Polymeric Membrane Materials and Potential Use in Gas Separation

Park, Ho Bum; Lee, Young Moo

doi:10.1002/9780470276280.ch24

Cited by 21 publications

(7 citation statements)

References 77 publications

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“…(a) Gas permeation properties and (b) diffusion coefficients of TR-PBOs and highly permeable polymers (◼: tPBO ( 5a ); ●: aPBO ( 5b ); ▲: cPBO ( 5c ); ▼: sPBO ( 5d ); ◻: PTMSP; ○: AF 2400; ◇: PIM-1).…”

Section: Resultsmentioning

confidence: 99%

Thermally Rearranged (TR) Polybenzoxazole: Effects of Diverse Imidization Routes on Physical Properties and Gas Transport Behaviors

et al. 2010

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Conversion of hydroxyl-containing polyimides into polybenzoxazole can be achieved by thermal rearrangement of the aromatic polymer chain with decarboxylation at elevated temperature. Synthetic methods to prepare polyimide precursors are important for the resulting thermally rearranged (TR) polymer membranes. Here, we report on the effect of several imidization methods on the properties of TR polymer membranes. Thermal and chemical imidizations are the most common routes to prepare polyimides, and solution thermal imidization using an azeotrope is also widely used, especially to obtain soluble polyimide-containing functional groups. We report here on the syntheses of ortho-functional polyimides from 4,4′-hexafluoroisopropylidene diphthalic anhydrides and 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane by three different imidization methods. Acetate-containing polyimides by chemical imidization and further silylation treatment as well as hydroxyl-containing polyimides by thermal and azeotropic imidization are characterized using thermogravimetric analysis, density, positron annihilation lifetime spectroscopy, and gas permeation property measurements. Comparison between the precursor polyimides and the resulting thermally rearranged polybenzoxazole (TR-PBO) membranes exhibited significant increase in fractional free volumes and cavity sizes followed by enhanced gas permeation properties.

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Section: Resultsmentioning

confidence: 99%

Thermally Rearranged (TR) Polybenzoxazole: Effects of Diverse Imidization Routes on Physical Properties and Gas Transport Behaviors

et al. 2010

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“…In this case, there must be sufficient space between clay layers to allow for a penetrant to "prefer" these tortuous channels between clay layers. Moreover, oxygen molecules are known to have a kinetic diameter of 0.346 nm (64), so it would seem that they should always prefer the gaps between coplanar platelets over a path between clay layers. However, this consistent preference would suggest that the permeabilities shown in Table 1 should be very similar among all the films.…”

Section: Resultsmentioning

confidence: 99%

Transparent Clay−Polymer Nano Brick Wall Assemblies with Tailorable Oxygen Barrier

Priolo

Gamboa

Grunlan

2009

ACS Appl. Mater. Interfaces

218

262

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Thin films of sodium montmorillonite clay and branched polyethylenimine (PEI) are deposited on various substrates using layer-by-layer assembly. Films with 40 polymer-clay layers contain more than 84 wt% clay, have hardness as high as 1 GPa, and are completely transparent. Oxygen transmission rates (OTR) through these films decrease as the pH of PEI increases. These pH-tailorable properties are the result of changing PEI charge density, which causes the polymer to deposit more thickly at high pH because of low charge density. After 70 PEI (at pH 10)-clay layers are deposited onto 179 µm poly(ethylene terephthalate) film, the resulting 231 nm assembly has an OTR below the detection limit of commercial instrumentation (<0.005 cc/(m 2 day atm)). When multiplied by thickness, the resulting oxygen permeability is found to be less than 0.002 × 10 -6 cc/(m day atm)), which is lower than values typically reported for SiOx. This is the lowest permeability ever reported for a polymer-clay composite and is believed to be due to a brick wall nanostructure created by the alternate adsorption of polymeric mortar and highly oriented, exfoliated clay platelets. Because of their high level of transparency and gas barrier, these films are good candidates for a variety of flexible electronics, food, and pharmaceutical packaging.

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“…Helium has a very small kinetic diameter (0.260 nm), small critical volume (57.5 Å 3 ) and low condensability, with a critical temperature of 5.3 K. Oxygen (O 2 ) has higher kinetic diameter (0.364 nm), higher critical volume (73.5 Å 3 ) and much higher critical temperature (155 K) (data from [34]). Generally, increasing critical volume of a gas scales with decrease in the diffusion coefficient, while increasing critical temperature scales with increase in the solubility coefficient.…”

Section: Gas Barrier Propertiesmentioning

confidence: 99%

Impact of crystallinity of poly(lactide) on helium and oxygen barrier properties

Guinault¹,

Sollogoub²,

Ducruet³

et al. 2012

European Polymer Journal

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible.This is an author-deposited version published in: http://sam.ensam.eu Handle ID: .http://hdl.handle.net/10985/10118 To cite this version :A GUINAULT, C SOLLOGOUB, Violette DUCRUET, Sandra DOMENEK -Impact of crystallinity of poly(lactide) on helium and oxygen barrier properties -European Polymer Journal -Vol. 48, p.779-788 -2012 Any correspondence concerning this service should be sent to the repository The helium and oxygen gas barrier properties of poly(lactide) were investigated as a function of stereochemistry and crystallinity degree. Poly(L-lactide) and poly(D,L-lactide) films were obtained by extrusion and thermally cold crystallized in either a 0 -or a-crystalline form with increasing crystallinity degree. Annealing of the films at low temperatures yielded to a 0 -crystals as well as the creation of a rigid amorphous fraction in the amorphous phase. Unexpectedly, the quantity of the rigid amorphous fraction was highest in poly(L-lactide) crystallized under a 0 -form. Unexpectedly, the gas permeability increased with increasing quantity of a 0 -crystals in poly(L-lactide) and remained constant with increasing quantity of a 0 -crystals in poly(D,L-lactide). A gain in gas barrier properties was obtained upon crystallization at higher temperatures yielding a-crystals. The analysis of the oxygen transport parameters, in particular the diffusion and the solubility coefficient showed that the diffusion was accelerated upon crystallization, while the solubility coefficient decreased in an expected manner which led to conclude that it remained constant in the amorphous phase. The acceleration of the diffusion seems to be correlated to the occurrence of the rigid amorphous fraction, which holds larger free volume. To conclude, for optimization of poly(lactide) gas barrier properties by focussing on the decrease of the diffusion coefficient it can be suggested to work with poly(D,L-lactide) and to aim a crystallization in a-form avoiding the formation of a rigid amorphous fraction.

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Polymeric Membrane Materials and Potential Use in Gas Separation

Cited by 21 publications

References 77 publications

Thermally Rearranged (TR) Polybenzoxazole: Effects of Diverse Imidization Routes on Physical Properties and Gas Transport Behaviors

Thermally Rearranged (TR) Polybenzoxazole: Effects of Diverse Imidization Routes on Physical Properties and Gas Transport Behaviors

Transparent Clay−Polymer Nano Brick Wall Assemblies with Tailorable Oxygen Barrier

Impact of crystallinity of poly(lactide) on helium and oxygen barrier properties

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