Viscosity measurement procedure

Procedures for determining ash, moisture, solution preparation, and viscosity measurements can be found in manufacturers product bulletins (40,41) andin ASTMD2364-69 (65). 

Procedures for determining the ash content and moisture level, solution preparation, and viscosity measurement techniques are given in the manufacturer s hterature (50). 

Viscosity. The measurement procedure for API funnel viscosity is the same as for water-base muds. Since temperature affects the viscosity, API procedure recommends that the mud temperature should always be recorded along with the viscosity. 

Perturbed and unperturbed polymer dimensions deduced from intrinsic viscosity measurements, according to procedures which will be discussed later, are given in Table XXXIX of Chapter XIV. The... 

Polyethylene is, depending on the molecular weight, a waxy or solid, crystalline substance. Following the above-mentioned procedure, a high molecular crystalline product with a melting range around 130 C is obtained. At room temperature it is insoluble in all solvents. At higher temperatures (100-150 °C) it can be dissolved in aliphatic and aromatic hydrocarbons.Viscosity measurements can be performed in xylene,tetralin or... 

The diquaternary salts of 4,4 -bipyridine are strong electrolytes and are completely dissociated in water.Thermodynamic and viscosity measurements for solutions of paraquat dichloride in water have been obtained,and enthalpy data have been determined. ° Distribution of the positive charges in the paraquat dication has been calculated from a quantum mechanical procedure." There has been much interest in the spectra of diquaternary salts of 4,4 -bipyridine ... 

Repeat the procedure described in step no. 6, but this time, with the aid of a Pasteur pipet, add one drop of 0.1 M HC1 both to the 3-mL buffer solution, as well as to the 3-mL DNA solution. Measure the pH and the efflux times of both buffer and DNA solutions and record them (16-19) on your Report Sheet. Make sure that you empty the viscometer after each viscosity measurement. 

Measurement of conversions of various formulations at various EB doses can be used to rank the reactivity of the formulation. A particularly useful procedure has been to prepare a standard mixture of an acrylate resin with various reactive diluent monomers in order to compare the volatility and reactivity of new monomers. For these studies, a mixture of 40 weight % of a Bis-phenol A epoxy dlacrylate resin with 60% of the test liquid monomer has proved convenient. A viscosity measurement of the mixture also provides information on the relative viscosity reducing ability of the test monomer. Illustrative examples of these measurements are shown in Table I and Figure 1. Mote from these examples that a monofunctional monomer, Monomer B, can be used to provide the low volatility and high reactivity typical of the multifunctional monomers, while also serving to reduce the crosslinking. Many other available monofunctional monomers are found to be either more volatile or less reactive than Monomer B. 

Note The agitator may be fabricated from stainless steel or glass as shown in Fig. 7. Where this procedure is specified for viscosity measurements by reference in other monographs, equivalent three-blade agitators may be used. Agitators are commercially available from Div-tech Equipment Company, Cincinnati, Ohio, or from Hercules, Inc., Wilmington, Delaware. 

The procedures outlined below do not remove the effects of polymer-solvent interactions, and so A/v of a particular polymer sample will depend to some extent on the solvent used in the solution viscosity measurements (Section 3.3.1). 

Fractionation depends on the differential solubility of macromolecules with different sizes. It has been displaced in many cases by size exclusion chromatography as a means for measuring molecular weight distributions, but it is till often the only practical way of obtaining narrow fractions in sufficient quantities for the study of physical properties of well-characterized specimens. It is also part of the original procedure for the calibration of solution viscosity measurements for estimation of molecular weights. 

As stated in Chapter 1, for the determination of intrinsic viscosity, [ ], of a polymer, viscosity values of several dilute solutions, when the relative viscosities ( / s) of the dispersions are from about 1.2 to 2.0, are determined. To facilitate such measurements, the so called Ubbelohde glass capillary viscometer is used that has a large reservoir to permit several successive dilutions of a polymer solution (Figure 3-19). Because intrinsic viscosity measurement is important, the test procedure for using the Ubbelohde viscometer is outlined here in brief (Cannon Instrument Co., 1982). 

Indirect measurements. Indirect methods for determining the interfacial shear viscosity include procedures in which the liquid underneath, together with the monolayer are brought into motion and the ensuing dissipation consists of a bulk and interfacial contribution. Theory is required to compute these two contributions and to subtract the former. An old method for determining the interfacial shear viscosity is the canal surface viscometer. It is based on the determination of the flow rate of a film through a narrow canal or slit under eui applied two-dimen-... 

Procedure. Viscosity measurements were usually made in a decreas-... 

Thus, by measuring the 0-jx)int (CFT or CFV) for the polymer chains (A) in the medium under investigation (which could be obtained from viscosity measurements), it is possible to establish the stability conditions for a dispersion, before its preparation. This procedure is also helpful when designing effective steric stabihsers such as block and graft copolymers. 

The pour point test is still included in many specifications but not in some (ASTM D-396, BS 2869) for assessing the pumpability characteristics of residual fuel oil (ASTM D-3245). Pour point procedures involving various preheat treatments before the pour point determination and the use of viscosity at low temperatures have been proposed. The fluidity test (ASTM D-1659) is one such procedure as is the pumping temperature test (ASTM D-3829) another test, based on viscosity measurements (IP 230), is also available. 

The polymers were synthesized by the standard NMP/K2CO3 procedure according to literature (10,11). Glass transition temperatures and thermal stability measurements (TGA) were performed on a Du Pont DSC 1090 instrument at heating rates of 10 and 5°C/min, respectively. Intrinsic viscosity measurements were determined using a Cannon- Ubbelhodhe dilation viscometer in NMP (25°C). 

The Dean and Davis method required the measurement of viscosities at two temperatures followed by a simple calculation procedure. The simplicity made this method widely appealing, and it remains so today except that the calculation has become more complicated. As developed, when the viscosities at 100°F and 210°F were determined in SUS units, the viscosities at 100°F for the two reference oils with the same viscosities at 210°F as the sample were calculated using equations or tables provided by Dean and Davis and then the VI was calculated from Equation 3.2. Since inception, viscosity measurements have changed from SUS units to centistokes and temperatures from 100°F and 210°F to 40°C and 100°C. 

A common problem for the viscosity measurements of suspensions is the presence of wall effects due to the presence of particles in the suspension. Some work has been done on the wall effects [see, e.g., Yoshimura and Prud homme (52)]. Despite the efforts put into this subject, the words of Mewis (56) still stand that there are no acceptable means in accounting for the wall effects or usable procedures to avoid wall effects available either experimentally or analytically. As shown by Wen et al. (57), the wall effects can lead to serious errors in viscosity measurements (Figure 9). The solid line in Figure 9 is the stress versus shear rate relation that they thought to be true for the system, whereas the symbols represent the experimental results from a rotational (cup-and-bob) viscometer with different gap size settings. 

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