Stearates effect

Some studies reported that polyoxyethylene (POE) stearates (under the brand name Myrj) and alkyl-polyethyleneoxide (PEO) surfactants (under the brand name Brij) can inhibit efflux pumps. The oral bioavailability of the P-gp substrate cyclosporine A administered in a solid dispersion of polyoxyethylene 40 stearate (Myrj 52) was in the same range as the oral bioavailability of the commercial product Sandimmune Neoral (Liu et al. 2006). In a study by Lo, it has been shown that apical to basolateral epirubicin transport across Caco-2 cells was enhanced in the presence of polyoxyethylene 40 stearate and the basolateral to apical transport was decreased. These results indicate that polyoxyethylene stearates effect efflux pumps (Lo 2003). Similar results were gained when using polyoxyethylene laurylether (Brij 30). In another study, tablets based on polyoxyethylene 40 stearate containing the P-gp substrate rhodamine 123 increased the oral bioavailability in rats by about 2.4-fold (Foger et al. 2006a). 

Mechano—chemical processes that are essential for HDPE macromolecular dispersion were defined by analyzing MWD of the transfer fragments of polyolefine—based composites doped with active additives (5 wt.%), such as antioxidant (Neozone D), aromatic compound (anthracene) and metal seilt (zinc stearate). Effect of the active additives on molecular features and certain friction characteristics of HDPE (load 0.5 MPa sliding velocity = 0.25 m/s) is shown in Table II. 

Plan, V., Le Hen-Ferrenbach, C., Beuchd, M. and Roussel, M. (flMS) New Sucrose Poly stearate Effective Emulsifier Combining Skin Touch with Moisturizing Properties, ISFCC Florence. 

The state of knowledge in the early 1990s of the effects of fat on health lacks clarity and general agreement. There is great support for the thesis that fully saturated fats are associated with problems of atherosclerosis and arterial fatty deposit, but there is evidence that stearates, which are saturates, are only poorly utilized in human digestion. Another body of work has estabUshed a connection between unsaturated fatty acids and a better state of arterial health and lowered fat body attachment to the arterial wall (23) contrary evidence exists that highly unsaturated fats polymerize more readily and thus contribute to arterial plaque formation. 

Inorganic salts are also used to promote shampoo thickening. These should be used sparingly since an excess may have a deleterious effect on a product s physical stabiHty. Sodium chloride commonly is used in these cases. The additions of sodium stearate and stearic amides can be found in paste shampoos for thickening. 

Ultimately, as the stabilization reactions continue, the metallic salts or soaps are depleted and the by-product metal chlorides result. These metal chlorides are potential Lewis acid catalysts and can greatiy accelerate the undesired dehydrochlorination of PVC. Both zinc chloride and cadmium chloride are particularly strong Lewis acids compared to the weakly acidic organotin chlorides and lead chlorides. This significant complication is effectively dealt with in commercial practice by the co-addition of alkaline-earth soaps or salts, such as calcium stearate or barium stearate, ie, by the use of mixed metal stabilizers. 

Dry lubricants are usually added to the powder in order to decrease the friction effects. The more common lubricants include zinc stearate [557-05-17, lithium stearate [4485-12-5] calcium stearate [1592-23-0] stearic acid [57-11-4] paraffin, graphite, and molybdenum disulfide [1317-33-5]. Lubricants are generally added to the powder in a dry state in amounts of 0.25—1.0 wt % of the metal powder. Some lubricants are added by drying and screening a slurry of powder and lubricant. In some instances, lubricants are appHed in Hquid form to the die wall. 

The 40% aqueous solution of TRIS AMINO is nonirritating to the eyes and skin. In general, the toxicology of the alkan olamines is typical of alkaline materials, ie, the greater the base strength, the greater the effect. Neutralized alkan olamines are much less toxic their stearate soaps, for instance, have been found to be nonhazardous. 

Accelerated sulphur systems also require the use of an activator comprising a metal oxide, usually zinc oxide, and a fatty acid, commonly stearic acid. For some purposes, for example where a high degree of transparency is required, the activator may be a fatty acid salt such as zinc stearate. Thus a basic curing system has four components sulphur vulcanising agent, accelerator (sometimes combinations of accelerators), metal oxide and fatty acid. In addition, in order to improve the resistance to scorching, a prevulcanisation inhibitor such as A -cyclohexylthiophthalimide may be incorporated without adverse effects on either cure rate or physical properties. 

Normal and dibasic lead stearate have a stabilising effect but their main uses are as lubricants (see section 12.5.4). Lead silicate is sometimes used in leathercloth formulations but is today of little importance. Other lead compounds now of negligible importance are coprecipitated lead orthosilicates and lead salicylate. 

Lucie, S., Kovacevic, V., Packham, D.E., Bogner, A., Gerzina, A., Stearate-modified calcium carbonate fillers and their effect on the properties of polyvinyl acetate, composites. Proc. 2nd Int. Symp. Polymer Surface Modification Relevance to Adhesion, Newark, NJ, 24-26 May, 1999. 

The layers in the plate-like structure of talc are Joined by very weak van der Waals forces, and therefore delamination at low shear stress is produced. The plate-like structure provides high resistivity, and low gas permeability to talc-filled polymers. Furthermore, talc has several other structure-related unique properties low abrasiveness, lubricating effect, and hydrophobic character. Hydrophobicity can be increased by surface coating with zinc stearate. 

This chapter reports the results of studies on the physical, dynamic mechanical, and rheological behavior of zinc oxide neutralized m-EPDM, particularly in the presence of stearic acid and zinc stearate, with special reference to the effects of precipitated silica filler. 

Since the system is processed as thermoplastics are processed, its reprocessability was studied under repeated cycles of extrusion in the MPT. Results of reprocessability studies are shown in Table 5. It is evident that after the first cycle viscosity increased slightly, which may be due to the orientation effect. In the subsequent cycles viscosity remained almost constant. Therefore, it is concluded that the zinc stearate plasticized zinc salt of m-EPDM is melt processable just as thermoplastics. 

Sodium bicarbonate, 112-113 Sodium carbonate, 61 Sodium chloride 44q common ion effect and, 439 electrolysis, 499 formation, 3 structure, 36 Sodium chlorine, 4 Sodium hydroxide, 61,84,441 Sodium hypochlorite, 369-370 Sodium stearate, 595 Sodium vapor lamps, 135 Solids... 

Comparative tests performed on a Ro-Tap unit, a vibrating unit (Sonic Sifter — Allen-Bradley), and the Alpine Air Jet Sieve are shown in Figs 6 and 7. Fig 6 is a powdered cement Fig 7 is cadmium stearate, a waxlike material which clogs easily. These separations were all made on a 42 micron mesh sieve. These tests showed that the Alpine Jet Sieve effected good separations in a matter of minutes compared with the much longer times required for the other systems... 

The surfactant ammonium xylenesulfonate is used as both a thickener and a hydrotrope, a compound that makes it easier for water to dissolve other molecules. It helps keep other ingredients in solution, including some of the odd substances that are added for marketing effect, such as perfumes. Glycerol stearate is another emulsifier used for this purpose. 

Solvent wiping. Rubbers tend to swell by application of solvents and the mechanical interlocking of the adhesive is favored. Although chlorinated hydrocarbon solvents are the most effective, they are toxic and cannot be used toluene and ketones are currently the most common solvents. The treatment with solvents is effective in the removal of processing oils and plasticizers in vulcanized mbbers, but zinc stearate is not completely removed and antiozonant wax gradually migrates to the mbber/polyurethane adhesive interface. Table 27.1 shows the moderate increase in adhesion produced in SBR by MEK wiping. 

Solutions of different carboxylic acids (fiimaric acid [FA], maleic acid, acrylic acid, succinic acid, and malonic acid) in ethanol have been effectively used as primers to increase the adhesion of synthetic vulcanized SBRs. The increase in the adhesion properties of SBR treated with carboxylic acid is attributed to the elimination of zinc stearate moieties and the deposition of acid on the rubber which migrates into the solvent-borne polyurethane adhesive layer once the adhesive joint is formed. The nature of the carboxylic acid determines the rate of diffusion into the adhesive and the extent of rubber-adhesive interfacial interaction. 

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