Pressure-pulse-induced critical scattering of oligostyrene in n-pentane

Kiepen, Friedheinz; Borchard, W.

doi:10.1021/ma00184a041

Cited by 29 publications

(11 citation statements)

References 16 publications

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“…Pressure is transmitted hydraulically to the samples via a mercury seal, and cloud and spinodal points are detected by a light scattering technique. 1,4,7 In the region of the phase diagram of interest, PS/PN solutions are characterized by upper and lower consolute branches separated by a homogeneous one-phase region (see Figure 1). The most convenient way to determine cloud and spinodal points using the apparatus is to first place the sample into the homogeneous region at elevated pressure, then induce precipitation by lowering pressure, all the while monitoring low-angle scattering intensity.…”

Section: Methodsmentioning

confidence: 99%

Isotope and Pressure Dependence of Liquid−Liquid Equilibria in Polymer Solutions. 7. Solute and Solvent H/D Isotope Effects in Polystyrene−Propionitrile Solutions

Łuszczyk

Hook

1996

Macromolecules

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Cloud and spinodal loci have been obtained as functions of pressure (P), temperature (T), polymer segment number (r), segment fraction (ψ), and H/D substitution on solute (zD) or solvent (yD) for polystyrene-h/propionitrile-h (PSh/PNh) solutions, polystyrene-h/propionitrile-2,2-d2 solutions (PSh/PNd), and polystyrene-d/propionitrile-h solutions (PSd/PNh). A light scattering technique was employed. An increase in pressure or an increase in the H/D ratio in the solvent (or decrease in the polymer H/D ratio) increases the region of miscibility. The solutions show upper and lower branches which may join at hypercritical points depending on the pressure, molecular weight, or solvent H/D ratio. A least-squares technique to fit experimental data to the continuous mean-field thermodynamic description of polymersolvent demixing developed by Luszczyk, Rebelo, and Van Hook (Macromolecules 1995, 28, 745) is described and then illustrated by application to the PS/PN data.

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Section: Methodsmentioning

confidence: 99%

Isotope and Pressure Dependence of Liquid−Liquid Equilibria in Polymer Solutions. 7. Solute and Solvent H/D Isotope Effects in Polystyrene−Propionitrile Solutions

Łuszczyk

Hook

1996

Macromolecules

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“…Scattered (I sc ) and transmitted light (I tr ) are corrected for density fluctuations, reflections, and multiple scattering effects according to Debye (17,18) and Kiepen and Borchard. (19) Following these authors and Luszczyk et al (1) the cloud-point is the point on the 1/I sc,corr against pressure ( p) or temperature (T ) least squares fits where the slope changes abruptly. The operational spinodal point will be taken at the interception point where 1/I sc,corr = 0.…”

Section: Experimental Equipment and Techniquementioning

confidence: 99%

(Liquid + liquid) equilibria of (polystyrene + nitroethane). Molecular weight, pressure, and isotope effects

Sousa

Rebelo

2000

The Journal of Chemical Thermodynamics

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“…Scattered light intensity is captured at very low angle (2 < 2θ (deg) < 4) in the outer part of a bifurcated optical cable [8], while transmitted light is captured in the inner portion of this cable. Scattered (I sc ) and transmitted light (I tr ) are corrected for density fluctuations, reflections, and multiple scattering effects according to Debye's theory [9]. The cloud-point (cp) is the point on the 1/I sc,corr against pressure (P) or temperature (T) least-squares fits where the slope changes abruptly.…”

Section: Equipment and Techniquementioning

confidence: 99%

Phase behavior of (polyacrylamides + water) solutions: concentration, pressure and isotope effects

Azevedo

Rebelo

Ramos

et al. 2001

Fluid Phase Equilibria

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Phase diagrams of poly(N-isopropylacrylamide) (PNIPAAM) as well as of hydrophilically-modified copolymers in aqueous solution were determined. A high-accuracy He-Ne Laser scattering technique was used for the detection of operational spinodal (sp) and cloud-point (cp) curves. Polymer concentration was varied from 0.5 to 20 wt.%. In the case of copoly(PNIPAAM/vinylsaccharide) several different chain lengths were considered. Pressure (up to 400 bar) and solvent isotope effects were studied. We predict a closed-loop type phase diagram for the copolymers, which presents an estimated hypercritical point in H 2 O solutions at M w ∼ 0.5 × 10 5 , although only lower critical solution temperature (LCST) is experimentally accessible. At lower molecular weights, the solutions are always in the one-phase region.

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Pressure-pulse-induced critical scattering of oligostyrene in n-pentane

Cited by 29 publications

References 16 publications

Isotope and Pressure Dependence of Liquid−Liquid Equilibria in Polymer Solutions. 7. Solute and Solvent H/D Isotope Effects in Polystyrene−Propionitrile Solutions

Isotope and Pressure Dependence of Liquid−Liquid Equilibria in Polymer Solutions. 7. Solute and Solvent H/D Isotope Effects in Polystyrene−Propionitrile Solutions

(Liquid + liquid) equilibria of (polystyrene + nitroethane). Molecular weight, pressure, and isotope effects

Phase behavior of (polyacrylamides + water) solutions: concentration, pressure and isotope effects

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