Salt-dependent viscosity

Trotter, J. A., Salgado, J. P., and Koob, T. J. (1997). Mineral content and salt-dependent viscosity in the dermis of the sea cucumber Cucumaria frondosa. Comp. Biochem. Physiol. 116A, 329-335. 

The dependence of our flow-resistance anomalies for HPAA upon salt concentration (Figure 24), is strikingly similar to the salt dependence of pore-flow viscosity enhancement (Figure 18). The critical onset strain rate from our experiments varies in the same way as the critical onset Reynolds number in pore flow. In both experiments no further dependence on salt concentration is observed beyond 0.5 M. Further, in pure water, both experiments show non-Newtonian behavior (in our case identifiable as flare) even at the lowest flow rates. 

Because protein-ba sed foams depend upon the intrinsic molecular properties (extent and nature of protein-protein interactions) of the protein, foaming properties (formation and stabilization) can vary immensely between different proteins. The intrinsic properties of the protein together with extrinsic factors (temperature, pH, salts, and viscosity of the continuous phase) determine the physical stability of the film. Films with enhanced mechanical strength (greater protein-protein interactions), and better rheological and viscoelastic properties (flexible residual tertiary structure) are more stable (12,15), and this is reflected in more stable foams/emulsions (14,33). Such films have better viscoelastic properties (dilatational modulus) ( ) and can adapt to physical perturbations without rupture. This is illustrated by -lactoglobulin which forms strong viscous films while casein films show limited viscosity due to diminished protein-protein (electrostatic) interactions and lack of bulky structure (steric effects) which apparently improves interactions at the interface (7,13 19). 

As shown in Fig. 4.6, the melting point of various hthium salts depends on the size of counter anions like the viscosity of the ILs as shown in Fig. 4.4. In the figure, the results for [BFsRp] were omitted due to their low decomposition temperature (ca. 150 °C) [58]. It was quite interesting that both the melting point and viscosity have the same tendency toward the size of the anion. The Li[fTfN] can be used as a onium-free lithium single molten salt from 100 °C to the decomposition temperature (300 °C) [57]. Such an onium-free lithium single salt will be useful to focus on... 

The ionic-strength dependence of the elution of CMC was studied by Barth and Regnier (51) on glycerylpropylsilyl derivatized LiChrospher. No explicit attempt was made to separate polyion expansion effects from polyion-substrate interaction. However, one could note that the salt-dependence of the intrinsic viscosity essentially vanished at I > 0.1, whereas Ksec continued to decrease in the range 0.1 < I < 0.5. This rather qualitative observation suggests that polyion-substrate repulsion persists even for derivatized silica. 

The relevant temperatures being much lower than for the anhydrous molten salts, the viscosities of the molten salt hydrates are larger and the conductivities considerably smaller than for the anhydrous salts. No details of the temperature dependencies of // and A could be shown, however. 

Interestingly, the J values of the ions are nearly additive for a given salt. Although no convincing theory exists so far to explain the concentration dependence of salt solution viscosities, it seems plausible to attribute the B values to ion-water interactions. According to Collins, negative values can be related to soft ions with low surface density. Here, water-water... 

Polyamines can also be made by reaction of ethylene dichloride with amines (18). Products of this type are sometimes formed as by-products in the manufacture of amines. A third type of polyamine is polyethyleneimine [9002-98-6] which can be made by several routes the most frequently used method is the polymeriza tion of azitidine [151 -56 ] (18,26). The process can be adjusted to vary the amount of branching (see Imines, cyclic). Polyamines are considerably lower in molecular weight compared to acrylamide polymers, and therefore their solution viscosities are much lower. They are sold commercially as viscous solutions containing 1—20% polymer, and also any by-product salts from the polymerization reaction. The charge on polyamines depends on the pH of the medium. They can be quaternized to make their charge independent of pH (18). 

The viscosity of solutions is quite temperature dependent increasing the temperature leads to a reduction in viscosity, which approaches zero at approximately 60°C (322). The viscosity is relatively stable from pH 3—10 and is compatible with a number of inorganic salts other than sodium. The production of succinoglycan and its potential use in foods and industrial processes as a thickening agent has been described (322). 

Concentration and Molecular Weight Effects. The viscosity of aqueous solutions of poly(ethylene oxide) depends on the concentration of the polymer solute, the molecular weight, the solution temperature, concentration of dissolved inorganic salts, and the shear rate. Viscosity increases with concentration and this dependence becomes more pronounced with increasing molecular weight. This combined effect is shown in Figure 3, in which solution viscosity is presented as a function of concentration for various molecular weight polymers. 

Sihcate solutions of equivalent composition may exhibit different physical properties and chemical reactivities because of differences in the distributions of polymer sihcate species. This effect is keenly observed in commercial alkah sihcate solutions with compositions that he in the metastable region near the solubihty limit of amorphous sihca. Experimental studies have shown that the precipitation boundaries of sodium sihcate solutions expand as a function of time, depending on the concentration of metal salts (29,58). Apparently, the high viscosity of concentrated alkah sihcate solutions contributes to the slow approach to equihbrium. 

Gum-Saline. Gum is a galactoso—gluconic acid having molecular weight of approximately 1500. First used (16) in kidney perfusion experiments, gum—saline enjoyed great popularity as a plasma expander starting from the end of World War I. The aggregation state of gum depends on concentration, pH, salts, and temperature, and its coUoid oncotic pressure and viscosity are quite variable. Conditions were identified (17) under which the viscosity would be the same as that of whole blood. 

It turns out that in low-viscosity blending the acdual result does depend upon the measuring technique used to measure blend time. Two common techniques, wliich do not exhaust the possibilities in reported studies, are to use an acid-base indicator and inject an acid or base into the system that will result in a color change. One can also put a dye into the tank and measure the time for color to arrive at uniformity. Another system is to put in a conductivity probe and injecl a salt or other electrolyte into the system. With any given impeller type at constant power, the circulation time will increase with the D/T ratio of the impeller. Figure 18-18 shows that both circulation time and blend time decrease as D/T increases. The same is true for impeller speed. As impeller speed is increased with any impeller, blend time and circulation time are decreased (Fig. 18-19). 

As in die case of die diffusion properties, die viscous properties of die molten salts and slags, which play an important role in die movement of bulk phases, are also very stiiicture-seiisitive, and will be refeiTed to in specific examples. For example, die viscosity of liquid silicates are in die range 1-100 poise. The viscosities of molten metals are very similar from one metal to anodier, but die numerical value is usually in die range 1-10 centipoise. This range should be compared widi die familiar case of water at room temperature, which has a viscosity of one centipoise. An empirical relationship which has been proposed for die temperature dependence of die viscosity of liquids as an AiTlienius expression is... 

We recently prepared various types of differently fiuorinated alkyl sulfate ILs and discovered that the hydrophobicity was dependent on the content ratio of the fluorine on the alkyl sulfate anion and 2,2,3,3,4,4,5,5-octafiuoropentyl sulfate salts showed hydrophobic properties. Melting point and viscosity were also dependent on the fluorine contents of the anionic part, while conductivity was determined by the cationic part and not influenced by the fluorine contents. Efficient lipase-catalyzed transesterificafion was demonstrated using hydrophobic 1-butyl-3-methylimidazolium 2,2,3,3,4,4,5,5-octafiuoropentyl sulfate ([bmim][C5E8]) as solvent (Eig. 6). ... 

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