Molecular weight effects on the phase diagram of polystyrene-poly(vinyl methyl ether) blends

Ubrich, J. M.; Larbi, Fadhel Ben Cheikh; Halary, Jean Louis; Monnerie, L.; Bauer, Barry J.; Han, C. C.

doi:10.1021/ma00157a054

Cited by 42 publications

(30 citation statements)

References 5 publications

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“…The slope reduces to 1.6 and 2.2, respectively, if the critical data are considered. Therefore, the conclusions of Halary et al [2] regarding a much too large effective segment length of poly(viny1 methyl ether) in these blends are not necessary. All deviations from the simple Eq.…”

Section: Resultsmentioning

confidence: 99%

“…The index B in all equations given above corresponds to poly(viny1 methyl ether) and C to polystyrene. It is obvious that the assumption of Halary et al [2] -x being a constant parameter, i.e., c = d = 0-is a very crude one. Furthermore, a much larger variation of G with the mean MW is observed than expected from our earlier results [ 181 .…”

Section: Resultsmentioning

confidence: 99%

“…The spinodal minimum is situated at a slightly higher temperature than that of the cloud-point curve. Therefore, the further assumption of Halary et al [2] that the difference in AT between the cloud-point curve and the spinodal is independent of the blend composition is incorrect. As their experiments do not allow verification of this assumption, there should be some doubt about this method of obtaining spinodal data.…”

Section: Resultsmentioning

confidence: 99%

“…The minima of both curves differ in concentration and temperature. Within their discussion of the effect of mean molar mass, Halary et al found a correlation between the minimum of the demixing curve and the weight-average MW in the form $ p f l = 1 t [ 2 ] . This fact is usually interpreted as a polydispersity effect, but it is not a sufficient proof of the assumption that this minimum is equal to the critical point.…”

Section: Introductionmentioning

confidence: 99%

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Polydispersity Effects on the Demixing Behavior of Poly(Vinyl Methyl Ether)/Polystyrene Blends

Rätzsch

Kehlen

Wohlfarth

1988

Journal of Macromolecular Science: Part A - Chemistry

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Phase equilibrium calculations for solutions or mixtures of synthetic polymers become considerably more difficult when there is polydispersity of the polymers. To simplify the calculations, polydispersity is often neglected in the calculations or accounted for in a summary way only, and often only relatively simple free energy relations are applied. For example, Halary et al. published experimental demixing data on poly(viny1 methyl ether)/polystyrene blends. In evaluating the data the following assumptions were made: 1) the minimum of the demixing curve equals the critical point, 2 ) the X-parameter is independent of concentration and molecular weight, 3) the polydispersity may be roughly taken into account by using the formulas for monodisperse polymers and using the weight-average molecular weight. Continuous thermodynamics proves to be a suitable method to overcome the difficulties caused by polydispersity. Therefore, this method permits one to obtain detailed information on the phase equilibria in polymer sohtions and in polymer blends in a relatively easy way. To show this, the data of Halary et al. are reanalyzed by means of continuous thermodynamics. In this way, more profound knowledge may be obtained from the experimental material, e.g., a more precise determination of the critical point and a more correct location of the spinodal. 1055

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Polydispersity Effects on the Demixing Behavior of Poly(Vinyl Methyl Ether)/Polystyrene Blends

Rätzsch

Kehlen

Wohlfarth

1988

Journal of Macromolecular Science: Part A - Chemistry

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“…Existing data stem primarily from experiments concerning chemical potentials (scattering data [9][10][11][12][13] ) and phase separation studies. [14] Mixtures of Low-Molecular-Weight Liquids…”

Section: Polymer Blendsmentioning

confidence: 99%

Binary Interaction Parameters, Ternary Systems: Realistic Modeling of Liquid/Liquid Phase Separation

Wolf

2009

Macro Theory & Simulations

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The phase behavior of ternary systems (either a polymer solution in a mixed solvent or a polymer blend in a single solvent) was modeled theoretically. The modeling considers two specific features of polymers explicitly: chain connectivity and the ability to respond to changes in the molecular environment by conformational reorientation. Previously, this approach has been applied to polymer solutions in single solvents. Here it is generalized and the number of parameters is reduced to two per binary system. The calculation of the Gibbs energies of the ternary mixtures accounts for the composition dependencies of the binary interaction parameters. The following phenomena are reproduced realistically for polymer solutions in a mixed solvent and for solutions of two polymers in a common solvent: simplicity, co‐solvency, and co‐non‐solvency. The results nourish the hope that the new approach is capable of modeling phase diagrams for ternary systems by means of binary interaction parameters only.

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Miscible Polymers

Krause

Goh

1999

The Wiley Database of Polymer Properties

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Molecular weight effects on the phase diagram of polystyrene-poly(vinyl methyl ether) blends

Cited by 42 publications

References 5 publications

Polydispersity Effects on the Demixing Behavior of Poly(Vinyl Methyl Ether)/Polystyrene Blends

Polydispersity Effects on the Demixing Behavior of Poly(Vinyl Methyl Ether)/Polystyrene Blends

Binary Interaction Parameters, Ternary Systems: Realistic Modeling of Liquid/Liquid Phase Separation

Miscible Polymers

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