Viscosity concentration effect

Emulsions. Because emulsions are different from dispersions, different viscosity—concentration relationships must be used (71,87). In an emulsion the droplets are not rigid, and viscosity can vary over a wide range. Several equations have been proposed to account for this. An extension of the Einstein equation includes a factor that allows for the effect of variations in fluid circulation within the droplets and subsequent distortion of flow patterns (98,99). 

Decrease Binder Viscosity Lower temperature since binder concentration will decrease due to drying thereby lowering viscosity. This effect generally offset due to inverse relationship between viscosity and temperature. 

The ultimate success of methyl methacrylate bone cements in surgical arenas depends on its application at an appropriate viscosity. Recent studies have raised concerns that the long-term stability of bone cements may be compromised by the empirical way in which the setting of samples is determined [6]. The literature from one manufacturer states that, in addition to the concentration effects one would expect in a biphasic free-radical... 

The electroviscous effect can influence the results of viscosity determinations, but this can be avoided by using a sufficiently high concentration of salt12 when linear specific viscosity concentration versus concentration curves are obtained. Gelation effects with Fe++, Fe+++ and Cu++ ions also occur127 and so should be avoided. 

The viscosities of many binary liquid systems display minima as functions of composition at constant temperature, so that negative values of D are also possible. Yajnik and his coworkers (265 ) long ago observed that very frequently an extremum in the isothermal vapor pressure-composition curve is accompanied by an extremum of the opposite sense in the viscosity-concentration curve. Data are apparently not available for solutions of very low-molecular-weight paraffins in carbon tetrachloride, but minima are found for the viscosities of solutions of CC14 with ethyl iodide, ethyl acetate and acetone, so that a minimum appears quite probable for mixtures of small aliphatic hydrocarbons with carbon tetrachloride. If this were true, the downward trend of the Meyer-Van der Wyk data on C17—C31 paraffins, earlier discussed in connection with the polyethylene plots of Fig. 14, would be understood. It will be recognized that such a trend is also precisely what is to be expected from the draining effect of the hydrodynamic theories of Debye and Bueche (79), Brinkman (45 ) and Kirkwood and Riseman (139). However, the absence of such a trend in the case of polyethylene... 

Time Effect of Gegenion on Percent Conversion and Intrinsic Viscosity. The effect of gegenion on percent conversion to polymer and on intrinsic viscosity of the polymers is shown in Table V. Duplicates and runs with fresh catalyst solution all followed the same pattern. In the experiment using the BF4 gegenion at 10 times the usual concentration, the final conversion is increased considerably, although it still falls 2% below the equilibrium conversion. 

Two mechanisms will affect the ink drop once it hits the heated surface decrease of viscosity due to the higher temperature of the ink and evaporation of the volatile ink components, causing higher solid concentration in the ink and a fast increase in ink viscosity. It is necessary to heat the substrate to a high enough temperature to ensure the viscosity-increase mechanism is dominant, to enable the overall viscosity-increase effect. 

Organic photochemical reactions conducted in micellar solutions are reviewed from the standpoint of systematizing and correlating published results. Five common effects are found to distinguish and characterize micellar photochemistry relative to conventional solution photochemistry super cage effects, local concentration effects, viscosity effects, polarity effects, and electrostatic effects. These effects can contribute to the occurence of enhanced selectivity and efficiency of photoreactions relative to those in conventional homogeneous solution. 

Hred) is obtained by dividing by the concentration of the solution, C. Viscosity increases as the concentration increases. In order to eliminate the concentration effects, the specific viscosity is divided by concentration and extrapolated to zero concentration to give the intrinsic viscosity (or limiting viscosity number), [r/]. Viscosity determined at a single concentration, inherent viscosity (rjinh), extrapolates to the same [r/], and can also be used as an approximate indication of molecular weight (Fig. 14.18). 

Vitali, A. A. and Rao, M. A. 1984b. Flow properties of low-pulp concentrated orange juice Serum viscosity and effect of pulp content. J. Food Sci. 49 876-881. 

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