Physical Chemistry of Foods
FIGURE6.11 Viscosity parameters of solutions of carboxymethyl cellulose (Na salt) at various ionic strengths (molar). Mark–Houwi ...
The behavior ofpolyampholytesis in some respects different. At a pH far from its isoelectric point, a polyampholyte behaves roug ...
electroneutrality forces an equal transport of Naþ. This is depicted below, where m means molar concentration. The vertical line ...
and this also holds for the Clions. Form 24 m 1 , the salt composition is nearly the same in both compartments. If a mixture of ...
restrictions to volume changes, solvent (water) will be drawn to the region close to the polyelectrolyte molecule, to even out t ...
6.4 MORE CONCENTRATED SOLUTIONS So far, we essentially considered interactions between one polymer molecule and the solvent. In ...
imply that determination of the molar mass of a polyelectrolyte via osmotic pressure should be done at very high ionic strength ...
chain overlap, but the relations between properties of the solution and polymer characteristics are different. In the domain lab ...
laws have been derived for the boundaries between the regimes in the state diagram and for some characteristic properties. We wi ...
ðb=LÞvary along the chain. Nevertheless, it may be useful to have some idea about the concentration needed for chain overlap; it ...
adjacent sub-chains are the same whether the two belong to the same molecule or not. For distances>x, i.e., at longer time sc ...
6.4.3 Viscosity Polymeric thickening agents used in foods typically are well soluble polysaccharides, with an excluded volume pa ...
FIGURE6.15 Viscosity of polysaccharide solutions. Specific viscosity at very low shear rateðZ=Zs 1 Þ 0 versus dimensionless con ...
Part of the data presented in Figure 6.15 and Table 6.5 concern polyelectrolytes, but they were obtained at fairly high ionic st ...
i.e., independent of shear rate, and high. At very high shear rate, the time allowed for entanglements to form is very short, an ...
Question 2 What is the zero shear rate viscosity of 0.25%aqueous solutions of Dextran Na-alginate at high ionic strength Locust ...
6.4.4 Gelation In a polymer solution above the chain overlap concentration,entanglements occur (Fig. 6.16). If such a solution i ...
molar concentration then is negligible. Consequently,bcrwill be very close to zero for highq, as observed. However, on precipita ...
negative for phase separation to occur. There are, however, several exceptions to this rule, for instance because DH may depend ...
polymers, and several specific interactions between groups on the polymer may play a part, implying that precise prediction of p ...
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