Thickening solution

Disperse Dyes. Disperse dyes are used in powder or paste form, or ready-to-prepare aqueous dispersions for incorporation into a thickener solution. Eor disperse dyes that show sensitivity to alkaline hydrolysis or reduction during fixation, an acid donor or acid, and, if necessary, a mild oxidizing agent, are added to the print paste. 

Thickened solutions of caustic are used as oven and grill cleaners. 

Disperse Dyes. Disperse dyes are used in powder or pasted fonn. or ready-to-prepare aqueous dispersions for incorporation into a thickener solution. 

Figure 5. The effect of nonionic surfactant, Tergitol 15-S-9, on the viscosity of the associative thickener solutions. Key A, 4% HEUR 100 O, 4% HEUR 200 O, 4% HEUR 708 0, 2% HEUR 270.

Syneresis. This chapter began with consideration of the depletion layer effect. This phenomenon can be seen in coatings that contain large latices (>300 nm) not highly stabilized by surface-attached (hydroxy-ethyl)cellulose fragments (16), and is in part the problem observed in the last sections of Chapter 27. The phenomenon is not necessarily restricted to HEC-thickened formulations and depletion flocculation. In our studies, syneresis is observed in thickened aqueous solutions and in dispersed systems containing the model trimer associative thickener (Scheme II) it can be overcome by addition of conventional surfactants. Syneresis in HMHEC-thickened solutions is discussed in Chapter 19 in the absence of a dispersed phase. Syneresis is discussed in the following chapter where additives that substantially enhance low shear viscosities are added to inhibit syneresis. 

Xanthan gum will dissolve in acids such as 5% acetic acid and remain stable for several months unless the temperature is elevated. Also, xanthan gum is soluble directly in 5% sodium hydroxide solutions. Sodium hydroxide solutions of 0-15% can be thickened, provided the gum is pre-dissolved in water prior to adding the sodium hydroxide solution. These highly alkaline, thickened solutions have exceptional viscosity stability. Water miscible compounds such as ethanol are compatible with xanthan gum solutions up to concentrations of 50%. Solutions, emulsions, and gels that contain xanthan gum have excellent freeze-thaw resistance and many applications in the food industry. 

B. Degradation Tests. Thickened solutions for mechanical degradation were prepared to 37.0-40.0 Pa s viscosities (t - 12s ), and exposed to mechanical stresses in a Waring blendor ( 4 speed). Water (lO C) was passed through an exterior jacket to minimize heat buildup in the liquid under deformation. 

The rheological properties of hydrophobe-modified alkali-swellable emulsion (HASE) thickener solution are studied, with emphasis on surfactant and electrolyte (NaCl) effect. Similar studies in model HASE thickeners have been reported. Two commercial HASE thickeners (HASE-615 and HASE-935) are examined for comparison. In the absence of SDS, the NaCl addition changes solution viscosity depending on the relative concentration of the NaCl and thickener. The viscosities of HASE type thickeners are enhanced by an anionic surfactant, sodium dodecyl sulphate (SDS) and viscosity maxima are observed due to mixed micelle formation among thickener hydrophobes and surfactants. The addition of NaCl suppresses the viscosity of HASE-615/ SDS solutions, with HASE-935 at higher concentrations actually increasing in viscosity with NaCl addition. 2 refs. USA... 

The quaternary bis-hexaminium salt described here is particularly useful as a preservative in a wide variety of water based systems, e.g. polymer emulsions, latex paints, pigment and dye slurries, concrete additives, starches, thickener solutions. Addition rates 0 05-0-2%. For the rest what is mentioned before under Section 3.3 and 3.3.2 is valid. 

The numbers of living cells in water can be sufficiently reduced by the addition of 1% of a 3% hydrogen peroxide solution. Heavily contaminated products, e.g. water based paints and thickener solutions showing signs of viscosity loss due to enzymatic degradation may be saved by the addition of 0 05-0 1% of a 30% hydrogen peroxide solution with stirring. After 24 h, when microbes and enzymes are inactivated and most of the unpleasant odours are eliminated by oxidation, the viscosity of the material is restored with additional thickener and the in-can/ in-tank protection by the incorporation of a suitable preservative. 

In-tank/in-can protection of aqueous functional fluids, e.g. polymer emulsions, water based paints and adhesives, glues, starch slurries, thickener solutions, gelatine, wax emulsions, inks, polishes, pigment and mineral slurries, rubber latexes, concrete additives, drilling muds, aqueous cosmetic and pharmaceutical formulations. 

Multiple-Particle Tracking (MPT) Measurements of Heterogeneities in Acrylic Thickener Solutions... 

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