Emulsifying Effect

Emulsions are disperse systems of one or more immiscible liquids. They are stabilized by emulsifiers - compounds which form interface films and thus prevent the disperse phases from flowing together (cf. 8.15). Due to their amphipathic nature, proteins can stabilize o/w emulsions such as milk (cf. 10.1.2.3). This property is made use of on a large scale in the production of food preparations. 

The solubility and emulsifying capacity of some proteins can be improved by limited enzymatic hydrolysis. 

Guanidination can be accomplished by using 0-methylisourea as a reactant, a-Amino groups react at a much slower rate than e-amino groups  

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With respect to good adhesion, reduced interfacial tension, fine distribution of TLCP phase, and the use of a compatibilizer can be very effective for this purpose. Remarkably improved mechanical properties (good impact properties as well as tensile properties) can be obtained with optimum amounts of the compatibilizer. Excess amounts of the compatibilizer causes the emulsifying effect to coalesce the dispersed TLCP... 

The theory of Leibler holds for mainly compatible systems. Leibler developed a mean field formalism to study the interfacial properties of two polymers, A and B with an A-B copolymer. An expression for interfacial tension reduction was developed by Noolandi and Hong [ 18] based on thermodynamics to explain the emulsifying effect of the A-b-B in immiscible A-B blends (A-A-b-B-B). [18,19]. The expression for interfacial tension reduction Ar) in a binary lend upon the addition of divalent copolymer is given by ... 

Emulsifier Effect on Volatilization of Pesticides from Water... 

Riess G, Periard J, Banderet A Emulsifying Effect of Block Graft Copolymers - Oil in Oil Emulsions In G. E. Molau (ed) Colloidal and Morphological Behaviour of Block and Graft Copolymers (Proceedings of an American Chemical Society Symposium held at Chicago, Illinois, Sep. 13, 1970)... 

We will discuss several problems related to the isolation process based on our experimental results and present effective isolation methods, especially noting the emulsifying effect of graft copolymers on the isolation. For illustrative purposes attention will be confined to the graft copolymers with one branch, but similar considerations may apply to those with many branches and block copolymers. 

Leibler L (1988) Emulsifying effects of block copolymers in incompatible polymer blends. Makromol Chem, Marcomol Symp 16 1-17... 

Emulsifiers are added to toffees to help disperse the fat (see also Chapter 4), although it is perfectly possible to make toffees that do not contain added emulsifiers if sufficient skim milk solids are present. The emulsifying effect of a considerable quantity of skim milk solids can be replaced by a very small quantity of an emulsifier, e.g. lecithin or distilled monoglycerides, and the price of skim milk in the EU makes this an attractive proposition. Curiously, fat that is too well dispersed can cause problems. If some fat coats the surface of the piece then the toffee will cut easily as the fat lubricates the cutting knife if there is no surface fat then the toffee can stick to the knife. One solution to this is to have a cutting knife coated with PTFE. The PTFE has a very low energy surface that the toffee will not stick to. 

Concentrated detergent lonic/Nonionic detergent emulsifier Effective wetting agent for all fibers Easily rinsed from goods Stable to wide ranges of pH... 

The eggs and egg products, thanks to their texture-improving properties, emulsifying effect, and foaming ability, are multifunctional components used in food technology in liquid or dried form. 

Periard J, Banderet A, Riess G. Emulsifying effect of block and graft copolymers—oil in oil emulsions. Polym Lett 1970 8 109—114. 

Davies JT. A quantitative kinetic theory of emulsion type. I. Physical chemistry of the emulsifying effect. Proc 2nd Int Cong Surf Activity 1957 1 417— 421. 

Oil-in-Oil Emulsions. We demonstrated previously that block and graft copolymers act as oil-in-oil emulsifiers for the corresponding incompatible homopolymers, e.g., PS and PI (I, 2, 3). To prove that this emulsifying effect of AB block and graft copolymers is general, we studied the simpler case of two nonmiscible liquids a and b which do not have the inconvenient high viscosity typical of polymeric systems. Furthermore, a is a good solvent for... 

The emulsifying effect of a copolymer can be characterized by determining the type of emulsion (DMF in hexane or hexane in DMF), its stability, its viscosity, and the particle size of the dispersed phase. These characteristics of oil-in-oil emulsions obtained with PS-PI block copolymers were studied as functions of solvent volume ratio, molecular weight, composition, and structure of the copolymer (5). Although Bancroft s rule was established for conventional oil-water emulsions, it appears to apply also to oil-in-oil emulsions—the continuous phase of the emulsion is preferentially formed by the solvent having the best solubility for the emulsifier (6, 7). Thus, block or graft copolymers can be prepared giving hexane/DMF, DMF/hexane, or both types of emulsions. 

Emulsifying Effect of Copolymers in the Solid State. The next step was to ascertain if the findings for two nonmiscible liquids are applicable to two incompatible polymers such as PS and PI, and if a block copolymer also functions as an emulsifier. 

The film preparation technique has been described elsewhere (3). It should be noted that films are observed directly and by phase contrast microscopy. Thus, we can compare the emulsifying effect of different styrene-isoprene copolymers (random, block, and graft copolymers) of the same overall composition (40 wt % PS, 60 wt % PI) and practically the same molecular weight (Mn — 50,000) in a given PS-PI blend, where Mn of PS is 45,000 and Mn of PI is 25,000. The appearance of the films obtained with different blend compositions is depicted in Figure 1. Hazy or opaque areas are striped. From Figure 1, it appears that random copolymers always cause hazy films which means... 

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