Viscosity viscometry

Viscosity (viscometry, viscometric data, findings, study, techniques) 119, 123-125, 134... 

In addition to the apparent viscosity two other material parameters can be obtained using simple shear flow viscometry. These are primary and secondary nomial stress coefficients expressed, respectively, as... 

Before we are in a position to discuss the viscosity of polymer melts, we must first give a quantitative definition of what is meant by viscosity and then say something about how this property is measured. This will not be our only exposure to experimental viscosity in this volume—other methods for determining bulk viscosity will be taken up in the next chapter and the viscosity of solutions will be discussed in Chap. 9—so the discussion of viscometry will only be introductory. Throughout we shall be concerned with constant temperature experiments conducted under nonturbulent flow conditions. 

Slurry Viscosity. Viscosities of magnesium hydroxide slurries are determined by the Brookfield Viscometer in which viscosity is measured using various combinations of spindles and spindle speeds, or other common methods of viscometry. Viscosity decreases with increasing rate of shear. Fluids, such as magnesium hydroxide slurry, that exhibit this type of rheological behavior are termed pseudoplastic. The viscosities obtained can be correlated with product or process parameters. Details of viscosity deterrnination for slurries are well covered in the Hterature (85,86). 

Synthetic, nonionic polymers generally elute with little or no adsorption on TSK-PW columns. Characterization of these polymers has been demonstrated successfully using four types of on-line detectors. These include differential refractive index (DRI), differential viscometry (DV), FALLS, and MALLS detection (4-8). Absolute molecular weight, root mean square (RMS) radius of gyration, conformational coefficients, and intrinsic viscosity distributions have... 

Virtually crosslinked (VC) products, 201 Viscometry, of polyamides, 161-162 Viscosity, molecular weight and, 3 VK column reactor, 175 Volatile organic compounds (VOCs), 206, 207... 

Viscometry Intrinsic viscosity [/]] conformation and flexibility. [r]], like Rg, much more sensitive than s. Accurate concentration estimates required. [6]... 

Few sets of K,a parameters were given in references 17 and 22 K and a are parameters which may depends on the fine structure i.e. rhamnose content, DE... when they play on the stiffness of the chain. Nevertheless, it seems that the viscometry must be used in carefully defined conditions to avoid aggregation which often surestimates the viscosity in that conditions, [ti] is related to the physical properties of the solution (tickening properties) but not directly to My. 

Dilute Solution Viscometry - The hydrogenated and hydroformyl ated (10%) PBD were completely soluble in toluene. Intrinsic viscosity measurements were carried out in toluene at 30°C using a Cannon-Ubbelohde viscometer. 

The viscosities of products in solution (0.5 Weight %/volume) were measured by dilute solution viscometry using a Cannon Ubellohde viscometer at 35 °C. 

Sections of several packages were tested by dilute solution viscometry in decahydronaphthalene at 135°C to determine if the failures are consistent with UV degradation. The top surface of each package was partially covered by a paper label. This label should have shielded the underlying film from UV exposure, and there should be a difference in the solution viscosity of material taken from the shielded center of the package and material taken from the UV-exposed edge. Sections from the center and edge of three samples were... 

Viscosity, defined as the resistance of a liquid to flow under an applied stress, is not only a property of bulk liquids but of interfacial systems as well. The viscosity of an insoluble monolayer in a fluid-like state may be measured quantitatively by the viscous traction method (Manheimer and Schechter, 1970), wave-damping (Langmuir and Schaefer, 1937), dynamic light scattering (Sauer et al, 1988) or surface canal viscometry (Harkins and Kirkwood, 1938 Washburn and Wakeham, 1938). Of these, the last is the most sensitive and experimentally feasible, and allows for the determination of Newtonian versus non-Newtonian shear flow. 

Shrinking of the polymer chains as a function of temperature was observed by capillary viscometry. The reduced viscosity, r]Sp/c, of polymer solutions approaches zero when the polymers are in their fully collapsed compact state and flow freely through the capillary. Above the cloud point, rjSp/c increases, which is indicative of aggregate formation. At low temperatures the... 

In addition, data on the size, shape and solvation of the polymer particles in aqueous solutions at temperatures below and above the transition phenomena registered by HS-DSC have been obtained [42]. Table 2 shows the results of capillary viscometry and light scattering experiments for the fractions p and s of poly(NVCl-co-NVIAz) synthesized at 65 °C from the feed with the initial molar comonomer ratio equal to 85 15. Since fraction p precipitates from the aqueous solution at temperatures > 34 °C, its intrinsic viscosity can be determined only at 20 °C, whereas for the fraction s such measurements were possible above and below the temperatures of the HS-DSC-registered conformational transition. 

Viscometry is used to measure average molar masses too [1-3]. It is an indirect method, since the measured quantity is the intrinsic viscosity (TV), which is related to the average molar masses calibration by a peculiar formula, called the Mark-Huwink-Sakurada equation [1-3]. 

The viscosity is measured with the help of a viscometer and the method is known as viscometry. Molecular weight Determination by Viscometry... 

For Molecular weight determination by viscometry we do not need absolute h value, viscosity measurements may be carried out in simple Ostwald Viscometer. Because of (the non-Newtonian behaviour of most macromolecular solutions at high velocity gradients in the capillary, the viscometer dimensions are chosen in such a manner that the viscosity gradient is the smallest possible. 

The laboratory technique for measuring viscosity is called viscometry (sometimes viscosimetry), and the device in the laboratory used to measure viscosity is called a viscometer (sometimes viscosimeter). 

In a research and development laboratory at the Dow Chemical Company in Midland, Michigan, rotational viscometry experiments on various dilutions of a test fluid, such as corn syrup, can generate the required data. Once various challenges are overcome, such as obtaining a uniform and constant temperature throughout the fluid and dealing with unusual physical behaviors of the test fluid, accurate viscosity measurements can be made and the project to optimize mixing performance can move forward. 

Define rheology, shear force, shear stress, shear rate, Newtonian fluid, dynamic viscosity, centi-poise, kinematic viscosity, centistokes, viscometry, and viscometer. 

In capillary viscometry, the fluid being measured flows through a capillary tube. How is this helpful in measuring viscosity ... 

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