Water-in-oil dispersion

Modem oil spill-dispersant formulations are concentrated blends of surface-active agents (surfactants) in a solvent carrier system. Surfactants are effective for lowering the interfacial tension of the oil slick and promoting and stabilizing oil-in-water dispersions. The solvent system has two key functions (1) to reduce the viscosity of the surfactant blend to allow efficient dispersant application and (2) to promote mixing and diffusion of the surfactant blend into the oil film [601]. 

Oil gels, blends with styrenic block copolymers, 24 715 Oil in water dispersions, 22 725 Oil-in-water (O/W) emulsions, 11 551 24 155... 

Where Co and Ce are the initial and equilibrium concentrations (mg mL ) of oil solution, respectively, V is volume of oil-in water dispersions (mL) and m the amount of adsorbent in gram. 

The dynamics of oil-in-water dispersion (OWD) are complex and have relevance related to potential toxicity or hazard. In comparing the toxicides to marine animals of oil-in-water dispersions prepared from different oils, not only the amount of oil added but also the concentrations of oil in the aqueous phase and the composition and dispersion-forming characteristics of the parent oil must be taken into consideration. In comparing the potential impacts of spills of different oils on the marine biotic community, the amount of oil per unit water volume required to cause mortality is of greater importance than any other aspect of the crude oil behavior. 

All the couplers used in colour photography contain an active centre, e.g. a methylene group, that can react with the quinone diimine to produce the azomethine dye as shown in Figure 2.31. The couplers need to remain anchored in their respective layers. The preferred method for meeting this requirement is to have medium-sized hydrophobic groups attached to the molecules. These hydrophobic couplers are introduced into the appropriate layer as oil-in-water dispersions. ... 

Water-removable ointments and creams are basically hydrophilic-type emulsions. They are prepared by fusion followed by mechanical addition approach. Hydrocarbon components are melted together and added to the aqueous phase that contains water-soluble components with constant stirring until the mixture congeals. A hydrophilic emulsifying agent is included in the aqueous phase in order to obtain stable oil-in-water dispersion. Sodium lauryl sulfate is used in the preparation of hydrophilic ointment USP. 

After the stirring rate had been established, the mixture, which should be an oil-in-water dispersion (not the reverse) was heated to 70 1°C under an atmosphere of nitrogen over a period of one hour. Before heat-up, the flask was fitted with a water-cooled condenser, a heating mantle, and a Jack-O-Matic from I R or a comparable device to provide heating and cooling as demanded by the polymerization reaction. The temperature of 70 1°C was maintained for four hours at the set stirring rate. During this... 

Fig. 3 Dual impeller arrangement for oil-in-water dispersion. Propeller is downward pumping. (From...

As previously discussed, placing a radial disk or Rush-ton turbine in the aqueous or lower phase, close to the interface, can be effective when making oil-in-water dispersions. A central interfacial vortex forms with the commencement of impeller motion. This directs a stream of the lighter oil phase to the impeller where it disperses. The volume of the oil layer decreases with continued dispersion until it is exhausted. Placing the turbine in the oil or upper phase, close to the interface, can result in water-in-oil dispersions, because a water-containing vortex forms, allowing water to be dispersed into the lighter oil phase. 

If the driving force (Ay) is less than zero an oil-in-water dispersion forms, while if Ay is of the opposite sign an inverse (water-in-oil) dispersion is produced. The stability threshold represents a critical emulsifier concentration below which a kinetically stable macroemulsion is produced. These can be transformed,... 

Poly (vinyl alcohol-co-vinyl acetate) polymers are surface active species which can be used to stabilise latex and oil in water dispersions. In order to understand the properties of these materials, it is necessary that their sequence distributions are well characterised. A number of NMR studies on the microstructure of PVA/PVAc copolymers have been made [51-53] (see also chapter 3). Moritani and Fujiwara [51], for example, have used proton and carbon-13 NMR spectroscopy to extract dyad distributions for a range of copolymers with different degrees of deacetylation. Samples were prepared using one of three routes direct saponification of PVAc alcoholyis of PVAc using sodium methoxide and reacetylation of PVA. From the polymer composition and the dyad distribution, the parameter rj was calculated for each polymer as follows ... 

P-carotene Nanoparticles by oil-in-water dispersion Protection of the agent against oxidation 71... 

In general, any hydrophobic organic compound can be dispersed or emulsified with the aid of suitable dispersants and strong shear forces to form an oil-in-water dispersion or emulsion. The amount of energy which is... 

Figure 8-13 Maximum drop size dmax versus local power draw for dilute oil-in-water dispersions. The local power per mass of fluid is the total power input divided by the mass of fluid in the high intensity dispersion region of the mixa-. (After Davies, 1987.)...

Production of Solid-in-Oil-in-Water Dispersions 143 Production of Double Emulsions Using Microfluidic Devices 144 Production of Solid Microparticles Via Double Emulsions Using Membrane and Microfluidic Devices 149... 

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