Emulsions physical characteristics

The HLB system has made it possible to organize a great deal of rather messy information and to plan fairly efficient systematic approaches to the optimiza-tion of emulsion preparation. If pursued too far, however, the system tends to lose itself in complexities [74]. It is not surprising that HLB numbers are not really additive their effective value depends on what particular oil phase is involved and the emulsion depends on volume fraction. Finally, the host of physical characteristics needed to describe an emulsion cannot be encapsulated by a single HLB number (note Ref. 75). 

Styrene is a colorless Hquid with an aromatic odor. Important physical properties of styrene are shown in Table 1 (1). Styrene is infinitely soluble in acetone, carbon tetrachloride, benzene, ether, / -heptane, and ethanol. Nearly all of the commercial styrene is consumed in polymerization and copolymerization processes. Common methods in plastics technology such as mass, suspension, solution, and emulsion polymerization can be used to manufacture polystyrene and styrene copolymers with different physical characteristics, but processes relating to the first two methods account for most of the styrene polymers currendy (ca 1996) being manufactured (2—8). Polymerization generally takes place by free-radical reactions initiated thermally or catalyticaHy. Polymerization occurs slowly even at ambient temperatures. It can be retarded by inhibitors. 

Approximate number of theoretical stages for extraction and stripping The necessity or desirability of a scrub stage between extraction and stripping The physical characteristics of the system i.e., dispersion requirements and settling rates, emulsion tendencies, viscosity, etc. 

Following preliminary hypochlorite treatments, a coherent process path was identified and implemented. Corn starch was oxidized with 6.4% (w/w) hypochlorite for two hours and given a combined base-heat gelatinization process (Method A). This base material exhibited excellent physical characteristics (i.e., stable emulsion with 20% db lemon oil incorporation into an aqueous dispersion, low lemon oil vapor phase flux (low headspace content), lack of inherent flavor and aroma) and when finally tested for spray dried lemon oil (20% db) retention efficiency in a lab-scale mini-dryer, the viability of this polymer was ascertained. Nearly 70% of the added lemon oil was retained following the drying of this DE 1.45 starch, a measure of functionality matched only by gum arabic (34). 

This chapter describes some methods to study physical characteristics and ingredient interactions in whippable dairy-based emulsions. The story of whippable emulsions begins with natural dairy cream. From this starting point a range of dairy-type whippable emulsions has been developed over the years. 

In the last year a new formulation of aminocarb has appeared on the insecticide market. It is finely ground aminocarb suspended in an oil and it has the advantage that it can be tank mixed to give either an oil or a water suspension. Studies (10) show that, like the oil solution, this product has a half life in the same range (3.2 to 6.0 days). There was an indication of a variation in the initial rate of loss due to the physical characteristics of the water emulsion spray (in a series of repeat studies the evaporation rate was not constant). The presence of the emulsifier inhibited evaporation resulting in a higher initial foliar deposit than with the oil base spray. The occurence of the lower rate of deposit of the oil spray can be attributed to the particular oil used in the Canadian budworm sprays. To meet the concerns of the health authorities the standard No. 2 and No. 4 fuel oils which had been used are now prohibited. The accepted product, known as Insecticide Diluent 585 is volatile with an evaporation rate approaching that of water. 

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 interfacial films formed by different crude oils have different characteristics. The physical characteristics of the films are a function of the crude-oil type and gas content, the composition and pH of water, the temperature, the presence of nonionic polar molecules in the water, the extent to which the adsorbed film is compressed, and the contact time allowed for adsorption and concentration of polar molecules in the oil phase 14, 22,23). The rheological properties of the adsorbed emulsifier film have an important effect on the stability of emulsions. 

Changing the physical characteristics of an emulsion by the addition of diluents or water. 

The first theory claims that the particles are surface active but, unlike surfactants, are not amphiphilic. Partially modified particles preferentially partition the interface between the two phases, with the key physical characteristic for stabilization being the contact angle of the individual particle with the interface. Particles having a 90° contact angle (approximately equal amounts of hydrophobic and hydrophilic character) with the interface will create the most stable emulsions. The particles used in these studies are nanometer sized ( 10-30 nm), but this is the primary particle size. The particles are actually agglomerated and are typically several hundred nanometers in size. This distinction is important for... 

The answer is a. (Murray, pp 627-661. Scriver, pp 3897-3964. Sack, pp 121-138. Wilson, pp 287-320.) Vitamins A, D, E, and K are all fat-soluble. The physical characteristics of fat-soluble vitamins derive from the hydrophobic nature of the aliphatic chains composing them. The other vitamins listed are water-soluble, efficiently administered orally, and rapidly absorbed from the intestine. Fat-soluble vitamins must be administered intramuscularly or as oral emulsions (mixtures of oil and water). In intestinal disorders such as chronic diarrhea or malabsorption due to deficient digestive enzymes, fat-soluble vitamins are poorly absorbed and can become deficient. Supplementation of fat-soluble vitamins is thus routine in disorders like cystic fibrosis (219700), a cause of respiratory and intestinal disease that is the likely diagnosis in this child. 

In microfluidic devices, multiphase flows are created when two (or more) immiscible fluids come into contact. Depending on the interaction between the mterfacial and viscous forces, the resulting multiphase flow can take different forms, such as suspended droplets, slugs (droplets occupying the whole channel) or stratified flow (parallel) [141, 142]. In addition to the forces exerted between the two liquids, the channel geometry and physical characteristics also play an important role in the process [143]. In this respect, the use of hydrophobic channels is suitable for the formation of water-m-oil emulsions, whereas hydrophilic channels favor the creation of oil-m-water emulsions [144]. 

We, of course, recognize the fact that miik contains diftcrent animal bodies not present in ordinary artificial emulsions, which are prone to decomposition, so that the similarity drawn between the two is based more upon physical characteristics than their presenting any features in common chemically. 

Chung, H. et al.. Oil components modulate physical characteristics and function of the natural oil emulsion as drug or gene delivery system, J. Contr. Rel., 71, 339, 2001. Lehrm, C. et al., Alkylcyanoacrylate drug carriers. II. Cytotoxicity of cyanoacrylate nanoparticles with different aUcyl chain lengths, Int. J. Pharm., 84, 13, 1992. 

In the petroleum industry, not all W/O emulsions are the same. The nature of emulsions formed in crude oil often depends on many factors the geologic source and the engineering processes utilized in the crude oil recovery, the chemical and physical characteristics of the crudes and their thermal history, the type of mixing and energy introduced,... 

Finally, creaming is a process which is related to flocculation in that it occurs without the loss of individual drop identities (Fig. 11.2d). Creaming will occur over time with almost all emulsion systems in which there is a difference in the density of the two phases. The rate of creaming will be dependent on the physical characteristics of the system, especially the viscosity of the continuous phase. It does not necessarily represent a change in the dispersed state of the system, however, and can often be reversed with minimal energy input. If the dispersed phase happens to be the more dense of the two phases, the separation process is termed sedimentation. 

Condition of the feed material, that is, the concentration, physical characteristics, and temperature at which the solution/emulsion to be dried reaches the drum surface... 

Treating processes and equipment should not be selected until the physical characteristics of the oil and water have been determined and a study of the effect of available chemicals on the emulsion has been made. 

Small amounts of solids in produced water may or may not create problems in water treating depending on the particle micron size and its relative attraction to the dispersed oil. If the physical characteristics and electronic charge of such solids result in an attraction to the dispersed oil droplets, the solid particles can attach to the dispersed oil droplets to stabilize emulsions, thereby preventing coalescence and separation of the oil phase. The combined specific gravity of the resulting oil/solid droplet can be approximately equal to that of the produced water, and gravity separation becomes difficult if not impossible. 

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