Huggins viscosity constant

Huffn puff method, in oil recovery, 18 617 HUFT theory, 14 714 Huggins viscosity constant, 21 711 Hughes-Acree method, 12 266 Hull coatings, 7 203... 

There are also other quantities that are dependent on the goodness of solvents. Among them is the Huggins viscosity constant k7, which can be determined quite easily and, because of its interesting properties, seems to be suitable for direct determination of the goodness of a particular solvent [20],... 

Solution viscosities for a particular polymer and solvent are plotted in the form (rj — j o)/(cr o) against c where rj is the viscosity of a solution of polymer with concentration c g cm and /o is the solvent viscosity. The plot is a straight line with an intercept of 1.50 cm g and a slope of 0.9 cm g. Give the magnitude and units of Huggins s constant for this polymer-solvent pair. 

Flory-Huggins interaction parameter a packing coefficient, medium viscosity initial viscosity, constant... 

Huggins, Martin constants of solution viscosity Length of a dispersed particle Retardation spectrum Lamellar thickness... 

Single-point equations suppose that kn, kK and kss are constants and that kn + kK = 0.5, as is indicated by the combination of equations Huggins and Kraemer. They all include the values for relative viscosity, increment of viscosity and concentration. For example, Solomon-Ciuta (1962) proposes ... 

The intrinsic viscosity [ti] and Huggins constant Kjj were calculated according to Huggins equation (11). 

Sam- ple Nr Method for obtaining Polysaccharide yield g/L culture medium, g Polyuronides DE, PUAC, % % Molecular mass Intrinsic viscosity dlxg" Huggins constant Kh... 

Sam- ple Nr Kind of initial material for pectin extraction Extraction time min Yield of pectin, g per 200 g fresh material AUAC, % DE, % Molecul mass Mv Huggins constant Kh Intrinsic viscosity [ft] dl.g- Gel. strengtl TB... 

Here % is the Flory-Huggins interaction parameter and ( ), is the penetrant volume fraction. In order to use Eqs. (26)—(28) for the prediction of D, one needs a great deal of data. However, much of it is readily available. For example, Vf and Vf can be estimated by equating them to equilibrium liquid volume at 0 K, and Ku/y and K22 - Tg2 can be computed from WLF constants which are available for a large number of polymers [31]. Kn/y and A n - Tg can be evaluated by using solvent viscosity-temperature data [28], The interaction parameters, %, can be determined experimentally and, for many polymer-penetrant systems, are available in the literature. 

We have recently performed systematical measurements of the intrinsic viscosity of acrylamide-acrylic acid copolymers for large ranges of r and a, in the presence of CaCl2(26). Our results show that the empirical relation (14) can be extended to the case of divalent cations by using the value of 7 given in relation (15). It should then possible to predict the variation of intrinsic viscosity at infinite dilution, but at finite concentration the formation of aggregates makes difficult the determination of the Huggins constant. 

Figure2. Effect of calcium on intrinsic viscosity and Huggins constant of HPAM.

For each sample, the Flory Huggins constants (k, Eq. 5.25) were also determined (by viscosity measurements) as function of sonication time and are given in Tab. 5.17. 

The Huggins constant k characterizes the first effects of interaction on the zero-shear viscosity ... 

In many ways it would have been desirable to have obtained a continuous record during the reaction of the intrinsic viscosity, [rf], which can be found by extrapolating to zero concentration of the function rj/c. However, no convenient experimental procedure was devised for doing this, and no extrapolation formula could be used since the Huggins constant for the polymer changed during the reaction. 

Figure 14. Huggins constant, k1 and intrinsic viscosity in toluene at 25°C. for styrene-hydroxyethyl methacrylate copolymer (2.2 mole % HEM A) after crosslinking with hexamethylene diisocyanate in toluene at 80°C.

Solution Viscosity. The intrinsic viscosities [77] of the copolymers were measured for solutions in dry toluene at 25 °C. by dilution in an Ubbelohde suspended-level viscometer. Conventional plots of rj/c (18) and log (1 + r )/c (29) were found to be nonlinear for all copolymers where 77 is the specific viscosity. To get accurate values of the intrinsic viscosities and of the Huggins constants h and k2, triple plots were drawn as recommended by Heller (16). These gave the intercept 1/[iy], and fci and were determined directly from the initial slopes of the plots... 

Eq. (16.2) can be used for predicting the viscosity of a dilute polymer solution if the Huggins constant kH is known. But literature values of kH or values predicted with Eq. (16.6) are rather inaccurate. So they do not permit a good prediction of rj. 

The intrinsic viscosity as well as the Huggins constants were measured for polyMAOT and polyAOT (Table 12). The intrinsic viscosity for polyMAOT is larger than that for polyAOT, probably because of the difference in molecular weight27. The value varies significantly with change of solvent, and the Huggins constant also vary with the solvent used in a similar manner. 

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