Additives of viscosity

LMC is used in underwater concrete for both new construction and repair. The important requirements to obtain antiwashout capability, such as segregation resistance, flowability, self-leveling characteristics and lower bleeding are provided by the addition of viscosity-enhancing polymeric admixtures at polymer-cement ratios of 0.2-2.0%. These admixtures are water-soluble polymers, and classified under two groups, viz., cellulose types such as methyl cellulose and hydroxy ethyl cellulose and polyacrylamide types such as polyacrylamide and polyacrylamide-sodium acrylate [101]. 

PVC plastisols or pastes should have a viscosity suitable for handling and storage, as well as the manufacturing process. This is necessary for thinning under the appropriate shear conditions. Paste PVC resins (or blends of resins) are designed to satisfy a particular rheology profile, but sometimes the addition of viscosity modifiers is necessary. Fumed silicas are typically used. Calcium sulfonate gels have also been promoted (458). 

Dope - Any thick liquid or pasty preparation used for further processing such as coating or fiber spirming. A polytetrafluoroethylene (PTFE) dope prepared by the addition of viscose, to PTFE dispersion, is spun to manufacture yam. 

Distances in solution at physiological temperatures can at least be estimated under conditions where the reorientation rate of the spin-spin-vector is reduced by other mechanisms, e.g., embedding the proteins in membranes or upon addition of viscosity agents [79]. In this case the dipole-dipole interaction is partly averaged out, making accurate distance measurement difficult. Quantitative... 

To increase the density of water sugar syrup can be added. An increase of the viscosity can also be achieved by the addition of viscosity enhancing substances. The character of the sediment may be influenced by electrolytes or surfactants. 

If the concentration of solids, for instance zinc oxide, is high enough, the suspension is relatively stable and the addition of viscosity enhancers is not necessary. Furthermore viscosity enhancers may be unsuitable if they ruin specific effects such as the cooling effect from evaporation of water or alcohol. If the addition of preservatives is not desirable, e.g. in case of a large skin area that is affected, the preparation should be dispensed in single-use (or at least few times use) containers and the use period should be restricted to a few days. 

The effects of changing the miscibility of a binary system in a melt may exert an influence on the deviation of the viscosity of a melt from the additivity of viscosities of components. 

The concentrate storage tanks for slurry pipelines are essentially large tanks with agitators (Figure 12-5). A smaU pump test loop near these tanks is used to test the concentrate before feeding it to the pipeline pumps. Feed is essentially from the thickeners, but continuous agitation in the tank and addition of viscosity control agents, corrosion inhibitors, and even some dilution water are part of the process. 

---