Emulsion of two

The production of polymeric HYAFF microspheres loaded with the pharmaceutical is currently performed by solvent emulsion precipitation [4], This process requires the preparation of an emulsion of two immiscible liquids. The polymer and the co-precipitated pharmaceutical can be inactivated or degraded due to the temperature that is required for solvents removing. Moreover, a complete separation of the residual solvents cannot be achieved and a relevant percentage of liquid is retained within the final product. Finally, liquid solvent and antisolvent cannot be recovered. 

Here you find the pastes. Hazelnut paste is a dispersion of particles in a thick emulsion of two liquids, as is peanut butter. Jam is thickened by natural polymers. Soft cheese, butter and margarine are in the refrigerator these are complicated structures of fat crystals, oil, water and many other components. All these pastes have a yield stress that is low enough to let them be spread by a knife, but not so low that they run off bread. Users do find the cold butter a bit stiff and the jam a bit thin. As a developer you might want to improve these things. Bread - a solid foam - is a surprising structure when looked at it closely. Fresh bread is often too soft to cut easily. 

Below this line, however, the temperature must be raised sufficiently to maintain the emulsion of two liquids this is shown by the curved... 

Figure 14. Changes in apparent fluid permeability when Boise sandstone was flooded with an emulsion of two different droplet sizes. (Reproduced with permission from reference 9. Copyright 1973 Society of Petroleum Engineers.)...

Microparticles can be produced from emulsion of two or more immiscible liquids. For example, a... 

Let us assume that the total free energy of the emulsion can be separated into several independent contributions. Considering hypothetically the formation or coalescence of emulsion of two immiscible liquids (e.g. oil and water), such that external field forces are absent. The total free energy (Gg) of the system just before emulsification process can be expressed in the form (10)... 

Stable concentrated oil-in-water emulsions of two viscous crudes were made by adding NaOH which reacts with acids present in the oils. 

Liquid membranes consist of an emulsion of two immiscible phases dispersed in an external, continuous phase (33) (Figure 3). 

Rubber particle size is extremely important to make an optimized impact product. Particles that are both too small and too large cause a loss of impact strength. The ability to form stable particles of optimum size depends on the graft that functions as an oil in oil emulsion. This might better be referred to as an emulsion of two incompatible organic phases. To size the rubber particles, shearing agitation must be provided. If it is not provided, phase inversion does not occur, and a cross-linked continuous phase that produces gel is the result. 

Liquid membranes are made by forming an emulsion of two immiscible phases and then dispersing it in a third phase (the continuous or donor phase). Frequently, the encapsulated (or receiving) phase and the continuous phase are miscible. The membrane phsse must not be miscible with either if it is to remain... 

Emulsion Stability. An emulsion is defined as a macroscopic dispersion of two liquids, one of which forms the continuous phase of the system and the other forms the discrete phase. An emulsion of two liquids without a stabilizer will quickly break into two liquid layers. Emulsions destabilize by three distinct processes breaking, creaming, and flocculation (Figure 14). When emulsions break, the initial small droplets of the emulsion spontaneously join to form larger droplets. This process is termed coalescence , and it ultimately leads to two separate liquid layers. 

On the other hand, concentrated systems (( > > 0.7) can be expected to develop higher yield stresses and viscoelasticity as droplet size decreases (18,19). Figure 24 shows how the storage modulus G augments when increasing and decreasing droplet size, for waicr-in-oil emulsions of two different droplet sizes. 

Figure 24 Elastic modulus. C. as a function of internal phase content for water-in-oil emulsions of two different droplet sizes, fine and coarse. (Adapted from Ref. 19.)...

Fig. 4 Lower IR HC readings after Ftorisil for emulsions of two naphthenic crudes...

The Gibbs-Marangoni effect would also explain Bancroft s rule when making an emulsion of two phases, the one in which the surfactant is most soluble will become the continuous phase. If the surfactant is in the droplets, a y-gradient as depicted in Figure 2.12b would never develop, and the drops would be prone to coalescence. Hence, surfactants with an HLB value >7 tend to produce O/W emulsions those with HLB < 7, W/0 emulsions. 

In the second place the interaction of the double layers of two droplets of an emulsion will determine the stability of the emulsion A complete description of this effect offering still more mathematical difficulties than the interaction of two spherical double layers as treated in 4 will not be aimed at, as a superficial consideration will already be sufficient to demonstrate that the energy of interaction between two droplets of an emulsion is much smaller than that between solid particles This explains why emulsions of two pure liquids are never stable (c/ chapter VIII, 11, p 336) and why the addition of emulsifiers is necessary to prepare stable emulsions Let us first consider the meeting of... 

It. lias been shown in chapter VI 7, p. 261 that the repulsion between two oil droplets in water or between two water droplets in oil is much smaller than the repui->ion between two solid particles covered with a double layer. Therefore emulsions of two pute liquids arc never stable. It is possible to prepare and investigate such emul-sums m an extt emely dilute form, so that the flocculation time will be very large, but a reasonably stable emulsion can only be prepared by the addition of at least one component more to the system. This third component should be chosen in such a way as to ch mge the double diffuse double layer at the oil water interface into a normal double layer m the w ater phase only. 

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