Viscosity treatment

Theory presented earlier in this chapter led to the expectation that the frictional coefficient /o for a polymer molecule at infinite dilution should be proportional to its linear dimension. This result, embodied in Eq. (18) where P is regarded as a universal parameter which is the analog of of the viscosity treatment, is reminiscent of Stokes law for spheres. Recasting this equation by analogy with the formulation of Eqs. (26) and (27) for the intrinsic viscosity, we obtain ... 

The kinetic theory derivation of the thermal conductivity coefficient is very similar in spirit to the viscosity treatment just discussed. In the schematic shown in Fig. 12.2, we considered a fluid between two plates held at different temperatures. At steady state the fluid temperature varies linearly across the channel, and heat flows from the top, higher-temperature... 

Thus, when a particle jumps, it leaves behind a hole. So then, instead of saying that a transport process occurs by particles hopping along, one could equally well say that the transport processes occur by holes moving. The concept is commonplace in semiconductor theory, where the movement of electrons in the conduction band is taken as being equivalent to a movement of so-called holes in the valence band. It has in fact already been assumed at the start of the viscosity treatment (Section 5.7.1) that the viscous flow of fused salts can be discussed in terms of the momentum transferred between liquid layers by moving holes. 

In this review we have briefly discussed the theoretical and experimental aspects of both Newtonian and non-Newtonian viscosities of polymer solutions. To protein chemists one of the interesting developments is no doubt the re-examination of the (Newtonian) viscosity treatments of protein solutions. There are many assumptions involved in the effective use of intrinsic viscosity measurements for evaluating the asymmetry of the protein molecules, however attractive the conventional treatment may have appeared for the past two decades. Carefully interpreted, the intrinsic viscosity (at zero gradient) can still provide a reasonable estimate of the axial ratios of the protein molecules. The concept of equivalent hydrodynamic volume, sound in principle, has put the viscometry of protein solutions in a proper perspective, although the quantitative aspects of this new approach still... 

The Eq. (57) allows making the following conclusion. The increase of both /j, and (if the value is used) results in melt viscosity reduction. The indicated factors, critical for oiganoclay, are not taken into account again in continuous melt viscosity treatment for polymer composites (the Eq. (42)). 

The collection of representative reservoir fluid samples is important in order to establish the PVT properties - phase envelope, bubble point, Rg, B, and the physical properties - composition, density, viscosity. These values are used to determine the initial volumes of fluid in place in stock tank volumes, the flow properties of the fluid both in the reservoir and through the surface facilities, and to identify any components which may require special treatment, such as sulphur compounds. 

Analysis of certain papers requires special treatment before they can be disintegrated properly. Papers containing synthetics, tars, asphalt, mbber, viscose, or wet-strength resins must be analyzed individually (see TAPPI T401) (20). Dyes or colors must be removed from highly colored papers before examination. The method of dye removal depends on the type of dye. 

The polymers exist in saline solution as tightly coiled chains and are readily adsorbed owing to relatively low solubiUty in hard water. Subsequent injection of soft, low salinity water uncoils the adsorbed polymer chains increasing water viscosity and reducing rock permeabiUty. This technology could also be used to reduce the permeabiUty of thief 2ones adjacent to injection wells. However, mechanical isolation of these 2ones may be necessary for cost-effective treatments. 

The iatroduction of a plasticizer, which is a molecule of lower molecular weight than the resia, has the abiUty to impart a greater free volume per volume of material because there is an iucrease iu the proportion of end groups and the plasticizer has a glass-transition temperature, T, lower than that of the resia itself A detailed mathematical treatment (2) of this phenomenon can be carried out to explain the success of some plasticizers and the failure of others. Clearly, the use of a given plasticizer iu a certain appHcation is a compromise between the above ideas and physical properties such as volatiUty, compatibihty, high and low temperature performance, viscosity, etc. This choice is appHcation dependent, ie, there is no ideal plasticizer for every appHcation. 

The temperature dependence of melt viscosity at temperatures considerably above T approximates an exponential function of the Arrhenius type. However, near the glass transition the viscosity temperature relationship for many polymers is in better agreement with the WLF treatment (24). 

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,... 

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