Solubility of Polymers

Abstract

Detailed knowledge concerning the phase state (homogeneous or coexistence of two or more condensed phases) of polymer containing mixtures is indispensible in virtually any area related to the production or application of macromolecules. In addition to this qualitative information it is for many purposes highly desirable to dispose of quantitative data regarding solvent quality or, more generally, with respect to the thermodynamic interaction between the components of the mixtures. This contribution starts with a brief presentation of the thermodynamic criteria deciding on the phase state and presents the experimental methods used in this area. The next section gives an overview on typical behaviors of polymer solutions and polymer blends; it is followed by a part recalling widely used theoretical approaches. Finally, a data section collects solvents and non‐solvents for a large number of polymers and presents some examples for the quantitative thermodynamic description of polymer solutions.

How to Force Polymer Gels to Show Volume Phase Transitions

“…Most frequently used are power series dependences and the closed form dependences where a , b , and c are constants. Wolf et al − analyzed the concentration dependences in detail and proposed several variants; the favored one reads The values of the constants are tabulated in a review chapter . The concentration dependences of the interaction function g (ϕ 2 ) in Δ G mix can be transformed into χ­(ϕ 2 )…”

Dextran‐Based Polycations: Thermodynamic Interaction with Water as Compared With Unsubstituted Dextran, 2 – Flory/Huggins Interaction Parameter

“…For this temperature, literature reports [12] exist of Flory-Huggins interaction parameters for the water/dextran system and a moderately concentrated solution (filled asterisks at low w values). be performed in terms of the three parameters (a, n and zl) of Equation 4 and their dependence on the fraction f of charged monomer units. Figure 10 shows this dependence for a, the parameter that quantifies the effect of separating two contacting polymer segments by the insertion of a solvent molecule in the limit of high dilution, keeping all conformations unchanged.…”

“…The obvious question one must ask in this context is about the universality of this result. According to a recent comprehensive collection [4] of vapor-pressure data above polyelectrolyte solutions, only very few cover the large composition range required. The most-relevant information [13] that we could find concerns solvent activities of aqueous solutions (no salt added) of .…”

“…The systems studied so far comprise linear and branched polymers in organic or aqueous solvents, but all of the macromolecules have been uncharged; a recent progress report [3] summarizes these results, which are also documented in the form of a database. [4] By means of the work we are presenting here, we wanted to investigate whether the above-mentioned approach also works for polyelectrolytes and, if so, how the values of the parameters differ from those typically obtained so far. In order to investigate how the transition to polyelectrolyte behavior takes place, we have studied four charged dextran derivatives containing 11, 24, 74 and 90% randomly distributed monomeric units carrying a…”

“…4 show the reduced vapor pressures measured as a function of composition for the unsubstituted dextran and for the four cationic derivatives at the three temperatures under investigation.…”