Emulsion polyether surfactants

A considerable amount of experimental work has been carried out on the so-called gel emulsions of water/nonionic surfactant/oil systems [9-14, 80, 106, 107]. These form in either the water-rich or oil-rich regions of the ternary phase diagrams, depending on the surfactant and system temperature. The latter parameter is important as a result of the property of nonionic surfactants known as the HLB temperature, or phase inversion temperature (PIT). Below the PIT, nonionic surfactants are water-soluble (hydrophilic form o/w emulsions) whereas above the PIT they are oil-soluble (hydrophobic form w/o emulsions). The systems studied were all of very high phase volume fraction, and were stabilised by nonionic polyether surfactants. 

The freeze/thaw (F/T) stability of a polymer emulsion serves as a macroscopic probe for investigating the properties of the average particle in a polymer emulsion. A review of the factors which contribute to this stability is included. A study of styrene-ethyl acrylate-methacrylic acid polymers shows the existence of a minimum in the plot of minimum weight percent acid required for F/T stability vs. the minimum film formation temperature (MFT) of the polymer. This is considered to be a function of both the amount of associated surfactant and the minimum acid content. Thus, both the type of surfactant and the copolymer ratio—i.e., MFT—play major roles. Chain transfer between radicals and polyether surfactant resulting in covalently bonded surfactant-polymer combinations is important in interpreting the results. 

The DLVO theory does not explain either the stability of water-in-oil emulsions or the stability of oil-in-water emulsions stabilized by adsorbed non-ionic surfactants and polymers where the electrical contributions are often of secondary importance. In these, steric and hydrational forces, which arise from the loss of entropy when adsorbed polymer layers or hydrated chains of non-ionic polyether surfactant intermingle on close approach of two similar droplets, are more important (Fig. 4B). In emulsions stabilized by polyether surfactants, these interactions assume importance at very close distances of approach and are influenced markedly by temperature and degree of hydration of the polyoxyethylene chains. With block copolymers of the ethylene oxide-propylene oxide... 

Chem. Descrip. Sodium alkylaryl polyether sulfate Uses Wetting agent, emulsifier, penetrant, high-foam detergent for household and industrial cleaners, emulsion polymerization surfactant for paints/coatings... 

Summary Water-in-silicone oil emulsions, stabilized by silicone-polyether surfactants, are marginally permeable to polar, but uncharged, molecules such as phenolphthalein and crystal violet. However, charged compounds, including these compounds in basic and acidic pH regimes respectively, and proteins transfer much less readily from the internal water phase to external bulk water. Transfer experiments were followed colorimetrically. These experiments shed light on the possible mechanisms by which proteins may be released from these emulsions in bioactive form simple breaking of the emulsion does not appear to be the mechanism of action. 

In the present paper, we examine the influence of structural variation within series of crown ether carboxylic acid and crown ether phosphonic acid monoalkyl ester carriers upon the selectivity and efficiency of alkali metal transport across three types of liquid organic membranes. Structural variations within the carriers include the polyether ring size, the lipophilic group attachment site and the basicity of ethereal oxygens. The three membrane types are bulk liquid membranes, liquid surfactant (emulsion) membranes and polymer-supported liquid membranes. 

Siloxane surfactants are crucial ingredients in personal care products they are the components of shampoos and conditioners that improve the softness and silkiness of hair, and are also used in shaving foams, toothpastes, antiper-spirants, cosmetics, hair-styling gels and bath oils. These applications follow from a combination of properties, e.g. low surface tension, water-solubility or dispersion in water to give emulsions, and low toxicity. Some of these properties contrast sharply with those required by polysilox-anes used in, for example, greases, sealants and rubbers. Siloxane surfactants contain a permethylated backbone which incorporates polar substituents. For example, polyether groups are hydrophilic and allow the polymers to be used in aqueous media, a prerequisite for use in shampoos and hair conditioners. 

Silicone oil in water (o/w) emulsions are more difficult to stabilize. To prepare such dispersions, nonionic PDMS-polyoxyalkylene copolymers with high degree of polyoxyalkylene substituents are generally used, in order to render the surfactant more hydrophilic. Thus, the resulting emulsions are sterically stabilized by the polyether chains... 

Surface-Active Materials. The active defoamer components are necessarily surface active materials, but this ancillary category covers the surfactants that are often incorporated in the formulation for other effects such as emulsification or to enhance dispersion. Emulsifiers are essential in the common oil-in-water emulsion systems, but they are also required where mixtures of active liquid components are used. For example, specialized oil-in-oil emulsifiers are needed in defoamers based on silicone/polyether mixtures, oil-in-water emulsifiers are incorporated in some defoamers even when the final product contains no water. This is to promote emulsification (self-emulsifiable) or dispersion into aqueous foaming systems. These additives increase the speed of foam decay by promoting rapid dispersion of the defoamer throughout the foaming media. Examples of emulsifying agents used in defoamer compositions are fatty acid esters and metallic soaps of fatty acids fatty alcohols and sulfonates, sulfates, and sulfosuccinates sorbi-tan esters ethoxylated products such as ethoxylated octyl or nonylphenols and silicone-polyether copolymers. 

Silicone-based materials are an important class of polymeric surfactants that are commonly used in the cosmetic industry. They consist of poly(dimethyl siloxane) (PDMS) that is modified by incorporation of specific groups for special applications. For example, dimethicone copolyol (used as emulsifier or dispersant) is typically a copolymer of PDMS and polyoxyalkylene ether. Aminofunctional silicones provide excellent hair-conditioning benefit. Polyether-modified silicones, including terpolymers containing an alkyl or polyglucoside moiety, are very effective emulsifiers for water-silicone emulsions. These silicone surfactants act as defoamers, depending on the amount and type of glycol modification. They are also used to reduce skin irritation. 

Miscellaneous silicone products. Most of the major silicone manufacturers sell over 100 different silicone products, and the applications of these cover a very wide range. Here there is space to mention only two more applications the first being the use of silicone oils and emulsions for the prevention of foam in numerous industrial processes, the other being the use of silicone-containing copolymers as surfactants in the manufacture of polyurethane foams from di-isocyanates, ethylene/propy-lene polyethers and a little water. Unless a suitable surface-active surfactant is added, polyurethane foams tend to collapse before the polymerization is complete. One of the best types of surfactant is a poly-siloxane to which polyethers are attached ... 

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