Peptizing effect

Cathodic protection is a useful supplement to other forms of water treatment, as a general corrosion inhibiting device in HW boilers, or where specific design configurations can lead to inadequately protected localized metal in steam boilers. Where BW makeup demands are minimal and boiler output is fairly constant, cathodic protection devices can also provide some measure of protection against hardness scales. Calcium carbonate salt is formed as a floc-culant or soft sludge rather than a hard scale, due to the peptizing effects of a zinc hydroxide complex formed from zinc ions in alkaline BW. 

Figure 4. Asphaltene particle peptization effected by adsorbed resin molecules. This physical model is the basis of our asphaltene Thermodynamic-Colloidal Model.

Selby In the sense that there is little hydrolytic action going on, I consider it purely as a peptization effect. ... 

The formation of the sol can be a critical part of the process. While boehmite and the amorphous hydroxide prepared by cold water hydrolysis can be peptized to a clear sol, bayerite will not form a sol and its formation during hydrolysis should therefore be avoided. In addition, the nature of the acid has a significant effect on the peptization step. Table 5.8 shows the peptizing effect of various acids on the precipitate formed by hydrolysis of aluminum s ec-butoxide. The results are similar when aluminum isopropoxide is used. It appears that only strong or fairly strong acids, which do not form chemical complexes (or form only very weak complexes) with aluminum ions, are effective for achieving peptization. For these acids, the concentration of the acid also has an effect. Peptization... 

Table 5.8 Peptizing Effect of Various Acids on the Precipitate Formed by the Hydrolysis of Aluminum icc-Butoxide...

The liquid PEG grades mainly used for the production of cellulose films have the following valuable properties as humectants or plasticizers balanced hygroscopic-ity complete nonvolatility, absolute transparency, peptizing effect on resin components of the viscose, anchoring effect on nitrocellulose lacquers, and the imparting of dimensional stability. 

Chem. Descrip. Zinc salts of higher molecular fatly acids Uses Peptizing agent and dispersant for lire compds., molded, extruded, and hard rubber vulcanization accelerator peptizing effect in NR and IRfrom 60 C retards scorch processing promoter for elastomers and compds., esp. NR Properties LI. bm. pellets sp.gr. 1.08 Aktiplast ST [Rhein Chemie]... 

Monomer conversion (79) is followed by measuring the specific gravity of the emulsion. The polymerization is stopped at 91% conversion (sp gr 1.069) by adding a xylene solution of tetraethylthiuram disulfide. The emulsion is cooled to 20°C and aged at this temperature for about 8 hours to peptize the polymer. During this process, the disulfide reacts with and cleaves polysulfide chain segments. Thiuram disulfide also serves to retard formation of gel polymer in the finished dry product. After aging, the alkaline latex is acidified to pH 5.5—5.8 with 10% acetic acid. This effectively stops the peptization reaction and neutralizes the rosin soap (80). 

Detergents act as emulsifiers, breaking the oil into tiny droplets, each suspended in water. The disruption of the oil film allows the dirt particles to become solubilized (they peptize). Soap, the sodium or potassium salt of long-chain fatty acids, is a good detergent, although it often forms insoluble compounds with certain salts found in hard water, thus diminishing its effectiveness. 

The fact that plasticization of rubber in the mixing mill is the result of oxidation implies that oxygen is indispensable for the same. Agents which accelerate oxidation thereby effecting plasticization to a desired mooney viscosity level are called peptizing agents. 

One way in which we can tell that we are dealing with a reversible coagulation of nerve proteins is that a substance which peptizes proteins must counteract to some extent the effect of any drug which produces... 

As an instance of the latter we may take potassium iodide which is used to some extent medicinally. Since it peptizes gelatin and albumin very strongly, one would expect it to counteract morphine or chloroform to some extent. On the other hand the iodide may have distinctly harmful effects as has been pointed out by Dr. Keith.6... 

It seemed wise, therefore, to make preliminary experiments with sodium thiocyanate, NaCNS, because the sodium ion is not especially toxic and the thiocyanate ion is very effective in causing the peptization of proteins. The difference in action between sodium and potassium thiocyanate is apparently very great. We have injected 30 cc. of a 20% sodium thio-... 

Peptization also occurs naturally, such as when flowing water acts to convert unconsolidated particulate rock material into colloidal suspensions [49]. In this case peptization can be due to both the dilution effect and also to ion exchange reactions (such as the exchange of coagulating calcium ions for peptizing sodium ions). 

Washing the precipitates It is essential to wash all precipitates in order to remove the small amount of solution present in the precipitate, otherwise it will be contaminated with the ions present in the centrifugate. It is best to wash the precipitate at least twice, and to combine the first washing with the centrifugate. The wash liquid is a solvent which does not dissolve the precipitate but dilutes the quantity of mother liquor adhering to it. The wash liquid is usually water, but may be water containing a small amount of the precipitant (common ion effect) or a dilute solution of an electrolyte (such as an ammonium salt) since water sometimes tends to produce colloidal solutions, i.e. to peptize the precipitate. 

---