Emulsion distribution ratio

A total of 0.50 g of benzoic acid was added to 200 mL of water at pH 5.2. 100 mL of benzene was then added to the aqueous phase and thoroughly mixed. How much benzoic acid remains in the oil phase of the emulsion as dimers The pKa of benzoic acid is 4.2. The apparent distribution ratio is 38.5. 

Variation in Emulsifier Distribution Ratio between Monomer Feed Emulsion and Initial Reactor Charge... 

Since emulsifiers determine the particle size of the latex, we studied the influence of the distribution ratio of the emulsifiers between monomer feed emulsion and initial reactor charge on the latex properties. We found that small amounts of the nonionic emulsifier in the initial reactor charge caused coagulation during latex preparation. Hence, the total... 

To gain a better understanding of this phenomenon we followed the number of particles in the reactor with time during the monomer emulsion addition for three different distribution ratios of the anionic emulsifier. The ratios 40/60, 97/3, and 100/0 were chosen because they gave different particle sizes of the ultimate latex the first on the flat part of the curve in Figure 2, the second just in the bend, and the third on the... 

Mass distribution ratio in microemulsion electrokinetic chromatography, /cMeekc — Defined analogously to the -> mass distribution ratio (in - micellar electrokinetic chromatography), kMEKC, by replacing terms for micelles with corresponding terms for micro emulsion. 

Particle Size Distribution (Ratio of Volume to Number Average) for Polyvinyl Chloride Latices Produced by Radiation Induced Emulsion Polymerization... 

Solvent systems suitable for coimtercurrent distribution must always form two discrete liquid phases, and a finally divided suspension in one phase in the other must separate quickly into two bulk-liquid layers. These properties must be retained in the presence of appreciable amounts of sample. The two phases should, therefore, differ in density, neither should have a high viscosity, while the interfacial tension should not promote the formation of stable emulsions. Formation of emulsions, which separate only with difficulty with real samples, is the most serious practical problem. Solvent systems should be selected based on their selectivity for the separation. In addition, distribution ratios can be optimized by changing the phase ratio or distribution properties of the phases by using additives (e.g., pH, complexing agents, salts, polymers, etc.). 

In Fig. 21.43, the dependence of the oil drop size distribution on the ALR is shown for a constant plant oil emulsion viscosity ratio. The viscosity of the plant oil emulsion was 0.013 Pa s, which equals a viscosity ratio of 4. It may be seen that the oil drop size decreased with increasing ALR, which is in line with previous findings. This is caused by increased stress acting on the feed due to the higher gas velocity [9]. 

Eree-radical initiation of emulsion copolymers produces a random polymerisation in which the trans/cis ratio caimot be controlled. The nature of ESBR free-radical polymerisation results in the polymer being heterogeneous, with a broad molecular weight distribution and random copolymer composition. The microstmcture is not amenable to manipulation, although the temperature of the polymerisation affects the ratio of trans to cis somewhat. 

Distribution of the monomer units in the polymer is dictated by the reactivity ratios of the two monomers. In emulsion polymerization, which is the only commercially significant process, reactivity ratios have been reported (4). IfMj = butadiene andM2 = acrylonitrile, then = 0.28, and r2 =0.02 at 5°C. At 50°C, Tj = 0.42 and = 0.04. As would be expected for a combination where = near zero, this monomer pair has a strong tendency toward alternation. The degree of alternation of the two monomers increases as the composition of the polymer approaches the 50/50 molar ratio that alternation dictates (5,6). Another complicating factor in defining chemical stmcture is the fact that butadiene can enter the polymer chains in the cis (1), trans (2), or vinyl(l,2) (3) configuration ... 

V. Mishra, S. M. Kresta, J. H. Masliyah 1998, (Self-preservation of the drop size distribution function and variation in the stability ratio for rapid coalescence of a polydisperse emulsion in a simple shear field), J. Colloid Interface Sci. 197, 57. 

The preparation of a ferrofluid emulsions is quite similar to that described for double emulsions. The starting material is a ferrofluid oil made of small iron oxide grains (Fe203) of typical size equal to 10 nm, dispersed in oil in the presence of an oil-soluble surfactant. The preparation of ferrofluid oils was initially described in a US patent [169]. Once fabricated, the ferrofluid oil is emulsifled in a water phase containing a hydrophilic surfactant. The viscosity ratio between the dispersed and continuous phases is adjusted to lie in the range in which monodisperse fragmentation occurs (0.01-2). The emulsification leads to direct emulsions with a typical diameter around 200 nm and a very narrow size distribution, as can be observed in Fig. 1.33. 

In homogeneous copolymerization, the instantaneous composition of copolymer is decided only by monomer reactivity ratio. On the contrary, in emulsion copolymerization, the copolymer composition depends not only on the monomer reactivity ratio but also on the distribution of monomers between oil (polymer-monomer particles) and aqueous phases (18). 

Narrow droplet size distribution Larger droplets are less unstable than smaller droplets on account of their smaller area-to-volume ratio, and so will tend to grow at the expense of the smaller droplets (see page 68). If this process continues, the emulsion will... 

In addition to the surfactant and epoxy resin, the parameters of the emulsification process will significantly influence the properties of the final emulsion. To obtain the smallest achievable droplet size with a narrow droplet size distribution, it is essential to optimize process parameters such as temperature of emulsification and mix ratio of surfactants when more than one surfactant is used. 

The aim of this first section is to describe the rupturing mechanisms and the mechanical conditions that have to be fulfilled to obtain monodisperse emulsions. A simple strategy consists of submitting monodisperse and dilute emulsions to a controlled shear step and of following the kinetic evolution of the droplet diameter. It will be demonstrated that the observed behavior can be generalized to more concentrated systems. The most relevant parameters that govern the final size will be listed. The final drop size is mainly determined by the amplitude of the applied stress and is only slightly affected by the viscosity ratio p. This last parameter influences the distribution width and appears to be relevant to control the final monodispersity. 

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