Emulsions properties

Reynolds number based on emulsion properties prior to polymerization, dimensionless... 

Although NMRI is a very well-suited experimental technique for quantifying emulsion properties such as velocity profiles, droplet concentration distributions and microstructural information, several alternative techniques can provide similar or complementary information to that obtained by NMRI. Two such techniques, ultrasonic spectroscopy and diffusing wave spectroscopy, can be employed in the characterization of concentrated emulsions in situ and without dilution [45],... 

Studies of flow-induced coalescence are possible with the methods described here. Effects of flow conditions and emulsion properties, such as shear rate, initial droplet size, viscosity and type of surfactant can be investigated in detail. Recently developed, fast (3-10 s) [82, 83] PFG NMR methods of measuring droplet size distributions have provided nearly real-time droplet distribution curves during evolving flows such as emulsification [83], Studies of other destabilization mechanisms in emulsions such as creaming and flocculation can also be performed. 

P Becher. Testing of emulsion properties. In Emulsions Theory and Practice, 2nd ed. New York Reinhold Publ. Co., 1957, pp 381 129. 

J.L. Salager Evolution of Emulsion Properties Along a Transitional Inversion Produced by a Temperature Variation. In Proceedings of the 3rd Word Congress on Emulsions l-F-094, Lyon, France (2001). 

P. Perrin and F. Lafuma Low Hydrophobically Modified Poly (Acryhc Acid) Stabilizing Macroemulsions Relationship Between Copolymer Structure and Emulsions Properties. J. Colloid Interface Sci. 197, 317 (1998). 

T.G. Mason, A.H. Krall, H. Gang, I. Bibette, and D.A. Weitz Monodisperse Emulsions Properties and uses. P. Becher (ed). Encyclopaedia of Emulsion Technology, Ch. 6, p. 299, Marcel Dekker, New York, Basel, Hong Kong (1996). 

Ercelebi, E.A., Ibanoglu, E. (2007). Influence of hydrocolloids on phase separation and emulsion properties of whey protein isolate. Journal of Food Engineering, 80, 454 159. 

Caessens, P.W.J.R., de Jongh, H.H.J., Norde, W., Gruppen, H. (1999). The adsorption-induced secondary structure of p-casein and of distinct parts of its sequence in relation to foam and emulsion properties. Biochimica et Biophysica Acta, 1430, 73-83. 

Multiple regression analysis is a useful statistical tool for the prediction of the effect of pH, suspension percentage, and composition of soluble and insoluble fractions of oilseed vegetable protein products on foam properties. Similar studies were completed with emulsion properties of cottonseed and peanut seed protein products (23, 24, 29, 30, 31). As observed with the emulsion statistical studies, these regression equations are not optimal, and predicted values outside the range of the experimental data should be used only with caution. Extension of these studies to include nonlinear (curvilinear) multiple regression equations have proven useful in studies on the functionality of peanut seed products (33). 

Specifications and Standards. Borax stability is an important property in adhesives, paper, and textile applications. Ollier emulsion properties tabulated by manufacturers include tolerance to specific solvents, surface tension, minimum film-forming temperature, dilution stability, freeze-thaw stability, percent soluble polymer, and molecular weight. 

Disadvantages Many factors other than hydrophobicity influence emulsion properties. It is essential that researcher determine that this test actually correlates with desired property of emulsion. 

The goal of food emulsion manufacturers is to produce emulsions that meet or exceed the expectations of their clientele. As a first step, companies typically conduct market studies to determine what these expectations are. Sensory evaluations are then used to translate these expectations into product-specific criteria (e.g., emulsion color, texture, appearance) that serve as guidelines to design the emulsification process and verify the quality of the produced emulsion. If emulsion properties comply with the set standards (i.e., their values are within an acceptable range), manufacturers can be confident that their customer base will be satisfied with the product. 

This example demonstrates that storage stability tests are extremely useful as they allow emulsion manufacturers to accurately follow even small changes in emulsion properties. Plots of droplet size distribution and concentration as a function of time can be used to determine the kinetics of the instability process and to determine the shelf life of the product by setting upper and lower limits for both mean droplet size and concentration at each port. 

An assessment of emulsion stability involves the determination of the time variation of some emulsion property such as those described in the physical characteristics section above. The classical methods are well described in Ref. [9]. Some newer approaches include the use of pulsed nuclear magnetic resonance or differential scanning calorimetry [294]. 

The distinguishing feature of membrane emulsification technique is that droplet size is controlled primarily by the choice of the membrane, its microchannel structure and few process parameters, which can be used to tune droplets and emulsion properties. Comparing to the conventional emulsification processes, the membrane emulsification permits a better control of droplet-size distribution to be obtained, low energy, and materials consumption, modular and easy scale-up. Nevertheless, productivity (m3/day) is much lower, and therefore the challenge in the future is the development of new membranes and modules to keep the known advantages and maximize productivity. 

Droplet-size distribution and disperse-phase percentage determine the emulsion properties characterizing the final formulation for an intended use. 

The surfactant selection determines the emulsion properties, such as stability, particle size, viscosity, and internal phase content. A correct balance between the hydrophobic and hydrophilic character of the emulsifier is necessary for minimizing the surfactant concentration at the resin-water interface. The surfactants used in resin emulsification can be ionic (in most cases anionic), nonionic, polymeric, or a combination of these. 

The stability of an emulsion denotes its ability to resist changes in its properties over time (i.e., higher emulsion stability implies slower change in emulsion properties). When considering the stability of an emulsion, it is of major importance to distinguish between thermodynamic stability and kinetic stability. Thermodynamics predict whether or not a process will occur, whereas kinetics predict the rate of the process, if it does occur. All food emulsions are thermodynamically unstable and thus will break down if left long enough. 

Malmsten, M., Bergenstahl, B., Nyberg, L., Odham, G. 1994. Shingomyelin from milk -characterization of liquid crystalline, liposome and emulsion properties. J. Amer. Oil Chemist Soc. 71, 1021-1026. 

Chemical finishes are often pad applied to dyed or printed fabrics after a drying step. In this situation, dry fabric is passed through the chemical finish solution and the process is called a wet on dry process. The wet pickup of a chemical solution in a pad mangle is influenced by many factors such as fabric characteristics, machine settings and solution or emulsion properties. Table 2.1 summarises some of these factors. 

Amphiphihc polybetaines that are end-capped by fluoroalkyl chains and which possess imique properties imparted by the fluorocarbon fragments were developed [234-236]. The polymers of common structure [Rp-26-Rp], [Rp-23a-Rp], and [Rp-(APDMAE) -Rp] (where APDMAE is 2-(3-acrylamidopropyldimethylammonio)-ethanoate and Rp is fluorinated hydrocarbons) were shown to exhibit a wide variety of dispersing, aggregate, and emulsion properties. The viscosity of [Rp-(APDMAE) -Rp] in water consid-... 

Making Emulsions. Much of this chapter is concerned with emulsion properties and stability, and as a practical matter chemists frequently have to contend with already-formed emulsions. Nevertheless, a few comments on how emulsions may be made are appropriate. The breaking of emulsions will be discussed later. 

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