High-pressure viscosity of polystyrene solutions in toluene + carbon dioxide binary mixtures

Yeo, Sang-Do; Kiran, Erdoǧan

doi:10.1002/(sici)1097-4628(20000110)75:2<306::aid-app13>3.0.co;2-s

Cited by 16 publications

(19 citation statements)

References 19 publications

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“…The falling-weight viscometer has been used extensively in the past for the determination of viscosities in systems under high pressure [9,14,17,[19][20][21][22][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. The falling-weight viscometer is relatively simple in construction, is easily adaptable for highpressure applications and typically exhibits high repeatability and accuracy.…”

Section: Viscometer Designmentioning

confidence: 85%

“…Assuming similar flow regimes within the annulus and concentric fall of the weight during calibration and subsequent viscosity determinations, correlations in the form of Eq. (2) have been widely used to determine the viscosity of other Newtonian fluids relative to the calibration fluids [9,17,20,22,29,39,[44][45][46][47][48].…”

Section: Calculation Methodsmentioning

confidence: 99%

“…Density had previously been reported to be a good scaling factor for the viscosity of polymer solutions [17,18,20]. The enhanced viscosity of a fluid with increasing density is consis- Fig.…”

Section: Effect Of Liquid Densitymentioning

confidence: 99%

“…The viscosities of mixtures under supercritical conditions have also been recently investigated [9,[14][15][16][17][18][19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Viscosity measurements on gas expanded liquid systems—Methanol and carbon dioxide

Sih

Dehghani

Foster

2007

The Journal of Supercritical Fluids

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Section: Viscometer Designmentioning

confidence: 85%

Section: Calculation Methodsmentioning

confidence: 99%

Section: Effect Of Liquid Densitymentioning

confidence: 99%

“…The viscosities of mixtures under supercritical conditions have also been recently investigated [9,[14][15][16][17][18][19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

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Viscosity measurements on gas expanded liquid systems—Methanol and carbon dioxide

Sih

Dehghani

Foster

2007

The Journal of Supercritical Fluids

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“…4,5 For the purpose of industrial processing, the dependence of viscosity on temperature, pressure, and solvent composition was investigated for polymer + organic solvent + supercritical CO 2 systems. 6,7 Most of these studies are, however, limited to rather high polymer concentrations (above 1 wt %) and fixed molecular weights M, and none of them discusses the effect of polymer chain dimensions or related molecular properties on ; of polymer solutions increases with increasing chain dimensions.…”

mentioning

confidence: 99%

Intrinsic Viscosity of Polystyrene in Toluene-Supercritical Carbon Dioxide Mixtures

2009

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Intrinsic viscosities [] were determined for five polystyrene samples ranging in molecular weight M w from 9:0 Â 10 4 to 1:2 Â 10 6 in toluene-supercritical carbon dioxide mixtures with different weight fractions of CO 2 (denoted as w(CO 2 )) at 40 C in a pressure range P ¼ 7:0{10:0 MPa using a rolling-ball viscometer. For every sample [] was a gradually increasing function of P, indicating that the polystyrene coil expands with increasing P. At fixed P and w(CO 2 ), the molecular weight dependence of [] was expressed in the form ½ / M w a . The exponent a remarkably changed with w(CO 2 ) at constant P; for example, it decreased from 0.68 (a good solvent value) to 0.42 (a poor solvent value below the theta point where a ¼ 0:5) with an increase in w(CO 2 ) from 15 to 31% at P ¼ 7:0 MPa. The solvent goodness was quantified in terms of the binarycluster integral determined by analyzing the [] data according to the two-parameter theory.KEY WORDS: Intrinsic Viscosity / High Pressure / Supercritical Liquid / Carbon Dioxide / Excluded-Volume Effect / Binary-Cluster Integral / Supercritical carbon dioxide (critical temperature 31.1 C and pressure 7.38 MPa) is known to be compatible with many organic solvents. Such mixtures, in which polymer solubility is controllable by changing the pressure and the solvent composition, 1-3 have possible applications to separation or blending of chemically different polymers and molecular weight fractionation of homopolymers. 4,5 For the purpose of industrial processing, the dependence of viscosity on temperature, pressure, and solvent composition was investigated for polymer + organic solvent + supercritical CO 2 systems.6,7 Most of these studies are, however, limited to rather high polymer concentrations (above 1 wt %) and fixed molecular weights M, and none of them discusses the effect of polymer chain dimensions or related molecular properties on ; of polymer solutions increases with increasing chain dimensions.The intrinsic viscosity [] of a polymer coil (i.e., a long flexible chain) is a basic molecular property related closely to the chain dimensions. It increases with an increase in M or solvent power (i.e., the strength of intramolecular excluded volume in a term of polymer statistical mechanics), but such dependence of [] in an organic solvent containing supercritical CO 2 has not been explored despite the importance to our understanding of the effect of supercritical CO 2 on polymer solution properties.In the present work, we determine [] for polystyrene (PS) samples in toluene-supercritical CO 2 mixtures as functions of molecular weight, solvent composition, and pressure higher than the boundary between one liquid phase and liquid-gas two phase regions. 4 The relation between the extent of chain expansion and the solvent condition is discussed on the basis of excluded-volume theories.8

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Viscosity of polystyrene solutions expanded with carbon dioxide

Whittier

Zanten

et al. 2005

J of Applied Polymer Sci

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ABSTRACT:The viscosity of solutions of polystyrene (PS) in decahydronaphthalene (DHN) was measured in the presence of carbon dioxide (CO 2 ) with a moving-piston viscometer. The effects of the CO 2 pressure (0 -21 MPa), polymer concentration (1-15 wt %), temperature (306 -423 K), and polymer molecular weight (126 and 412 kDa) on the viscosity were investigated. In the absence of CO 2 , the increase in the viscosity with increasing polymer concentration was approximately exponential in concentration and was well described by the Martin equation. All the data fell on a single line when the relative viscosity was plotted against cM 0.50 (where c is the concentration of the polymer in solution and M is the molecular weight of the polymer). The viscosity of the polymer solution decreased with increasing CO 2 pressure under otherwise constant conditions. For a given CO 2 pressure, the viscosity reduction was greatest when the relative viscosity was high in the absence of CO 2 , that is, for high-molecular-weight polymer, high polymer concentrations, and low temperatures. Reductions in the relative viscosity of almost 2 orders of magnitude were observed in some cases. The viscosity of solutions of PS in DHN also was measured in the presence of sulfur hexafluoride (SF 6 ). At a given pressure, SF 6 was about as effective as CO 2 in reducing the solution viscosity.

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High-pressure viscosity of polystyrene solutions in toluene + carbon dioxide binary mixtures

Cited by 16 publications

References 19 publications

Viscosity measurements on gas expanded liquid systems—Methanol and carbon dioxide

Viscosity measurements on gas expanded liquid systems—Methanol and carbon dioxide

Intrinsic Viscosity of Polystyrene in Toluene-Supercritical Carbon Dioxide Mixtures

Viscosity of polystyrene solutions expanded with carbon dioxide

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