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Abstract:The paper addresses techniques for checking the performance of rotational rheometers with coneplate, plate-plate, or concentric cylinder geometry. We focus on the determination of the viscosity as a function of the shear rate and of the magnitude of the complex viscosity as a function of the angular frequency. After summarizing the relevant definitions and test modes, we show examples of measurements in the linear viscoelastic range, and applications of the Cox-Merz relationship. Sources of reference fluids with defined viscosities are presented, and their use in tests for verification of accuracy is demonstrated. Relevant issues, predominantly for Newtonian reference liquids, are the exploration of measurement limits, related either to the shear rate range or to reliably accessible viscosity levels. Viscoelastic reference samples are also discussed. Prerequisites for sample preparation and loading are addressed. In particular, we present recommendations based on experience from various laboratories. Finally, we discuss the problem of temperature calibration, presenting techniques that allow the determination of the true sample temperature for a given set temperature of the rheometer. This paper summarizes contributions from various industrial and academic laboratories.

No abstract

The paper addresses techniques for checking the performance of rotational rheometers with coneplate, plate-plate, or concentric cylinder geometry. We focus on the determination of the viscosity as a function of the shear rate and of the magnitude of the complex viscosity as a function of the angular frequency. After summarizing the relevant definitions and test modes, we show examples of measurements in the linear viscoelastic range, and applications of the Cox-Merz relationship. Sources of reference fluids with defined viscosities are presented, and their use in tests for verification of accuracy is demonstrated. Relevant issues, predominantly for Newtonian reference liquids, are the exploration of measurement limits, related either to the shear rate range or to reliably accessible viscosity levels. Viscoelastic reference samples are also discussed. Prerequisites for sample preparation and loading are addressed. In particular, we present recommendations based on experience from various laboratories. Finally, we discuss the problem of temperature calibration, presenting techniques that allow the determination of the true sample temperature for a given set temperature of the rheometer. This paper summarizes contributions from various industrial and academic laboratories.

Communications even in case of mercury peaks in the raw gas. As a functional alternative to the MercOx process, an acid and alkaline scrubber, a carbon-entrained bed reactor, and a fabric filter can be combined to remove the flue gas components listed above. In the case of the MercOx process, however, investment costs are far smaller, due to its reduced technical expenditure. Hydrogen peroxide represents a comparably inexpensive oxidant. This and the fact that a small pressure drop only is generated in the MercOx stage result in low operation costs. The consumption and, hence, the costs of hydrogen peroxide depend on the initial SO 2 concentration. At an SO 2 content of 100 mg/m N 3 , for example, H 2 O 2 costs to the amount of about 2 Euro per hour would be incurred for the MercOx scrubber in SAKAB. Here, costs of 1 kg of H 2 O 2 solution (35 %) are assumed to be 0.2 Euro and the calculation holds for a flue gas volume flow of 45,000 m N 3 /h (dry).Compared to the large amounts of loaded adsorbent, which have to be disposed of when using the carbon entrained-bed process, the MercOx process produces relatively small amounts of sludge in the filter press only. Hence, the waste management and disposal costs are relatively low. Disposal costs are further reduced by highly concentrated residues. _______________________ Morphology Development of Polymer Blends in Complex Flow FieldsBy M. Mours*, M. Laun, F. Oosterlinck, I. Vinckier, and P. MoldenaersPolymer blends are an economically interesting alternative when it comes to the development of materials with new or improved properties. These properties strongly depend on the underlying morphology, which is affected by, among other things, the mechanical and thermal history of the blend during preparation and processing. The influence of the typically complex flow fields in processing equipment, on the morphology, is still poorly understood. A completely immiscible concentrated PS/PMMA model blend was subjected to different types of shear, elongation and combined flow fields.Droplet deformation, break-up and coalescence in these flows were studied. While the well-known models for shear flow were found to be valid for the system under investigation, interesting effects were seen for uniaxial and biaxial extensional flow. The morphology development in one type of complex flow field, namely capillary entrance flow, is described.