CO2 Gas Sorption Properties in Single-Phase and Phase-Separated Polystyrene/Poly(vinylmethylether) Blends

Hachisuka, Hisao; Sato, Takanori; Tsujita, Yoshiharu; Takizawa, Akira; Kinoshita, Takatoshi

doi:10.1295/polymj.21.417

Cited by 9 publications

(8 citation statements)

References 16 publications

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“…18 D 0 and DH also increased by pressure conditioning as well as CH'· The increase of DH was larger than that of 1024 D 0 . This may be attributed to increase of unrelaxed volume caused by pressure conditioning.…”

Section: Permeation Propertiesmentioning

confidence: 79%

“…Tg of the film was lowered markedly by plasticization at 60 atm of CO 2 as compared with that of unplasticized film. 18 The Tg of the film at 60 atm was below 25°C and thus the film was plasticized markedly by CO 2 and was in a liquid state at 60 atm. The decrease of Tg was depressed with increasing imide content, corresponding to the rigidity of segment.…”

Section: Resultsmentioning

confidence: 98%

“…As expected, CH' of PAA film increased by pressure conditioning. However, the other parameters, 18 and PI film. 6 The closed circles are experimental data and solid line corresponds to calculated curve based on the dual-mode sorption model (eq I).…”

Section: Sorption Propertiesmentioning

confidence: 93%

“…18 Various imidized PAA films were pressure conditioned as follows: PAA films of various imide content were exposed to a fixed pressure of CO 2 at 25°C for 12 h and cooled relatively quickly to liquid N 2 temperature under the pressure. The pressure was reduced at liquid N 2 temperature to keep plasticized structure of various imidized PAA films.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, the effect of pressure conditioning on sorption behavior was examined by CH' of dual-mode sorption parameters. The sorption parameters pressure conditioned ( O) are shown as the function of imide content as compared with unconditioned PAA film (e) 18 in Figure 5. The change in the CO 2 sorption amount in Figure 4 can be represented by variation in CH' of dual-mode sorption parameters.…”

Section: Sorption Propertiesmentioning

confidence: 99%

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Influence of Pressure Conditioning on the Gas Transport Properties of Imidized Polyamic Acid Films

Hachisuka

Tsujita

Takizawa

et al. 1989

Polym J

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ABSTRACT:The influence of pressure conditioning on the gas transport properties of various imidized polyamic acid [PAA] films was investigated. The variation of sorption and permeation caused by CO2 pressure conditioning was interpreted using dual-mode sorption and partial immobilization models. The sorption amount of CO2 at 25"C of unimidized PAA film increased markedly by pressure conditioning above 30atm of CO2 • It was found that unimidized PAA film was plasticized at 25' C at a pressure above 30 atm of CO2 and the film cooled relatively quickly to liquid N2 temperature and possibly contain a frozen microvoid or free volume between polymer segments. The sorption amount of CO2 of imidized PAA films also increased by pressure conditioning at 60 atm of CO2• This can be attributed to increase of unrelaxed volume due to pressure conditioning as shown by increase of Langmuir sorption capacity CH'· The increase in CH' of pressure conditioned films with low imide content was larger than that with high content. T.he diffusion coefficients of Henry and Langmuir modes of CO2 for imidized PAA film, D0 and DH, also increased by pressure conditoning. The increase of DH of each imidized PAA film was more marked than that of D0 • KEY WORDS Sorption / Diffusion / Polyamic Acid / Imidization / CO2 / Plasticization / Pressure Conditioning/ Langmuir Sorption Capacity Term/ It is well-known that sorption and permeation of gases in glassy polymer films are quite different from those in rubbery polymer films. This difference can be attributed to the fact that glassy polymers have unrelaxed volume or microvoid frozen in nonequilibrium state between segments. In general, the transport properties of glassy polymers have been analyzed on the basis of the dual-mode sorption 1 ·2 and partial immobilization models. 3 We reported that the nonequilibrium state varied by "thermal conditioning", e.g., quenching from above the glass transition temperature (Tg) or sub-Tg annealing. 4 -7 It was found that gas transport properties were influenced by nonequilibrium nature. Namely, gas solubility and diffusivity were enhanced by quenching from above Tg and decreased by sub-Tg annealing, reflecting that unrelaxed volume varies by thermal conditioning.

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Section: Permeation Propertiesmentioning

confidence: 79%

Section: Resultsmentioning

confidence: 98%

Section: Sorption Propertiesmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Section: Sorption Propertiesmentioning

confidence: 99%

See 3 more Smart Citations

Influence of Pressure Conditioning on the Gas Transport Properties of Imidized Polyamic Acid Films

Hachisuka

Tsujita

Takizawa

et al. 1989

Polym J

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Thermodynamics and Kinetic Processes of Polymer Blends and Block Copolymers in the Presence of Pressurized Carbon Dioxide

2008

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Environmentally‐responsible materials processing is becoming an important global consideration in a wide variety of technologies, especially those wherein volatile and/or residual organic solvents cannot be tolerated. In this context, polymer processing has benefited tremendously from advances achieved using high‐pressure CO2 as a viscosity modifier, plasticizing agent, foaming agent, and reaction medium. Pressurized CO2 is environmentally benign, inexpensive, sustainable, and versatile owing to its gas‐like viscosity and liquid‐like solubility, which can be tuned through judicious choice of temperature and pressure. The addition of high‐pressure CO2 to homopolymer blends and block copolymers can have a profound impact on polymer thermodynamics and kinetic processes since the number of interacting species increases. As a result, the compressibility as well as plasticization and intermolecular screening effects become non‐negligible. In this work, we review how these factors influence such polymeric systems, and discuss commercial polymer processes and applications that benefit from the use of high‐pressure CO2.

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Statistical mechanics of “dual‐mode” sorption in polyimides

Silverman

1993

J of Applied Polymer Sci

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A statistical mechanical description of the gas takeup or sorption in polyimides below their glass transition temperature is proposed. The model treated is formally similar to Fowler's early model of monolayer adsorption of gases on solid surfaces. It is expected to be appropriate for polymers exhibiting a significant degree of crystallization, e.g., the aromatic polyimides at temperatures well below their glass transition temperature. The model assumes that the penetrant gas molecules bind to a spectrum of states characterized by a distribution of binding energies. If it is assumed that the penetrant molecules bind to the polymer with only two well‐defined interaction energies, namely, zero as well as some particular finite value, a “dual‐mode” expression for sorption is obtained. It is pointed out that this “dual‐mode” or “two‐state” model is not consistent with some recent data obtained on carbon dioxide sorption in a polyimide. Two other simplified models are examined, a “uniform‐density‐of‐states” model and a “three‐state” model. The present treatment yields explicit expressions for the temperature dependence of the sorption parameters. This dependence reflects the thermodynamic redistribution of penetrant molecules among the available fixed density‐of‐states as the temperature is varied. It is pointed out that the temperature dependence of the Langmuir capacity constant obtained from nonlinear least squares fitting the standard “dual‐mode” sorption expression to the polyimide sorption data may lead to an erroneous inference concerning the decrease in “unrelaxed volume” as the temperature is increased from well below the glass transition temperature of the polymer. The “three‐state” model yields sorption isotherms that parallel the data of Sada et al. closely. This suggests the presence of multiple carbon dioxide binding sites in the polyimide. © 1993 John Wiley & Sons, Inc.

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CO2 Gas Sorption Properties in Single-Phase and Phase-Separated Polystyrene/Poly(vinylmethylether) Blends

Cited by 9 publications

References 16 publications

Influence of Pressure Conditioning on the Gas Transport Properties of Imidized Polyamic Acid Films

Influence of Pressure Conditioning on the Gas Transport Properties of Imidized Polyamic Acid Films

Thermodynamics and Kinetic Processes of Polymer Blends and Block Copolymers in the Presence of Pressurized Carbon Dioxide

Statistical mechanics of “dual‐mode” sorption in polyimides

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