Carbon dioxide-poly(vinylidene fluoride) interactions at high pressure

Briscoe, B.J.; Lorge, O.; Wajs, Anna; Dang, P.

doi:10.1002/(sici)1099-0488(19980930)36:13<2435::aid-polb18>3.0.co;2-4

Cited by 51 publications

(66 citation statements)

References 25 publications

(45 reference statements)

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“…In the vicinity of 75°C, the shape of the swelling curve, is similar to that obtained using the ultrasonic/mercury method. 29 However, the LVDT data show higher dilation (3.9%, 75°C, 276 bar) than that reported previously (1.2%, 80°C, 300 bar). This may be a result of lower crystallinity in our PVDF samples.…”

Section: Resultsmentioning

confidence: 87%

Quantifying Plasticization and Melting Behavior of Poly(vinylidene fluoride) in Supercritical CO₂ Utilizing a Linear Variable Differential Transformer

2003

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Supercritical CO2 plasticization of semicrystalline poly(vinylidene fluoride) (PVDF) was investigated by measuring linear dilation as a function of temperature (75-130°C) and pressure (138-670 bar) using a linear variable differential transformer (LVDT). The robustness of the LVDT technique allows the study of CO2 plasticization at high temperatures (to Tm) and pressures. Experiments at constant temperature (varying pressure) and constant pressure (varying temperature) were performed. With constant temperature experiments below 100°C, dilation increased up to 414 bar, while at higher pressures, the change of dilation with pressure attenuated. At higher temperatures (g117°C), dilation increased almost linearly with pressure through the experimental range. Constant pressure experiments were carried out to assess the effect of CO 2 pressure on Tm. With increasing pressure, Tm decreased to a minimum of 135°C at 483 bar (∆Tm ) 23°C). Above 483 bar, hydrostatic effects override plasticization and Tm increases. By comparing Tm under N2, a gas with minimal interaction with the polymer, competition between plasticization and hydrostatic pressure on Tm is clarified.

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Section: Resultsmentioning

confidence: 87%

Quantifying Plasticization and Melting Behavior of Poly(vinylidene fluoride) in Supercritical CO₂ Utilizing a Linear Variable Differential Transformer

2003

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“…Plasticization by the scCO 2 leads to increased free volume and chain mobility. 29 This argument, plus the micrographs of Figure 8, suggests that polymerization could continue inside the particles, if radicals were present and if the concentration of monomer were sufficiently high. A study to measure the partition coefficients for VF2 and DEPDC between the solid PVDF and the supercritical fluid is underway in our laboratory.…”

Section: Discussionmentioning

confidence: 99%

Continuous Precipitation Polymerization of Vinylidene Fluoride in Supercritical Carbon Dioxide: Modeling the Rate of Polymerization

Charpentier

DeSimone

Roberts

2000

Ind. Eng. Chem. Res.

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The kinetics of the surfactant-free precipitation polymerization of vinylidene fluoride (VF2) in supercritical carbon dioxide have been studied in a continuous stirred autoclave. Diethyl peroxydicarbonate was used as the free-radical initiator. The stirring rate and agitator design had no effect on the rate of polymerization (R p ) or on the weight-average molecular weight (M w ) of the formed poly(vinylidene fluoride) (PVDF). The fractional conversion of VF2 ranged from 7 to 26%, and R p was as high as 27 × 10 -5 mol/L‚s at 75°C and at a VF2 feed concentration of 2.5 mol/L. The PVDF polymer was collected as a dry, "free-flowing" powder and had M w 's up to 150 kg/mol and melt flow indices as low as 3.0 at 230°C. Homogeneous, free-radical kinetics provided a reasonable basis for describing the rate of polymerization, despite the heterogeneous nature of the system. The order of the reaction with respect to the monomer was found to be 1.0, and the order with respect to the initiator was 0.5. The experimental data suggest that an inhibitor is present in the monomer or that the monomer itself acts as an inhibitor.

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“…Nevertheless, the polymer is in the form of thin film and the adsorption phenomena (with regard to the absorption), which is not always representative of the industrial applications, is favoured. A second technique called "oscillating arm" allows to link the gas mass absorbed by the polymer, in the form of a block connected to the arm, with the oscillation frequency of this arm [25]. This method allows to reach high pressures and to use rather heavy samples of polymer.…”

Section: Sorption-desorptionmentioning

confidence: 99%

Transport Properties of Gases in Polymers: Experimental Methods

Flaconnèche

Martin

Klopffer

2001

Oil & Gas Science and Technology - Rev. IFP

110

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Résumé -Méthodes de mesure des coefficients de transport de gaz dans les polymères -La perméabilité aux gaz des polymères est une propriété inhérente à leur structure, qui résulte de la solubilisation des fluides dans la matière, puis de la diffusion de ces produits à travers la matrice polymère. L'aptitude d'un gaz à pouvoir traverser plus ou moins rapidement un matériau peut être mise à profit dans de nombreux domaines industriels. Des polymères très peu perméables sont par exemple recherchés dans des domaines aussi divers que la production pétrolière, l'emballage alimentaire ou le domaine automobile. Dans les applications pétrolières, la fonction principale des polymères est d'assurer l'étanchéité des structures telles que les conduites. Dans ce cas, les matériaux sont au contact de gaz à haute température et sous forte pression et les informations concernant les coefficients de transport dans ces conditions extrêmes ne sont généralement pas disponibles dans la littérature. C'est pourquoi certains appareillages susceptibles de donner accès à ces valeurs ont été développés. Après quelques rappels théoriques des méthodes de calcul pour l'obtention des coefficients de transport et une brève revue bibliographique des différentes techniques expérimentales existantes, les différents montages expérimentaux étudiés sont décrits précisément.Mots-clés : perméabilité, diffusion, solubilité, polymères, gaz, méthodes expérimentales. Abstract -Transport Properties of Gases in Polymers: Experimental Methods -The permeability of gases in polymers is a property inherent to their structure, which results, firstly, from the absorption of fluids by the material, then, from the diffusion of these products through the polymer matrix. The capacity of a gas to cross more or less fast a material can be used in numerous industrial

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Carbon dioxide-poly(vinylidene fluoride) interactions at high pressure

Cited by 51 publications

References 25 publications

Quantifying Plasticization and Melting Behavior of Poly(vinylidene fluoride) in Supercritical CO₂ Utilizing a Linear Variable Differential Transformer

Quantifying Plasticization and Melting Behavior of Poly(vinylidene fluoride) in Supercritical CO₂ Utilizing a Linear Variable Differential Transformer

Continuous Precipitation Polymerization of Vinylidene Fluoride in Supercritical Carbon Dioxide: Modeling the Rate of Polymerization

Transport Properties of Gases in Polymers: Experimental Methods

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Carbon dioxide-poly(vinylidene fluoride) interactions at high pressure

Cited by 51 publications

References 25 publications

Quantifying Plasticization and Melting Behavior of Poly(vinylidene fluoride) in Supercritical CO2 Utilizing a Linear Variable Differential Transformer

Quantifying Plasticization and Melting Behavior of Poly(vinylidene fluoride) in Supercritical CO2 Utilizing a Linear Variable Differential Transformer

Continuous Precipitation Polymerization of Vinylidene Fluoride in Supercritical Carbon Dioxide: Modeling the Rate of Polymerization

Transport Properties of Gases in Polymers: Experimental Methods

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Quantifying Plasticization and Melting Behavior of Poly(vinylidene fluoride) in Supercritical CO₂ Utilizing a Linear Variable Differential Transformer

Quantifying Plasticization and Melting Behavior of Poly(vinylidene fluoride) in Supercritical CO₂ Utilizing a Linear Variable Differential Transformer