Emulsion history

Gupta, D.V.S., Leshchyshyii, T.T., Hhdek, B.T. Surfactant gel foam/emulsions History and field application in the western Canadian sedimentary basin. Source Proceedings—SPE Annual Technical Conference and Exhibition, p 4543-4549, 2005, Proceedings—SPE Annual Technical Conference and Exhibition, ATCE 2005. 

The early history of redox initiation has been described by Bacon.23 The subject has also been reviewed by Misra and Bajpai,207 Bamford298 and Sarac.2,0 The mechanism of redox initiation is usually bimolecular and involves a single electron transfer as the essential feature of the mechanism that distinguishes it from other initiation processes. Redox initiation systems are in common use when initiation is required at or below ambient temperature and drey are frequently used for initiation of emulsion polymerization. 

History. The first attempts to desensitize RDX were reported by Frankel and Carle ton (Refs 1 thru 5) who made use of polymeric materials such as polyurethanes to coat expl crysts by means of emulsion or soln techniques. The first true PB-RDX was developed in 1952 at the Univ of Califs Los Alamos Lab and consisted of RDX coated with polystyrene plasticized with DOP (Refs 6 21). Since then the Lawrence Livermore Lab has evolved a series of PBX formulations, many of which are listed in Tables 3,4 5. These compns are described in Ref 77... 

Acids were an early exception to the no water rule. It was recognized that aqueous solutions of acids would inhibit swelling of clays and shales as well as dissolve any acid-soluble minerals contained in a formation. By 1933 commercial well stimulation with hydrochloric acid was of great interest. A whole separate methodology and treatment chemistry has since evolved around acidizing and fracture acidizing(54). Water emulsions, mainly emulsified acids, and gelled acids thickened with polymeric additives were applied early in the history of well treatment. 

Figure 1 shows conversion-time histories for batch emulsion VCM reactors from (70). The recipes used consisted of 1.0 liter of water, 0.47 liters of VCM and varying amounts of soap and initiator, as indicated on the figure. For the cases of Figure lb, Berens (70) measured 0.68 x 101 particles per liter of latex for the upper curve (I = 1.0 gr, S = 3.0 gr) and 0.34 x 1017 for the lower one corresponding to I = 1.0 gr and S = 1.15 gr. Our model s predictions were 0.2 x 1018 and 0.14 x 1017, respectively. In Figure la, the same amount of emulsifier was used for both runs. Berens (70) estimated 0.38 x 1017 particles per liter of latex for both cases, while our model s prediction was close to 0.22 x... 

Figure 1. Conversion-time histories in batch PVC emulsion polymerization for different initiator and emulsifier concentrations.

Patient case A patient s daily nutritional requirements have been estimated to be 100 g protein and 2,000 total kcal. The patient has a central venous access and reports no history of hyperlipidemia or egg allergy. The patient is not fluid restricted. The PN solution will be compounded as an individualized regimen using a single-bag, 24-hour infusion of a 2-in-1 solution with intravenous fat emulsion (IVFE) piggybacked into the PN infusion line. Determine the total PN volume and administration rate by calculating the macronutrient stock solution volumes required to provide the desired daily nutrients. The stock solutions used to compound this regimen are 10% crystalline amino acids (CAA), 70% dextrose, and 20% IVFE. 

Emulsion polymerization has a history of half a century in science and much more in industry. There seem to be few undissolved subjects in general emulsion polymer-... 

Experience is a very useful teacher in selecting demulsifiers. The man who is familiar with the history of treating m an area, the demands of the treating plants, and the performance of the chemicals can do a pretty good job ot picking compounds. However, this approach fails when changes occur in emulsion characteristics, new emulsions are encountered, or new chemicals become available. 

Polyfvinyl acetate) (PVAc) latexes produced by batch and continuous emulsion polymerization were used in this study. Details for the apparatus and the polymerization procedure can be found in Penlidis et al. (6,12,K3). Samples taken during the reaction were subsequently analyzed to follow conversion- and particle growth-time histories. The batch experimental runs were designed to yield similar conversion-time histories but different particle sizes. Conversion was measured both off-line, by gravimetric analysis, and on-line using an on-line densitometer (a U-tube DPR-YWE model with a Y-mode oscillator with a PTE-98 excitation cell and a DPR-2000 electronic board by Anton Paar, Austria). A number of runs were repeated to check for reproducibility of the results. Four batch runs are described in Table I below and their conversion histories are plotted in Figure 1. 

Specific turbidity histories are also plotted vs. dimensionless time for a continuous emulsion polymerization run the samples were withdrawn from the second reactor of a continuous train where the first reactor is a small seeding reactor. Part A of Figure 3 shows the particle size behaviour during start up all monomer, water, initiator and soap feedrates were kept constant until the process reached a steady state. In part B, the soap concentration in the seed reactor was increased a decrease in the particle size was expected and it is clearly shown from the specific turbidity measurements. 

Figure 1. Conversion histories of the batch vinyl acetate emulsion polymerizations (similar recipes only the emulsifier concentration is different).

Since the polymerization conditions for styrene and methyl methacrylate often are chosen such that a in the early stages of polymerization (after N has become constant) lies between 10 2 and 1, it is understandable that gel-effect usually is important in emulsion polymerization of these monomers and therefore must be accounted for since it completely dominates the shape of the conversion history. 

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