Strengths and limitations of SAFT for calculating polar copolymer-solvent phase behavior

Hasch, Bruce M.; Lee, Sang-Ho; McHugh, Mark A.

doi:10.1002/(sici)1097-4628(19960214)59:7<1107::aid-app7>3.0.co;2-i

Cited by 38 publications

(43 citation statements)

References 3 publications

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“…The difficult issue in modeling SCF–polymer mixture behavior is to account for the intrasegmental and intersegmental interactions of the many segments of the polymer connected to a single backbone relative to the small number of segments in a solvent molecule. Approaches to modeling these systems are addressed elsewhere 39–41…”

Section: Resultsmentioning

confidence: 99%

Solubility of vinylidene fluoride polymers in supercritical CO2 and halogenated solvents

Dinoia

Conway

Lim³

et al. 2000

J. Polym. Sci. B Polym. Phys.

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The cloud‐point behaviors of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride‐co‐22 mol % hexafluoropropylene) (VDF–HFP22) are reported at temperatures up to 250 °C and pressures up to 3000 bar in supercritical CO2, CHF3, CH2F2, CHClF2, CClF3, CH3CHF2, CH2FCF3, CHF2CF3, and CH3CClF2. The molecular weight of PVDF has a smaller effect on the cloud point than the solvent quality. Cloud‐point pressures for both fluoropolymers decrease as the solvent polarizability, polar moment per molar volume, and density increases. However, it is extremely difficult to dissolve either fluoropolymer in CClF3, which has a large polarizability and a small dipole moment. CO2 is an effective solvent because it complexes with the CF dipole at low temperatures where energetic interactions fix the phase behavior. In addition, polymer architecture has a strong impact on the cloud‐point pressure. VDF–HFP22 has lower cloud‐point pressures than PVDF in all solvents because it has a larger free volume that promotes facile interactions between the solvent and the polymer segments. Cloud‐point data are also reported for amorphous poly(tetrafluoroethylene‐co‐x mol % 2,2‐bistrifluoromethyl‐4,5‐difluoro‐1,3‐dioxole) (TFE–PDDx ; x = 65 and 85) in CO2. These data provide an interesting comparison to the PVDF–CO2 and VDF–HFP22–CO2 systems because TFE–PDD65 and TFE–PDD87 have very high glass‐transition temperatures of 160 and 240 °C, respectively. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2832–2840, 2000

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Section: Resultsmentioning

confidence: 99%

Solubility of vinylidene fluoride polymers in supercritical CO2 and halogenated solvents

Dinoia

Conway

Lim³

et al. 2000

J. Polym. Sci. B Polym. Phys.

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“…The cloud point determines a complete dissolution of a polymer in the supercritical fluid. Lee and Mc Hugh 35 and Hasch et al 36 reported the phase behavior of poly(ethylene-co-methacrylic acid) and poly(ethylene-co-methyl acrylate) copolymers in DME.…”

Section: -27mentioning

confidence: 99%

A Faster Approach to Stereocomplex Formation of High Molecular Weight Polylactide Using Supercritical Dimethyl Ether

Bibi¹,

Jung²,

Lim³

et al. 2015

Polymer Korea

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Engineering the polylactide via stereocomplexation with supercritical fluid (SCF) technology paved way to fabricate polymers with enhanced thermal and mechanical properties. We aimed to establish a SCF medium with excellent solubility for PLA without any additional solvent/co-solvent. We, therefore, employed supercritical dimethyl ether to synthesize 100% stereocomplex polylactide from high molecular weight homopolymers with an excellent yield. The remarkable solubility of the homopolymers in dimethyl ether is the key for quick conversion to s-PLA. This study proves a rapid synthesis route of dry s-PLA powder with sc-DME at 250 bar, 70 o C and 1.5 h, which are reasonably achievable processing parameters compared to the conventional methods. The degree of stereocomplexation was evaluated under the effect of pressures, temperatures, times, homopolymer-concentrations and molecular weights. An increment in the degree of stereocomplexation was observed with increased temperature and pressure. Complete conversion to s-PLA was obtained for PLLA and PDLA with M n~2 00 kg·mol -1 with a total homopolymer to total DME ratio of 6:100% w/w at prescribed reaction conditions. The degree of stereocomplexation was determined by DSC and confirmed by XRD. Considerable improvement in thermo-mechanical properties of s-PLA was observed. DSC and TGA analyses proved a 50 o C enhancement in melting transition and a high onset temperature for thermal degradation of s-PLA respectively.

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“…5,15,16 The high-pressure equilibria of EMA-propylene, EMA-1-butene, and EMA-butane mixtures were investigated by Hasch et al 5 Cloud-point measurements for random copolymers with different amounts of methylacrylate (MA) repeat units are depicted in Figures 8-10. Compared with the phase behavior of LDPE-propylene, the demixing pressure at first declines when MA repeat units are added to the polymer chain (see 25 mass % of MA, Figure 8).…”

Section: Poly(ethylene-co-methyl Acrylate) Systemsmentioning

confidence: 99%

“…Such a model needs to be suitable for the entire range of repeat-unit composition and it should be suitable for extrapolations within. Earlier contributions toward this goal are manifold, for example, Song et al, 3 Gupta and Prausnitz, 4 and Hasch et al 5 In a previous study, the authors have proposed the perturbed-chain SAFT (PC-SAFT) equation of state. 6 The three pure-component parameters required for nonassociating molecules were determined for numerous substances.…”

Section: Introductionmentioning

confidence: 99%

Modeling Copolymer Systems Using the Perturbed-Chain SAFT Equation of State

Groß

Spuhl

Tumakaka

et al. 2003

Ind. Eng. Chem. Res.

197

221

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The perturbed-chain SAFT equation of state is extended to heterosegmented molecules and is applied to copolymers with a well-defined (alternating) repeat-unit sequence as well as to systems with a statistical sequence of the monomers in the backbone. Copolymers with a statistical sequence of the constituting repeat units usually require an assumption on the sequence of neighboring repeat units within the chain. A simple approach for defining such repeat-unit arrangements is proposed. Systems containing polyolefine copolymers (poly(ethylene-co-propylene) and poly(ethylene-co-1-butene)) covering the complete range of copolymer composition (including both of the appropriate homopolymers) were modeled in a mixture with solvents. Good results were found for mixtures of copolymer/solvent systems using constant interaction parameters. Copolymers comprising both nonpolar and polar repeat units, for example, poly-(ethylene-co-vinyl acetate) and poly(ethylene-co-methyl acrylate), require an interaction parameter correcting the interactions between repeat units of different types, which depends on the repeat-unit composition.

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Strengths and limitations of SAFT for calculating polar copolymer-solvent phase behavior

Cited by 38 publications

References 3 publications

Solubility of vinylidene fluoride polymers in supercritical CO2 and halogenated solvents

Solubility of vinylidene fluoride polymers in supercritical CO2 and halogenated solvents

A Faster Approach to Stereocomplex Formation of High Molecular Weight Polylactide Using Supercritical Dimethyl Ether

Modeling Copolymer Systems Using the Perturbed-Chain SAFT Equation of State

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