Mineral stability

In the pharmaceutical field, agar is commonly the base colloid for stabilizing mineral oil in water emulsions, used for laxative purposes. The concentration of agar is kept below the gel point, so that the emulsion will pour. Other gums, like tragacanth, Irish moss extract, or carboxymethylcellulose, may replace the agar, where desired. Usually, from 0.5 to 0.8% of the gum, based upon the weight of the aqueous phase, suffices to protect this type of emulsion, which is somewhat of a neutral variety. 

Fong-Spaven, F., and Hollenbeck, R. G. (1986), Thermal rheological analysis of triethanolamine-stearate stabilized mineral oil in water emulsions, Drug Dev. Ind. Pharm., 12, 289. 

Because of the effect of particle size on relative stabilities, minerals such as lepidocrocite and goethite (Run 4) or goethite and hematite may reverse in stability. 

Potyacryttc acid stabilizer, mineral oils Rhodasutf ON-870 stabilizer, mineral-filled PP Ultranox 626 stabilizer, monomer Phenothlazine... 

Carrageenan (Chondrus crispus) stabilizer, mineral processing Nonoxynol-7 stabilizer, mining... 

A typical gun-grade acrylic emulsion sealant (Table 15) contains about 18% acrylic polymer solids and 9-10% of a polymeric plasticizer. Sodium polymetaphosphate is a primary pigment dispersant aided by a water-soluble polyacrylate. A nonionic surfactant acts as a wetting agent and emulsifier. Often small amounts (up to 2%) of glycols are included for additional freeze-thaw stability. Mineral spirits (about 2%) retards skin formation. Acrylic emulsion caulks are used indoors as bathtub caulks, baseboard and trim seams, and outdoors for glazing, masonry joints, and roof and siding joints. 

Figure 5.4 Apparent shear viscosity as a function of shear stress for fine surfactant-stabilized mineral oil-in-water emulsions (d 2 = 0.55 pm, 0.05 M phosphate buffer, pH 7) as determined at 25 C in a controlled stress rheometer (filled symbols) and a controlled strain-rate rheometer (open symbols) , O, 30 wt% oil, I wt% Tween 20 A, A, 40 wt% oil, 1.33 wt% Tween 20 , O, 50wt% oil, 1.67 wt% Tween 20 , Q 60 wt% oil, 2 wt% Tween 20...

Comments GF = glass fibre. MF LS = light stabilized = mineral addition. Also available PBTB130F (30% GF) and PBTB820F (20% GF VO), ... 

They are prepared by the action of HNO2 on aromatic amines. The amine is dissolved in excess of mineral acid and sodium nitrite is added slowly until a slight excess of HNO2 is present. The reaction is usually carried out in ice-cold solution. The solution then contains the diazonium salt of the mineral acid used, anhydrous diazonium salts of unpredictable stability may be precipitated with complex anions like PF , SnCl6 BF4 . 

Figure 5.12 Relative chemical stability of carbonate minerals...

The importance of the thin film between the mineral particle and the air bubble has been discussed in a review by Pugh and Manev [74]. In this paper, modem studies of thin films via SFA and interferometry are discussed. These film effects come into play in the stability of foams and froths. Johansson and Pugh have studied the stability of a froth with particles. Small (30-/ m), moderately hydrophobic 6c = 65°) quartz particles stabilized a froth, while more hydrophobic particles destabilized it and larger particles had less influence [75]. 

Hydrotalcite. Synthetic hydrotalcite minerals are gaining commercial acceptance for thein abiHty to costabiHze PVC ia the presence of other primary stabilizers (see Table 2). The performance of the mixed metal stabilizers are particularly boosted when an equal part level, about 2—3 phr, of hydrotalcite is added to the PVC formulation. These minerals function by trapping HCl within the layered lattice arrangement of atoms. The formula. 

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