Stabilizing agents bentonite

Several stabilization agents are available, ie, protolytic enzymes, tannic acid, or various adsorbents such as polyvinylpyrroHdinone (PvPP) and nylon-6,6 or bentonite. The stabilizing agent is normally added during the transfer to the stabilizing tank and left for some hours to react. 

However, the mechanism of action of filtration control additives is not yet completely understood. Examples are bentonite, latex, various organic polymers, and copolymers. Many additives for fluid loss are water-soluble polymers. Vinyl sulfonate fluid loss additives based on the 2-acrylamido-2-methyl-propane sulfonic acid (AMPS) monomer are in common use in field cementing operations [363]. The copolymerization of AMPS with conjugate monomers yields a fluid loss agent whose properties include minimal retardation, salt tolerance, high efficiency, thermal stability, and excellent solids support. 

Thickeners and binders such as acacia, agar, starch, sodium alig-nate, gelatin, methyl cellulose, bentonite, and silica are used to improve product stability and enhance the convenience of the administration of a liquid formulation. Surface-active agents, colors, flavors and preservatives may also be used in the final formulation (Garcia et ah. Bioseparation Process Science, Blackwell Science, Malden, Mass., 1999, p. 374). 

The viscosity of an emulsion can be of crucial importance for its stability, especially the viscosity of the external phase. A high viscosity reduces creaming and also lessens the tendency of particles to coalescence and produce phase separation. Examples of the widely used viscosity-imparting agents are alginates, bentonite, carboxymethylcellulose, polyvinyl pyrrolidone, hydroxypropylcellulose, and carbomer. 

Achiral, C -symmetric unbridged metallocenes, 16 104 Achiral hydrobora ting agents, 13 667 Achiral molecules, 6 73 Acicular reinforcement, 5 554 Acid acceptors, in VDC polymer stabilization, 25 719 Acid-activated bentonites, 6 680-681 Acid amide herbicides, 13 319-320 Acid anhydrides, 10 403-406, 484 reactions with alkanolamines from olefin oxides and ammonia, 2 127 Acid-base catalysis, 5 205-209... 

Efforts should be made to stabilize an enzyme s activity. Certain agents (such as glycerol, ammonium ions, boric acid, polyethylene glycol, and even talcum powder or bentonite clay) have proven widely to be effective enzyme stabilizers. For multisubstrate enzymes, inclusion of one particular substrate with the enzyme (in the absence of other substrates or cofactors) often stabilizes an enzyme s catalytic activity. Such a substrate may also assist in unlocking the enzyme from a particularly inactive conformational form. In addition to substrates, other ligands and effectors (including reaction products. 

Several treatment agents of wine yeast cell walls, sodium caseinate, gelatin, bentonite were evaluated for their potential to bind with aroma compounds. The loss of sensory properties of wine, especially flavor modification, is partly caused by protein stabilization treatments with fining agents or ultrafiltration processing of wine (IS 14). Yeast cell walls are used in sluggish or stuck wine fermentation the effect on fermentation has been explained by the adsorption of toxic fatty acids present in the growth medium (15). Therefore yeast walls are also assumed to bind aroma compounds. 

Specific additives and minors Corrosion inhibitors (sodium silicate) Foam boosters (alkylolamides) Foam inhibitors (hydr. soap/silic. oils) Stabilizers/sequestrants Optical brighteners/fluorescent whitening agents Soil antiredepositioning agents (CMC, Bentonite) Enzymes (alcalase, protease) Minors (dyestuffs, perfume)... 

Bentonite has a negative charge that fixes the positive unstable colloids and pulls them down. It is more efficient than cold flocculation of the colloids. The problem is different in the case of protein-based fining agents. Some of the colloids are pnlled down by the flakes of tannin-protein complexes, while the rest are stabilized by residnal proteins that are also part of the wine s colloidal strnctnre. 

Fillers (calcium carbonate, calcium sulfate, aluminum oxide, bentonites, wood flour) increase the solid content of the dispersion, and they are added up to 50%, based on PVAc. The purpose of their addition is the reduction of the penetration depth, a thixotropic behavior of the adhesive, gap filling properties, and the reduction of the adhesive costs. Disadvantages can be the increase of the white point and possibly the more marked tool wear rate due to greater hardness of the adhesive. Other components in PVAc formulations are defoamers, stabilizers, filler dispersants, preservatives, thickeners (hydro-xyethylcellulose, carboxymethylcellulose), poly(vinyl alcohols), starch, wetting agents, tackifiers, solvents (alcohols, ketones, esters), flame retardants, and others. 

Chem. Descrip. Unsat. polyamide and acid ester salts Uses Wetting agent/dispersant for pigments/organically treated bentonites in solv. or solv.-free coatings Features Solv.-free shorfer disp. fime improved storage stability Properties Dk. brn. liq. dens. 0.98-1.02 g/cm cid no. 58-72 amine no. 10-30 anionic/cationic 100% act. 

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