Influence of Shear Rate

All data have been taken from Ref. Radical scavenger AT is the distance to the demixing tem- 

First of all it must be noted that there is still chain scission at shear rates as low as 5400 s. The strong rise of (dB/dt), with the applied mechanical force measured by the shear stress iTy is seen more clearly in Fig. 20. 

The linearity of the double-logarithmic plot suggests a well-defined relationship between the two quantities which cannot be specified yet. The full analysis of the mwd gives another important result The exponent X increases upon increasing the shear rate (see Table 1 

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INFLUENCE OF SHEAR RATE ON THE INDUCTION PERIOD DURING OLIGOMER CURING... 

Figure 2.31. Influence of shear rate on decrease of an induction period in oligomer curing. An arrow shows the direction of increase in shear rate.

The phase inversion composition of (PPE/PS)/SAN blends, as calculated by the Utracki model, is shown by the ternary phase diagram in Fig. 23, highlighting the influence of shear rate and blend composition [93]. The lines separate the regions, where SAN and PPE/PS form the matrix. For example, SAN forms the continuous phase at high SAN contents, while PPE/PS appears as the continuous phase at elevated PPE/PS contents. 

A number of empirical equations have been proposed to describe the influence of shear rate on viscosity. The most popular equation represents the so-called power law formulated by Ostwald (1925) and De Waele (1923) ... 

An understanding of the rheological behaviour is necessary as PVC pastes are classified as non-Newtonian liquids and can be dilatent (shear thickening), pseudoplastic (shear thinning) or thixotropic (viscosity reduces with time under constant shear). Each process requires specific rheological characteristics and this is achieved by formulation of appropriate PVC grades and knowledge of the influence of shear rate and time under constant shear. 

Jbnsson AS. Influence of shear rate on the flux during ultrafiltration of colloidal substances. J. Membr. Sci. 1993 79 93-99. 

Fig. 19. Influence of shear rate B the average number of broken bonds per chain (Eq, (38)) vs. degradation lime for three different shear rates measured on polystyrene in rraas-decalin U, denotes the nonuniformity of the starting molecular weight distribution (P ,o/Pn,o — 1) and AT is the distance to the demixing temperature...

Fig. 20. Influence of shear rate initial rate of degradation (dB/dtX=o vs. shear rate for polystyrene dissolved in-trons-decalin AT denotes the distance to the demixing temperature...

In order to be able to Judge the injectability of a polymer solution in a pay zone, filterability tests with surface pre-fiIters alone are not sufficient. As well as the influence of shear rate within the pores of the formation the interaction between the rock matrix and polymer solution should also be considered due to the effect on processes such as adsorption and retention. 

Porter, R. S. and Johnson, J. F., Temperature dependence of polymer viscosity. The influence of shear rate and stress. The influence of polymer composition J. Polym. ScL, C15, 365-371, 373-380 (1966).-... 

When we consider non-Newtonian liquids, the viscosity is not constant, because of the influence of shear rate and time. So for non-Newtonian fluids we refer to their apparent viscosity (p ), or effective viscosity, and we have to specify the conditions of shear rate to which this applies. When we speak of time-dependent fluids, we must also specify the shear history or kinematic history, at the point that their apparent viscosity is quoted. As long as we keep these restrictions in mind for a non-Newtonian fluid, we can still think of the apparent viscosity as ... 

The influence of shear rate on membrane structure is illustrated in Figures 31.4 (Ren et al., 2002) and 31.5 (Chung et al., 2002). Figure 31.4 exhibits the cross-section morphology of hollow-fiber membranes spun at shear rates of 812 and 2436 s. Some macrovoids can be observed near the inner skin of fibers spun at a low shear rate (812 s ), while these macrovoids are apparently eliminated or suppressed when the shear rate increases to 2436 s Clearly, high shear rates modify the precipitation path and retard the formation of macrovoids. In addition, with an increase in shear rate, the membrane structure becomes... 

Figure 31.4 Influence of shear rate on the cross-section and outer skin morphology of hollow-fiher membranes spun from a polyimide solution [ left) 812 s and (right) 2436 s ] (Ren et al., 2002).

Porter, R.S., and Johnson, J.F., Temperatnre Dependence of Polymer Viscosity. The Influence of Shear Rate and Stress , Journal of Polymer... 

Rheological investigation on HPMC/SDS binary mixtures was performed in order to test influence of SDS concentration on viscoelastic properties of HPMC solution, as well as to test influence of shear rate on HPMC-SDS complex properties. Concentration of HPMC in the binary mixtures was 0.7% (>c ), while concentration of SDS was varied (0.00-2.C... 

When we consider non-Newtonian liquids, the viscosity is not constant, because of the influence of shear rate and time. So for non-Newtonian fluids we refer to their apparent viscosity i, or effective... 

Molecular orientation can also affect melt viscosity. Figure 5 displays corresponding melt viscosities measured at the same time of ultrasonic tests. The influence of shear rate and temperature on viscosity is totally reverse to that on. The viscosity decreases with increasing... 

Figures 8 and 9 show the influence of shear rate and temperature on Cg and the relaxation time of disorientation, respectively. For the disorientation process, the evolutions of Cg versus shear rate and temperature...

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