Huggins constant poly

Linear water-soluble anionic poly(acrylamide-co-ammonium acrylate) has been prepared by a water-in-oil polymerization. These materials are characterized by a Huggins constant in brine greater than 0.75 and a storage modulus for a 1.5 wt% actives polymer solution at 4.6 Hz greater than 175 Pa. These agents are particularly useful as drainage aids and contamination control aids in papermaking. 

FIGURE 2 Huggins constant versus blend composition for two ternary polymer blend solutions in chloroform, PHB blended with poly(ethylene oxide) (PEO)—( ), and poly(e-caprolactone) (PCL)—(o), soM curves represent regression curves after Equation (22) dashed curves were calculated with AK = 0. 

Effect of Salt Type on the Intrinsic Viscosity and the Huggins Constant of Poly(METMA/MES). 

The intrinsic viscosity [q] increases with the molar mass (see Concentration and molar mass in Chap. 5) even at the same concentration and for the same solvent. The resulting expansion of the polymer coils leads to an increase of the interactions and therefore to an increasing slope KnX[qY. Since the Huggins constant Kii is independent of the molar mass for a specific polymer solvent system, the increasing intrinsic viscosity solely causes the increasing slope. This is shown in Fig. 5.4 for sodium poly(styrene sulfonate) of different molar masses at a constant concentration. 

Fig. 5.4. Reduced viscosity /j ed function of the concentration c for sodium poly(styrene sulfonate) (PSSNa) of different molar masses in aqueous solution.The second virial coefficient of the viscosimetry, is equivalent to the slope of the curves and is given for each molar mass. The Huggins constant Ky is constant and independent of the molar mass. Data from [35,91]...

As pointed out in Chapter III, Section 1 some specific diluent effects, or even remnants of the excluded volume effect on chain dimensions, may be present in swollen networks. Flory and Hoeve (88, 89) have stated never to have found such effects, but especially Rijke s experiments on highly swollen poly(methyl methacrylates) do point in this direction. Fig. 15 shows the relation between q0 in a series of diluents (Rijke assumed A = 1) and the second virial coefficient of the uncrosslinked polymer in those solvents. Apparently a relation, which could be interpreted as pointing to an excluded volume effect in q0, exists. A criticism which could be raised against Rijke s work lies in the fact that he determined % in a separate osmotic experiment on the polymer solutions. This introduces an uncertainty because % in the network may be different. More fundamentally incorrect is the use of the Flory-Huggins free enthalpy expression because it implies constant segment density in the swollen network. We have seen that this means that the reference dimensions excluded volume effect. 

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