Rheology control

Water-Based Muds. About 85% of all drilling fluids are water-based systems. The types depend on the composition of the water phase (pH, ionic content, etc), viscosity builders (clays or polymers), and rheological control agents (deflocculants or dispersants (qv)). 

D. G. Peiffer, J. Bock, and J. Elward-Berry. Thermally stable hydro-phobically associating rheological control additives for water-based drilling fluids. Patent US 5096603,1992. 

Grantham, C.K. and McLaurine, H.C. "Thixotropy Without Viscosity A New Approach to Rheology Control of Oil Muds," SPE paper 15415, 1986 SPE Annual Technical Conference and Exhibition of AIME, New Orleans, October 5 8. 

Overall, the key element in many of these approaches is the complex needs of the ink to meet the needs of the deposition technique, to facilitate the formation of the desired material with appropriate properties and to facilitate the desired thickness, roughness, line resolution, and uniformity. This set of constraints will in most cases require an appropriate combination of precursors, solvents, surfactants, adhesion promoters, and rheology control agents (e.g., see Chapter 12 for more discussion).29 For new metal organic and nanoparticle precursors, the fabrication of inks is still an emerging science. 

MC is used as an adhesive in ceramics to provide water retention and lubricity in cosmetics to control rheological properties and in the stabilization of foams in foods as a binder, emulsifier, stabilizer, thickener, and suspending agent in paints, paper products, plywood as a rheology control for the adhesive in inks, and in textiles as a binder, and for coatings. 

Dickinson, E. (1997b). Enzymic crosslinking as a tool for food colloid rheology control and interfacial stabilization. Trends in Food Science and Technology, 8, 334-339. 

Despite the limited data in the area of viscosity, the results reported so far are encouraging they indicate possible applications of polyrotaxanes in rheology control and melt processability improvement. 

Kaolin has a use in plastisol formulations giving good rheological control. Calcium carbonate is also used in this area. An alternative to calcium carbonate, phyllite, has been evaluated. This material, which contains quartz, muscovite and kaolinite, was characterised on the basis of paste viscosity, gelation and fusion behaviour, and mechanical properties (70). 

Brighton, 23rd-25th April 1996, p.145-51. 42C382 UNIQUE RHEOLOGY CONTROL ADDITIVE FOR PVC PLASTISOLS... 

The most widely used synthetic and natural enhanced oil recovery polymers, such as partially hydrolyzed polyacrylamide, carboxymethyl(ethyl) cellulose, polysaccharides, or xanthan gums, are not suitable for high-temperature reservoirs (> 90 °C) with high-density brine fluid due to excessive hydrolysis and precipitation [277]. The main advantages of polymeric betaines over the mentioned standard polymers are (1) thermostability (up to 120 °C) (2) brine compatibility and (3) viscosification in brine solution [278]. Carbobetaines grafted onto hydroxyethyl cellulose were tested as a drilling-mud additive for clay hydration inhibition and mud rheological control [279]. An increase in the content of carbobetaine moieties resulted in an enhanced inhibitive abiUty, especially for sahne mud. 

Extender. A carbonate or silicate pigment that has little hiding power but which is included in paints for other useful purposes, for example, flattening, color dilution, or rheology control. It is usually considered chemically inert. 

Fly-off. The throwing-off of particles of paint from a paint roller. This is a particular instance of poor rheological control. 

Van Keken P. E., Karato S., and Yuen D. A. (1996) Rheological control of oceanic crust separation in the transition zone. Geophys. Res. Lett. 23, 1821-1824. 

Rowland A. D. and Davies H. J. (1999) Buoyancy rather than rheology controls the thickness of the overriding mechanical lithosphere at subduction zones. Geophys. Res. Lett. 26, 3037-3040. 

Pyrogenic Silica — Mechanisms of Rheology Control in Polar Resins... 

However, additional factors must be considered in order to understand and fuially predict the rheological behavior of silica-resin mixtures. In particular, the type and strength of particle interactions and the influence of adsorption processes on these interactions are key factors which govern the rheology of liquid media containing pyrogenic silica for rheology control. 

Our research interest in this field is based on the perception that these dendritic polymers could be useful as polymer-rheology control agents as well as spherical, multifunctional macromonomers. Hyperbranched polymers, which were not only thermally and chemically robust under the conditions used, but also could be economically obtained, were created to evaluate these concepts. The latter requirement led us to pursue the one-step polymerization of AB -type monomers. We will review mostly the synthesis of aromatic polymers with stable chemical linkages prepared by the single-step direct method, and we will briefly compare them with polymers made by more controlled multistep syntheses. 

The two extreme cases are zeolite (the smallest pore size) and diatomaceous earth (the largest volume of pores). Zeolites are manufactured with predesigned pore sizes to match the sizes of molecules which can fit into these pores and become absorbed into the pore area. Applications for zeolites include moisture scavenging and selective absorption of various chemical components of mixtures. Diatomaceous earth at the other end of the scale is not selective at all. The large number of pores allows it to absorb 190-600% of its own mass. Applications include absorption of liquids and regulation of rheological properties. The mechanism of rheological control is simple. When the liquid and diatomaceous earth is... 

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