Emulsion conditions

For the synthesis of carbohydrate-substituted block copolymers, it might be expected that the addition of acid to the polymerization reactions would result in a rate increase. Indeed, the ROMP of saccharide-modified monomers, when conducted in the presence of para-toluene sulfonic acid under emulsion conditions, successfully yielded block copolymers [52]. A key to the success of these reactions was the isolation of the initiated species, which resulted in its separation from the dissociated phosphine. The initiated ruthenium complex was isolated by starting the polymerization in acidic organic solution, from which the reactive species precipitated. The solvent was removed, and the reactive species was washed with additional degassed solvent. The polymerization was completed under emulsion conditions (in water and DTAB), and additional blocks were generated by the sequential addition of the different monomers. This method of polymerization was successful for both the mannose/galactose polymer and for the mannose polymer with the intervening diol sequence (Fig. 16A,B). 

The initial polymerizations were conducted with both homogeneous and emulsion conditions. In the homogeneous reactions, a mixture of metha-nolrdichloroethane was used to dissolve the sulfated monomer, and the initiator was introduced as a solution in dichloroethane. These reactions did not proceed to completion, even upon heating. During the reaction, the formation of a precipitate was observed, which could be attributed to the growing polymer chain. Although the monomer is soluble in methanol as a triethylammonium salt, the... 

Fig. 18. Sulfated carbohydrates were polymerized under emulsion conditions using the defined ruthenium catalyst to provide glycoprotein mimics... 

At least a very low water solubility of the monomer is required. Extremely hydrophobic monomers, e.g., stearyl acrylate, do not polymerize under emulsion conditions. 

Under certain conditions, fuel detergents, corrosion inhibitors, and other performance-enhancing additives can emulsify with water to form water-in-oil emulsions. Conditions of low pH, high pH, or high additive concentration may enhance the emulsification of polar organic compounds into fuel. 

Desalter units generally will produce a dehydrated stream containing like amounts of BS W from each stage. Therefore, BS W can be considered pan through volume and the dilution water added is the amount of water to be recycled. The recycle pump, however, generally is oversized to com- >cnsate for difficult emulsion conditions and upsets in the system. 

Ozonization of benzo[< pyrcnc in dodecane/water emulsions (conditions modeling those in contaminated ground-water or industrial wastewater) is shown to yield an ozonide and an oxepinone <2001MI231>. 

Kanno, C. 1989. Emulsifying properties of bovine milk fat globule membrane in milk fat emulsion conditions for the reconstitution of milk fat globules. J. Food Sci. 54, 1534-1539. 

Redox systems which have been the subject of recent examlnC atlon include potassiian permanganate - tartaric acid ( ), and potassium persulfate — ascorbic acid.( ) Whilst experiments were with the water soluble acrylamid they should be adaptable to emulsion conditions. The ascorbic acid reductant is of inters est as it is not interfered with by air or monomer stabilisers. 

For obvious reasons, cationic and anionic polymerizations, as well as any other technique that propagates through water-sensitive intermediates, are not applicable to emulsion conditions. Currently, only radical emulsion processes are used commercially. 

A wider range of acrylate/styrene block copolymers have been prepared by copper catalysts, partially because the homopolymerizations of both monomers can be controlled with common initiating systems. Both AB- (B-15 to B-17)202,230,254,366,367 and BA-type (B-18 to B-21)28,112,169,230,366,368,369 block copolymers were obtained from macroinitiators prepared by the copper-based systems. The block copolymerizations can also be conducted under air230 and under emulsion conditions with water.254 Combination of the Re-and Ru-mediated living radical polymerizations in... 

Hydrolyses have also been conducted in micro-emulsions, using non-ionic surfactants. In this case, self-assembled tin-based hydrid materials are prepared, regardless of the nature of the precursor molecule (Table 3.2.4). Micro-emulsion conditions are therefore required to organize the hybrid containing the flexible alkylene spacers. 

Whereas the polyketones were usually reported to precipitate from the aqueous phase, under emulsion conditions latexes of ethylene-undecenoic acid-CO ter-polymers and of 1-alkene-CO copolymers can be obtained, which are film-forming at room temperature [12]. Using a miniemulsion technique (cf. Section 6.12.3), water-insoluble diphosphine ligands can be employed without the necessity for hydrophilic modification. 

RAFT is effective with a wide range of monomers, but distinguishes itself from SFRP and ATRP in that it can polymerize carboxylic acid-containing monomers such as methacrylic acid [46]. The polymerizations are performed at temperatures of 100 °C or less with typical polydispersities in the 1.1 1.25 range under either bulk, solution or emulsion conditions. Initially formed homopolymers can readily be chain extended or transformed into block copolymers by reaction with a second monomer [47]. 

We measured the heat of copolymerization in emulsion for copolymer containing 13.5 mole % styrene at 60°C. Measurements were made with a styrene feed at 20°C therefore, some reaction heat was used to warm the styrene to 60°C. Experiments indicated that this effect was partially compensated for by the heat of mixing because the mixing of styrene with the reactants was very slightly exothermic. If the styrene were preheated to 60°C, the effect would be to raise the measured heat of copolymerization by about 0.09 kcal./ mole. A value of 20.2 kcal/mole (i.e., 337 cal/g) was obtained for the heat of copolymerization. In order to elucidate this unexpectedly high finding, we also measured the heat of homopolymerization of acrylonitrile under similar emulsion conditions in the same apparatus a value of 22.1 kcal/mole was obtained. 

In order to represent more realistic emulsion conditions, Langmuir interfacial films adsorbed at the OAV interface were analyzed. The isotherms depicted in Fig. 11 illustrate some of the film properties of naturally occurring crude oil... 

Outstanding thickener and emulsifier. A broad range of compatibility allows its use in cold wave neutralizers, vegetable oil emulsions, conditioning shampoos and conditioning mousses. 

The catalysts can either be free-radical (usually allowed to react under emulsion conditions), anionic, e.g. Na (not used now, but originally used to give Buna rubber), alkyl lithium, Alfin (which is an insoluble mixture of Na, isopropanol and n-butyl chloride—the active species is probably a solvated alkyl sodium), or a Ziegler coordination system, such as Til4/A1R3, CoX2/AlEt2Cl/H20. 

Panels (8.9 x 15.2 x 0.235 cm) were cut consecutively, at all possible locations, from commercial chrome-tanned grain-split blue stock cattlehide. Untreated control panels were included with each treated panel. In the emulsion method, after a separate 30 min conditioning period with the potassium persulfate-sodium bisulfite redox initiator system, the panels to be treated were tumbled at ambient temperature under emulsion conditions with the appropriate monomer for 24 hr. Composite composition was obtained gravimetrically from methanol or air-dried panels. Homopolymer was removed from apparent bound polymer by hot benzene extraction. Standard conditions were water 5 1 based on dry leather ... 

Figure 5 Polymerization of monomers bearing unprotected carbohydrates using emulsion conditions, (a) Monomers with unprotected carbohydrate groups can be polymerized using defined initiator 8. (b) Bioactive polymers can be generated under emulsion conditions.

Figure 11 Polymers displaying sulfated galactose derivatives are inhibitors of selectin-ligand interactions. The ability of the polymers to inhibit the binding of HL60 cells to immobilized selectins is reported as the concentration required for 50% inhibition (IC50). Polymers were generated using (a) homogeneous conditions or (b) emulsion conditions. For compounds for which IC50 values were not available, the percent inhibition at a particular concentration is reported.

Due to the high compatibility of water, TERP was applied to a mini-emulsion condition by Okubo. Polymerization of MMA, St, and BA under mini-emulsion condition was carried out under condition B with CTA Te-2 and AIBN as an initiator in an aqueous solution containing sodium dodecyl sulfate at 60 °C. In the case of MMA polymerization, dibutylditelluride was added to increase the MWD control. The polymerization proceeded in a controlled manner with a high monomer conversion and afforded stable latexes with controlled sizes, though the MWDs of the resulting polymers were broader (Mw/Mn= 1.23-1.76) than those obtained under homogeneous conditions. Diblock copolymers composed of St, MMA, and BA were prepared by using a two-step procedure, both of which were carried out in an aqueous dispersed system. 

Polyoxometalates (POMs) are transition metal oxygen clusters with well-defined atomic coordination structures. POMs are used as functional nano-colloidal materials and also as supports for catalysts via ion-pair interactions due to their acidic properties. Combinations of chiral diamines and POM 225 effectively catalyze enamine-based aldol reactions. Less than 1 mol% of chiral amine loading is suf-ficientto catalyze the reaction (Table 28.10, entries 1 and 2) [114]. Highly diastereo-and enantioselective cross-aldol reactions of aldehydes are accomplished using chiral diamine-POM 226 under emulsion conditions (entries 3 and 4) [115]. Sul-fonated polystyrene or fluoropolymer Nafion NR50 are also good supports for the immobilization of primary-tertiary diamines. The catalyst 227 can be recovered by filtration and reused for at least four cycles with no loss of stereoselectivity (entries 5 and 6) [116]. 

Uses Thickener, emulsifier for personal care prods, incl. cold wave neutralizers, veg. oil emulsions, conditioning shampoos and mousses Properties Solid 100% cone. 

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