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Viscosity of dilute

Viscosity—Concentration Relationship for Dilute Dispersions. The viscosities of dilute dispersions have received considerable theoretical and experimental treatment, partly because of the similarity between polymer solutions and small particle dispersions at low concentration. Nondeformable spherical particles are usually assumed in the cases of molecules and particles. The key viscosity quantity for dispersions is the relative viscosity or viscosity ratio,... [Pg.173]

For commercial purposes the molecular weight is usually characterised from measurements of the viscosity of dilute solutions. It has been shown that, for dilute solutions, the relation between the viscosity and the molecular weight (in this case the viscosity average molecular weight) may be given by the relationship... [Pg.320]

Huggins M.L. The Viscosity of Dilute Solutions of Long-Chain Molecules. IV. Dependence on Concentration. J. Am. Chem. Soc., 64,11 (1942) 2716-2718. [Pg.113]

This is the same as the expression for the viscosity of dilute suspensions (see for example Chapter 3). The expression is however limited to low concentrations of particles, i.e. for tp < 0.05 there are others that can be used throughout the range of volume fractions. Landel26 proposed that the elastic modulus can be described by... [Pg.45]

In Chapter 3 (Section 3.5.2) the viscosity of a hard sphere model system was developed as a function of concentration. It was developed using an exact hydrodynamic solution developed by Einstein for the viscosity of dilute colloidal hard spheres dispersed in a solvent with a viscosity rj0. By using a mean field argument it is possible to show that the viscosity of a dispersion of hard spheres is given by... [Pg.230]

We will now turn our attention from the viscosity of dilute solutions and look at the viscosity of melted polymers. The viscosity of melted polymers is important in transferring resins and in polymer processing such as determining the correct conditions to have a specific flow rate for injection processing and in determining the optimum conditions to get the necessary dimensions of extruded shapes. Fillers, plasticizers, temperature, solvents, and molecular weight are just some of the variables that influence the viscosity of polymer melts. Here we will look at the dependence of melt viscosity on polymer molecular weight. Polymer melts have viscosities on the order of 10,000 MPa (1 centipoise =0.001 Pa/sec). [Pg.77]

Huggins, M.L. 1942. The viscosity of dilute solutions of long-chain molecules. IV. Dependence on concentration. J. Amer. Chem. Soc., 64 2716. [Pg.82]

The properties of solutions of macromolecular substances depend on the solvent, the temperature, and the molecular weight of the chain molecules. Hence, the (average) molecular weight of polymers can be determined by measuring the solution properties such as the viscosity of dilute solutions. However, prior to this, some details have to be known about the solubility of the polymer to be analyzed. When the solubility of a polymer has to be determined, it is important to realize that macromolecules often show behavioral extremes they may be either infinitely soluble in a solvent, completely insoluble, or only swellable to a well-defined extent. Saturated solutions in contact with a nonswollen solid phase, as is normally observed with low-molecular-weight compounds, do not occur in the case of polymeric materials. The suitability of a solvent for a specific polymer, therefore, cannot be quantified in terms of a classic saturated solution. It is much better expressed in terms of the amount of a precipitant that must be added to the polymer solution to initiate precipitation (cloud point). A more exact measure for the quality of a solvent is the second virial coefficient of the osmotic pressure determined for the corresponding solution, or the viscosity numbers in different solvents. [Pg.16]

Composition Dependence of Alloy Viscosity. Attempts have been made to calcnlate the viscosity of a dilnte liquid alloy from a theoretical standpoint, but with little success. This is primarily due to the fact that little is known about the interaction of dissimilar atoms in the liquid state. Empirical relationships for the viscosity of dilute liquid alloys have been developed, but these are generally limited to specific alloy systems—for example, mercury alloys with less than 1% impurities. The viscosities of binary liquid alloys have been empirically described using a quantity called the excess viscosity, (not to be confused with the excess chemical potential), which is defined as the difference between the viscosity of the binary mixture (alloy), pa, and the weighted contributions of each component, xipi and X2P2-... [Pg.290]

Viscosity of Dilute Solutions of Salts in Mixed Solvents... [Pg.335]

Pao,Y.-H. Dependence of intrinsic viscosity of dilute solutions of macromolecules on velocity gradient. J. Chem. Phys. 25,1294-1295 (1956). [Pg.176]

Viscosity Measurements. Although in typical polymer-plasticizer systems, the polymer is the major component, it is possible to use the viscosity of dilute polymer solutions as a measure of the solvent power of the liquid for the polymer. Thus, liquids with high solvent power for the polymer cause a stretching out of the chain molecules, whereas a liquid of poor solvent power causes the chains to coil up. This is because, in the liquid with poor solvent power, the segments of the polymer chain (the monomer units) prefer to stay close to each other, while in a good solvent, interaction between polymer segments and solvent molecules is preferred. [Pg.19]

The DTO model ignores the overall translations and rotations of the molecule as a whole and refers only to internal vibrational modes. It is therefore incapable of explaining on its own the viscosity of dilute polymer solutions. The enhanced viscosity of dilute polymer solutions is undoubtedly due to a hydrodynamic damping of the polymer as a whole as it translates and rotates in the shear field. This was very well described by Debye (21). We should point out that the Debye viscosity is alternatively derivable from the RB theory. [Pg.125]

Considering the development of the theory of melt viscosity, one notices a similar kind of evolution as with the intrinsic viscosity of dilute solutions. In both cases starting points were formed by empirical relations describing the respective molecular weight dependencies. Only afterwards, the relations are interpreted on more fundamental grounds. [Pg.244]

Gundert F, Wolf BA (1986) Viscosity of dilute polymer solutions molecular weight dependence of the Huggins coefficient Makromol Chem 187 2969... [Pg.160]

The degradation of pectin irradiated under various conditions of moisture has also been studied (30). Changes in intrinsic viscosity of dilute pectin solutions were used as a measure of the degree of degradation. Pec-... [Pg.9]

Bawn, C. E. H. High polymer solutions. Part V. Effect of concentration on the viscosity of dilute solutions. Trans. Faraday Soc. 47, 97 (1951). [Pg.571]

Huggins, M. L. The viscosity of dilute solutions of long-chain molecules. [Pg.573]

For convenience, this chapter has been divided into three sections in which the viscosity of dilute solutions and dispersions, non-Newtonian flow, and the viscoelastic properties of semi-solid systems are discussed. [Pg.245]

Viscosities of dilute colloidal solutions and dispersions Functions of viscosity... [Pg.249]

Cooke BJ, Matheson AJ (1976) Dynamic viscosity of dilute polymer solutions at high frequencies of alternating shear stress. J Chem Soc Faraday Trans II 72(3) 679-685 Curtiss CF, Bird RB (1981a) A kinetic theory for polymer melts. I The equation for the single-link orientational distribution function. J Chem Phys 74 2016—2025 Curtiss CF, Bird RB (1981b) A kinetic theory for polymer melts. II The stress tensor and the rheological equation of state. J Chem Phys 74(3) 2026—2033 Daoud M, de Gennes PG (1979) Some remarks on the dynamics of polymer melts. J Polym Sci Polym Phys Ed 17 1971-1981... [Pg.242]

Kalashnikov VN (1994) Shear-rate dependent viscosity of dilute polymer solutions. J Rheol... [Pg.245]

Elfak, A. M., Pass, G., Phillips, G. O., and Morley, R. G. (1977). The viscosity of dilute soludons of guar and locust bean gum with and without added sugars. J. Sci. Food. Agric. 28 895-899. [Pg.200]

The viscosity of dilute polymer solutions can be estimated with fair accuracy. [Pg.599]

In order to overcome this difficulty, Rudin and Strathdee (1974) developed a semi empirical method for predicting the viscosity of dilute polymer solutions. The method is based on an empirical equation proposed by Ford (1960) for the viscosity of a suspension of solid spheres ... [Pg.602]

Rudin and Strathdee (1974) remarked that the equations presented for the viscosity of dilute polymer solutions were valid approximately up to the critical concentration. This leads to a more general definition of a concentrated polymer solution, viz. a solution for which c > ccr. [Pg.605]

Moore, W. R., Murphy, M., Viscosities of Dilute Solutions of Polyvinyl... [Pg.335]

The majority of theories describing the concentration dependence of viscosity of diluted and moderately concentrated disperse systems is based on the hydrodynamic approach developed by Einstein [1]. Those theories were fairly thoroughly analyzed in the reviews written by Frish and Simha [28] and by Happel and Brenner [29], In a fairly large number of works describing the dependence of viscosity on concentration the final formulas are given in the form of a power series of the volume concentration of disperse phase particles — [Pg.111]


See other pages where Viscosity of dilute is mentioned: [Pg.81]    [Pg.171]    [Pg.309]    [Pg.635]    [Pg.165]    [Pg.171]    [Pg.336]    [Pg.338]    [Pg.340]    [Pg.342]    [Pg.344]    [Pg.47]    [Pg.290]    [Pg.200]    [Pg.243]    [Pg.100]    [Pg.197]    [Pg.767]   
See also in sourсe #XX -- [ Pg.294 ]

See also in sourсe #XX -- [ Pg.294 ]




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