Viscosity Consistency

An alternative reason why particle size can affect the polymer melt or solution viscosity consists of the agglomeration of the filler. The higher the dispersity of the filler the higher is its tendency to agglomeration [138-140,161]. Agglomeration, as will be shown below, affects the properties of filled polymers. 

The dependences of electron mobility on medium density and on phase change are complex and poorly understood. In Ar, Kr and Xe, the mobility increases by a factor of about 2 in going from the liquid to the solid phase. This has generated speculation that long-range order is not necessary for high electron mobility. On the other hand, electron mobility in Ne increases from 10-3 to 600 cm2v 1s 1 on solidification at 25.5 K (see Allen, 1976). In liquid He, the electron mobility above the A-point (2.2 K) varies approximately inversely with the viscosity, consistent with the bubble model. Below the A-point, the mobility... 

Physical Property Variables. These variables are concerned with the physical properties of materials with the exception of those properties which are related to chemical composition and direct mass and weight. Variables included are density and specific gravity, humidity, moisture content, viscosity, consistency, and structural characteristics, such as hardness, ductility, and lattice structure. 

Brady has noted that the high-frequency viscosity consists only of the hydrodynamic... 

Viscose is a solution of cellulose xanthate in caustic soda. This solution can be processed into rayon or cellophane. The production of viscose consists of two steps. First, certain forms of cellulose, mainly from sulfite pulp and cotton linters, are reacted with pure caustic soda. This reaction converts the -OH groups on the cellulose unit to -ONa. The caustic soda must be pure and is obtained from mercury cells. Caustic soda from diaphragm cells contains sodium chloride which makes it unusable without purification. This solution must be aged for 2-3 days. Aging reduces the length of the cellulose chain which makes it easier to dissolve into caustic soda. The second step involves the reaction of the alkali cellulose and carbon disulfide in excess caustic soda. The net reaction of viscose is ... 

TABLE 17.8 Effect of fillers in HDPE (MEI 0.50 g/10 min) on the apparent viscosity, consistency index (apparent viscosity at the shear rate of 1 s ) and povrer-law index, determined in the capiiiary rheometer (at 170°C) and the paraiiei piate rheometer (at 177°C)... 

The large variety of carbohydrate constituents available to the food manufacturer offers a broad spectrum of properties when used individually or in combinations which range from high to low with respect to sweetness, viscosity, consistency, solubility, and many others. Furthermore, the proper manipulation of these properties by the variety of processes and techniques at the disposal of the food chemist magnifies the multiple role which the carbohydrate constituents play. 

Figure 10. Pressure dependence of parameters from various models of the rheology of invert emulsion oil-based drilling fluids at various temperatures. Casson high shear viscosity Bingham plastic viscosity consistency, power law exponent, and yield stress from Herschel-Bulkley model. (Reproduced with permission from reference 69. Copyright 1986 Society of Petroleum Engineers.)...

Viscosity Consistency—Related but quite different rheological (pertaining to flow) terms. A metal ball will penetrate a viscom substance (asphaltum) no matter how long it takes, but may stay on top of a weak but highly consistent semisolid (starch paste) for an indefinite period. 

Material properties (density, viscosity, consistence, fluidity, interfadal tension in liquids with fluid particles)... 

Body n. (1) A term used loosely in the paint and adhesives industries to denote overall consistency, i.e., a combination of viscosity, density, pastiness, tackiness, etc. (2) An aspect of fabric quality, akin to drape and hand. (3) A general term referring to viscosity, consistency, and flow of a vehicle or ink. (4) Used also to describe the increase in viscosity by polymerization of drying oils at high temperatures. (5) A practical term widely used to give a qualitative picture of consistency. For Newtonian liquids, both is the same as viscosity. 

Thinner n. (1) The portion of a paint, varnish, lacquer, or printing ink, or related product that volatilizes during the drying process. (2) Any volatile hquid used for reducing the viscosity of coating compositions or components may consist of a simple solvent, or diluent or a mixture of solvents and diluents. (3) Solvents, diluents, low viscosity oils, and vehicles added to ink to reduce their viscosity, consistency or tack. 

Mixtures of aqueous electrolytes, hydrocarbons, and amphiphilic compounds have been the subjects of extensive research, especially those systems forming amorphous isotropic solutions, called microemulsions. Several books and papers have treated this subject [1-5]. The term microemulsion was first introduced by Hoar and Schulman [5]. Microemulsions are thermodynamically stable, isotropic, transparent colloidal solutions of low viscosity, consisting of three components a surfactant (amphiphile), a polar solvent (usually water), and a nonpolar solvent (oil) [1-7]. The surfactant monomers in these fluids reside at oil water interface and effectively lower the interfacial-free energy, resulting in the formation of optically clear, thermodynamically stable formulations. The innate formation of colloidal particles is typically up to nanometer scale globular droplets each... 

Figure 15 Hot melts viscosity, consistency and hardness versus temperature.

A new type of test methodology for characterizing engineering plastics has been developed. These techniques simulate the extrusion and molding process to show what a polymer would undergo in terms of shear, temperature, pressure, and residence-time deformation. The behavior of a compound can be accurately predicted prior to processing. An online-type rheometer continuously measures the viscosity of the polymer from the die on a real-time basis, and the data is used to make screw speed adjustment to keep the viscosity consistent (10). 

Uses Solubilizer, dispersant, plasticizer, lubricant, emulsion stabilizer, viscosity consistency builder in oral tablets and caplets, sol ns. and syrups, topical, rectal and vaginal preps., ophthalmic, dental and parenteral Regulatory USP, Ph.Eur., German pharmacopoeia compliance Properties Wh. solid water-sol. vise. 24-29 mPa-s (50% aq.) solid, pt. 3040 C acid no. 0.2 max. pH 4-7 (10% aq.)... 

Example 14.4 Is a shear-thinning viscosity consistent with the predictions of the Boltzmann superposition principle ... 

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