Fatty emulsification

Inversion ofMon cjueous Polymers. Many polymers such as polyurethanes, polyesters, polypropylene, epoxy resins (qv), and siHcones that cannot be made via emulsion polymerization are converted into latices. Such polymers are dissolved in solvent and inverted via emulsification, foUowed by solvent stripping (80). SoHd polymers are milled with long-chain fatty acids and diluted in weak alkaH solutions until dispersion occurs (81). Such latices usually have lower polymer concentrations after the solvent has been removed. For commercial uses the latex soHds are increased by techniques such as creaming. 

The mechanisms by which an alkaline cleaner removes the soil are saponification, emulsification, and dispersion. These mechanisms can operate independently or in combination. Saponification occurs when alkaline salts react with fatty components of the soil, forming a soluble soap compound. 

Defoamers (qv) are available in several forms, composed of many different materials. Historically, paste and soHd defoamers were used extensively. Composed of fatty acids, fatty amides, fatty alcohols, emulsifiers (and mineral oil [8012-95-1] in the high soflds paste emulsions), these defoamers required emulsification (brick) or dilution (paste) before use. Liquid defoamers have become the preferred form, insofar as concern about handling and ovemse have been overcome. 

Emulsions. The fatty acid soaps of alkanolamines ate excellent emulsification agents for use in such products as floor poHshes, cosmetics, and functional fluids such as hydrauhc and metalworking fluids. For example, improved hardwater stabiUty of a hydrauhc fluid emulsion is obtained using AMP in the formulation (12). 

At room temperature, ca 60 wt % ethylene oxide is needed to solubilize the fatty acids. Surface activity of the ethoxylates is moderate and less than that of alcohol or alkylphenol ethoxylates (84). The ethoxylates are low foamers, a useful property in certain appHcations. Emulsification is the most important function. Its importance is reflected in the wide range of lipophilic solubiHties available in the commercial products. Like all organic esters, fatty acid ethoxylates are susceptible to acid and alkaline hydrolysis. 

Surfactant Fatty acid soaps Emulsification of product... 

Inverse emulsification A solution of the polymer within a volatile, water-immiscible organic solvent (or mixture of solvents) or a polymer melt is compounded with a long-chain fatty acid (e.g., oleic acid) using conventional rubbermixing equipment and mixed slowly with a dilute aqueous phase to give a W/O emulsion,... 

The long-chain, fatty acid esters of sucrose are non-ionic, nontoxic, and biodegradable, and compare well in overall performance with other surface-active compounds in detergency, emulsification, and... 

Soap. The reaction product of a fatty acid ester and a metal hydroxide, usually sodium hydroxide. Soap lowers the surface tension of water, permitting emulsification of soil-bearing fats if the soap is used for washing, of monomers in solution if the soap is used for emulsification in a polymerization process. 6 e saponification. 

Although all the sodium salts are, as is indicated by the lowering of the surface tension, adsorbed at the interface the concentrations necessary to efiPect emulsification are so great for the salts of the short chain fatty acids that precipitation by the sodium ions results before the protective film can be built up. The first signs of emulsification are noted in the case of sodium caprate and sodium nonylate coinciding with the appearance of colloidal properties on solution. 

Alkaline cleaners are available which allow the separation of excess oily soil from the cleaner. These formulations involve the use of surfactants that are good detergents but poor emulsifiers. Agitation of the bath during the work shift causes a temporary emulsification, which keeps the soil in suspension. After a prolonged period of inactivity (usually overnight), the oily soils float to the surface where they are skimmed off. This method is quite effective with mineral oil-type soils but is less so with fatty oils. 

Extraction of nonpolar compounds using equal volumes of sample and the Folsch mixture (2 1, chloroform/MeOH) gives a very broad polarity cut. Everything from steroids to triglycerides is pulled down into the bottom chloroform-rich layer. Extraction with methylene chloride from a sample acidified with sulfuric acid is more specific, pulling in steroids, fat-soluble vitamins, and free fatty acids. The triglyceride fraction can be extracted using i-PrOH/ hexane (1 9) with little emulsification. 

Bile salts are substances derived from sterols, which make up a substantial part of the solid matter in bile and which play a central role in lipid absorption, by virtue of their surface-active properties. The structure and properties of these salts have been reviewed by Haslewood (305) and Heaton (316). Bile salts essentially have molecules of detergent type hydrocarbon, with a fat-dissolving part and a polar, water-attracting part. The fat-dissolving part consists of the bulk of the steroid nucleus. The hydroxyl groups are so distributed that hydration can readily take place the remainder of the molecule will dissolve the fatty phase. Emulsification of fat/water complexes can thus occur easily. The terms bile acid and bile salt are used somewhat interchangeably in the literature. 

Self-emulsifiable oils Fatty alcohol ethoxylates Polyglycol esters Emulsification... 

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