Viscosity test methods

BROOKFIELD recently announced it offers two hands-on courses that can help users of its instruments to get the most out of their viscosity test methods. These one-day training sessions can be scheduled to take place at Brookfield s Middleboro, MA, headquarters and at major metropolitan areas across the U.S. Courses can also be conducted at customers facilities, where content can be adapted to specific product applications. For more information, call (800) 628-8139 or (508) 946-6200, or visit www.brookfieldengineering.com/ser-vices/educational-programs. 

Parks, R. A., Re-evalnation of Dilute Solution Viscosity Test Methods Proves Boon to PVC Quality Control, Plast. Design and Processing (Ang. 1974), pp. 24-25. 

Penetrability is the depth, expressed in tenths of a millimeter, a standard steel needle penetrates into a bitumen sample at 25°C. The needle carries a weight of 100 g and the test is applied for five seconds. The corresponding test method is relatively difficult to carry out and is defined in France by the standard NF T 66-004, and in the USA by the method ASTM D 583. Penetration is related to the viscosity. 

Analytical and test methods for the characterization of polyethylene and PP are also used for PB, PMP, and polymers of other higher a-olefins. The C-nmr method as well as k and Raman spectroscopic methods are all used to study the chemical stmcture and stereoregularity of polyolefin resins. In industry, polyolefin stereoregularity is usually estimated by the solvent—extraction method similar to that used for isotactic PP. Intrinsic viscosity measurements of dilute solutions in decahn and tetraHn at elevated temperatures can provide the basis for the molecular weight estimation of PB and PMP with the Mark-Houwiok equation, [rj] = KM. The constants K and d for several polyolefins are given in Table 8. 

Standardized test methods for analyzing the chemical composition, viscosity, and physical properties of cellulose esters have been adopted by the ASTM and are described in substantial detail (110). 

Testing. The Technical Association of the Pulp and Paper Industry (TAPPl) gives test methods that are widely used by kaolin suppHers to the paper iadustry. These iaclude tests for viscosity, viscosity stabiUty, brightness, pH, particle size distribution, moisture content, and screen residue (12). 

Testing. Various test methods are provided by ASTM (16). These iaclude pigment tests of importance such as chemical analysis, presence of oversize particles, oil absorption, particle size distribution, degree of dispersion, presence of soluble components, etc. Numerous tests are also given by ASTM for the properties of filled and unfilled polymers. These iaclude, for example, such properties as impact resistance, stiffness, viscosity, tear resistance, hardness, color, and electrical resistivity. 

The types of sedimentation encountered in process technology will be greatly affected not only by the obvious factors—particle size, hquid viscosity, sohd and solution densities—but also by the characteristics of the particles within the shiny. These properties, as well as the process requirements, will help determine both the type of equipment which will achieve the desired ends most effectively and the testing methods to be used to select the equipment. 

ASTM, Standard Test Method for Estimation of Molecular Weight (Relative Molecular Mass) of Petroleum Oils from Viscosity Measurements, ASTM Standard D-2502-92, 1992. 

The physical properties important for the projected use of hydraulic fluids are viscosity, density, foaming behavior, and fire resistance. There is no generally recognized test method for measuring flammability of hydraulic fluids, although various test methods maybe utilized (Moller 1989). 

Saybolt Universal Seconds (SUS) are used to measure viscosity. The efflux time is the SUS required for 60 mL of a petroleum product to flow through the calibrated orifice of a Saybolt Universal viscometer, under carefully controlled temperature and as prescribed by test method ASTM D 88. This method has largely been replaced by the kinematic viscosity method. SUS is also called the SSU number (Seconds Saybolt Universal) or SSF number (Saybolt Seconds Furol). 

A test method to evaluate the shear stress capability of a seal material is reported [36], An electrolyte-anode-electrolyte trilayer was glass sealed to two metal interconnect plates as shown in Figure 5.11. Shear testing was done in two different modes, constant loading rate and constant displacement rate, to determine the shear modulus and viscosity. 

Another test method (ASTM D4052) covers the determination of the density or specific gravity of viscous oil, such as residual fuel oil, that are liquids at test temperatures between 15 and 35°C (59 and 95°F). However, application of the method is restricted to liquids with vapor pressures below 600 mmHg and viscosity below 15,000 cSt at the temperature of test. In addition (and this is crucial for residual fuel oil), this test method should not be applied to samples so dark in color that the absence of air bubbles in the sample cell cannot be established with certainty. 

The substitution of more benign solvents in many formulations will have global ramifications. For example, water-reducible coatings are products where the solvent system used to disperse and suspend solids is primarily water. The remainder of the solvent system may contain liquids that are classified as flammable or combustible liquids. Inherent limitations in these systems relate to product viscosity, accuracy in predicting overall fire hazard, abihty to assess physical changes of state when a product is tested, and test method rehabihty and ease of use (Scheffey and Tabar, 1996). 

Dissolve 5.00g of the specimen in 76g of toluene and 19g of ethanol conforming to Spec O—E—760. Determine the viscosity at 25° according to Method 305 of Federal Test Method Standard No 791, except that the results in cent stokes should be converted to centipoises as follows ... 

Use Method 1001 of Federal Test Method Standard No 791, except that, due to the high viscosity of the material, cooling water at 40—45° shall be substituted for the ice-water in the condenser... 

Solution viscosity is an excellent method for quality control for relatively uniform polymer samples. There is an ASTM test method for determining inherent viscosity (ASTM D 4603) that uses polyethylene terephthalate) and one for determining intrinsic viscosity of cellulose (ASTM D 1795) that describes a one-point method for estimating intrinsic viscosity. The result is useful as it relates viscosity to molecular weight, which is useful for checking different batches of polymer in a production line to help ensure uniformity. 

However, the viscosity at which this transition takes place cannot easily be calculated because many high jyiscosity fluids are non-Newtonian. This means that the viscosity varies according to the rate at which the fluid is flowing. It is therefore best to carry out a small-scale test in order to determine whether or not flow will be laminar. A possible test method is given in A2.3.3. Chapter 10 gives more information on high viscosity fluids. 

Viscosity. It shall be detd in accordance with method 305.6 of Federal Test Method Std 79IB (Jan 1969) (ASTM Method D445—65). The time is measured for a fixed vol of the... 

Since the apparent viscosity of a non-Newtonian fluid holds only for the shear rate (as weii as temperature) at which it is determined, the Brookfield viscometer provides a known rate of shear by means of a spindle of specified configuration that rotates at a known constant speed in the fluid. The torque imposed by fluid friction can be converted to absolute viscosity units (centipoises) by a multiplication factor. See viscosity, shear stress. The viscosities of certain petroleum waxes and wax-polymer blends in the molten state can also be determined by the Brookfield test method ASTM D 2669. 

---