Dispersion viscosity

In the general case the dispersion viscosity (i.e. a filled system) as a function of concentration r (cp) can be presented as a power series ... 

The representation of the dispersion viscosity given above related to suspensions of particles of spherical form. Upon a transition to anisodiametrical particles a number of new effects arises. The effect of nonsphericity is often discussed on the example of model dispersions of particles of ellipsoidal form. An exact form of particles to a first approximation is not very significant, the degree of anisodiametricity is only important, or for ellipsoidal-particles, their eccentricity. 

E. B. Brandes and F. C. Loveless. Dispersants and dispersant viscosity index improvers from selectively hydrogenated polymers. Patent WO... 

There have been some examples of the use of LDMS applied to the analysis of compounds separated via TLC, although not specifically dealing with polymer additives [852]. Dewey and Finney [838] have described direct TLC-spectroscopy and TLC-LMMS as applied to the analysis of lubricating oil additives (phenolic and amine antioxidants, detergents, dispersants, viscosity index improvers, corrosion inhibitors and metal deactivators). Also a series of general organics and ionic surfactants were analysed by means of direct normal-phase HPTLC-LMMS [837]. Novak and Hercules [858] have... 

The reduced dynamic modulus of rigidity, obtained from the dispersion viscosity, is of the form (10) ... 

Step A Time required to disperse viscosity-building agent in water. bStep B Time required to dissolve water-soluble formulation ingredients in water. 

It is frequently desirable to be able to describe and/or predict dispersion viscosity in terms of the viscosity of the continuous phase (t]0) and the amount of dispersed material. A very large number of equations have been advanced for estimating emul-... 

When solids are present in emulsions, the volume fractions of the particles and the droplets are usually not additive for the purpose of predicting overall dispersion viscosity. A number of different kinds of behaviours can result, depending on the sizes and shapes of the particles versus the droplets, and upon whether they exist as kinetically independent entities, whether the particles exist in adsorption layers surrounding the droplets, or dispersed within the droplets themselves, or a combination of all of the above. Pal et al. [382] and Nasr-El-Din [85] discuss the rheology of emulsions containing solids in some detail. 

Viscosity higher than dispersion Viscosity almost the same as of... 

Many kinds of native and modified starches are being used on the size press.207 The governing factors are dispersion viscosity, film formation and resistance to retrogra-dation. For low-cost applications, native corn starch is depolymerized in the paper mill by enzymic or thermal-chemical conversion. In-plant converted starches are... 

M and M are not related only to mass they are equally a function of charge, solvent activity, and concentration. Some generalizations can nevertheless be made about the DP the lowest DP stimulates the highest kinetic activity at the same weight concentration low DP polysaccharides are more soluble and reactive than high DP polysaccharides a high DP is necessary for dispersion viscosity measurably above that of water. 

All the above formulas are one-parameter equations, i.e. they relate the dispersion viscosity only to the volume fraction of particles contained in it. This limits the range of applicability of the equations to not very high dispersion concentrations. To take account of the influence of the structure of concentrated dispersions on their rheological behavior, Robinson [12] suggested that the viscosity of dispersions is not only propertional to the volume fraction of solid phase, but is also inversely proportional to the fraction of voids in it. (At about the same time Mooney [40], who proceeded from a hydrodynamic model, arrived, using theoretical methods, at the same conclusion). Robinson s equation contains the relative sedimentation volume value — S, which depends on the particle size distribution of the dispersion... 

An impressive review of different formulas for the dependence of viscosity on concentration was published by Rutgers [16]. Orr and Dalla Valle [17] derived a formula relating the dispersion viscosity to the filler porosity in a different form ... 

The ratio of mean granule diameters (Dt/Do) can be used to correlate consistency coefficient data of starch dispersions. At low values of cQ, the granules were sufficiently apart and did not affect dispersion viscosity substantially. As cQ increased... 

Addition of gluten to 6.5-6.6% (w/w) dispersions of different starches at a 1% level ealeulated on dry stareh basis inereased the G of wheat and rye starches, lowered that of maize stareh but did not affeet the modulus of barley, triticale and potato starehes (Lindahl and Eliasson, 1986). G was also found to increase with increasing amounts of gluten (1-4%) added to the wheat starch. Studies on starches with different amylose/amylopectin ratios suggest that gelatinization of amylopectin and not amylose favors a synergistie interaetion with proteins leading to an increase in dispersion viscosity (Chedid and Kokini, 1992 Madeka and Kokini, 1992). 

The properties of thermosetting and thermoplastic resin systems are continually improved to meet increasing performance requirements of end users. One way to enhance material properties is to incorporate nano-modifiers, based on elastomeric silicone particles, which are optionally grafted with other (acrylic) polymers to control dispersibility, viscosity, and other parameters. As an example, epoxy resin formulations have been modified with silicone nanospheres to improve low-stress behavior. Table 1 shows the outstanding fracture toughness improvement of silicone coreshell nanospheres, even at very low particle loading levels. 

Alginic acid hydrolyzes slowly at warm temperatures producing a material with a lower molecular weight and lower dispersion viscosity. 

Viscosity (dynamic) 4.86Pas (4860cP) for a 1% w/v dispersion. Viscosity is dependent upon temperature, time, concentration, pH, rate of agitation, and particle size of... 

---