approach for selecting or formulating surfactants with minimal adsorption levels. 

Marlox . [HOls Am. Hals AG] PPG ethoxylated ethers surfactants, detergents, andstats, foam controllers, wetting agents fot botde cleaning, textile auxili es, industrial cleaneis. 

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