Emulsification protocol

An accurate formulation handling is extremely useful not only to make microemulsion and to adjust their properties such as their solubilisation ability, or to attain a low interfacial tension to ease emulsification or to enhance oil recovery. Formulation has been shown to be also directly linked with emulsion properties such as their type, stability, viscosity, drop size [6] and with the efficiency of the emulsification protocol [7]. The existence and persistence of foams are dependent on formulation too [8]. Solid surface wetting is also linked with formulation as well as with many related applications. This is why an accurate numerical treatment of formulation issues is paramount in industrial research and development. 

Other emulsification protocols are based on a transient phenomenon, in which a dominant role is played by an unsteady mechanism, e.g., rrutss transfer through interface, which is not easy to ascertain or control. Often the nonequilib-riuin is driven by a continuously programmed change in a single variable such as temperature, amount or type of surfactant, watcr-to-oil ratio, etc., so that a phase behavior fionlicr is crossed and some event such as an emulsion inversion... 

The emulsion drop size depends on such a high number of different variables that it is difficult to separate and impute ail effects. In what follows a standard emulsification protocol is applied to a preequilibraied system, so that the change in drop size is only due to formulation or composition effects, or their direct consequences on other properties such as tension, stability, and viscosity. In fact, very few maps have been experimentally determined and only trend.s are available (SI.92). 

Lopez-Montilla, J.C., James, M.A., Crisalle, D.O. and Shah, D.O. (2005). Surfactants and protocols to induce spontaneous emulsification and enhance detergency. J. Surfactants Detergents, 8(1), 45-53. 

EMAA ionomer (0-30 parts) dispersed phase particle size vs. interfacial modifier concentration / emulsification curves / effects of mixing protocol / also blends containing PP in place of HDPE Favis, 1988... 

Favis [1994] and Willis andFavis [1988] prepared compatibilized PA blends with PP and carboxylic acid-functionalized EMAA ionomer. Blends containing 90-10 parts PA-6, 0-30 parts EMAA ionomer, and 10-90 parts PP were combined in an internal mixer at 250°C and characterized by torque rheometry and SEM. Dispersed phase particle size vs. interfacial modifier concentration was determined. Emulsification curves were constructed. Effects of mixing protocol on blend properties were studied. Blends were also prepared containing HOPE in place of PP. 

Emulsification and demulsification are both eomplex processes. However, as noted earlier, demulsifieation is by no means the opposite of emulsification (200,201). This is especially the case in the petroleum industry. In order to demulsify a crude W/O emulsion efficiently, it has been emphasized that it is advantageous to understand first the characteristics of the emulsions, the nature of interfaeial films, and hence the causes of stability. Accordingly, in choosing a demulsification protocol, one would first identify key factors responsible for the stabihty, find the target properties to modify toward destabilization, introduce sufficient energy to promote coalescence, and find the best conditions to allow phase separation. 

Summary Silicones with substituents from natural sources can be synthesized following simple protocols. The modification can be either hydrophilic, oleophilic or both. As hydrophilic substituents carbohydrates and polyethers are used, as oleophilic substituents cholesterol and simple alkyl chains. The physicochemical properties, such as viscosity, reduction of surface tension and emulsification performance, of silicones with standard modifications and of silicone modifications with substituents fit>m natural sources are significantly different. 

The emulsions discussed in the previous sections were prepared at fixed formulation and composition in the map. In practice, the formulation and composition of a system can change as time elapses or as emulsification proceeds. For instance, one of the phases could be added little by little, such as oil drops in a homemade mayonnaise preparation. In another case, the formulation or temperature could be changed according to certain programming protocol as in emulsion pol5unerization. 

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