Gas transport properties of polyimide membranes based on triphenylamine unit

2016 ◽  
Vol 30 (1) ◽  
pp. 100-108 ◽  
Author(s):  
Guangliang Song ◽  
Lina Wang ◽  
Dandan Liu ◽  
Jianan Yao ◽  
Yiming Cao
Keyword(s):  
Transport Properties ◽  
Diffusion Coefficients ◽  
Gas Transport ◽  
Nitrogen Atmosphere ◽  
Gas Permeation ◽  
Gas Transport Properties ◽  
Thermal Imidization ◽  
Backbone Structure ◽  
Solubility Coefficients ◽  
Permeation Properties

A series of polyimide (PI) membranes were prepared based on three triphenylamine-based diamines, namely 4,4′-diaminotriphenylamine, 4,4′-diamino-3′′,5′′-dimethyltriphenylamine, and 4,4′-diamino-3′′,5′′-ditrifluoromethyltriphenylamine, via thermal imidization procedure. The PI membranes displayed good thermal properties, with glass transition temperatures of 279–341°C and 5% weight loss temperatures above 515°C under a nitrogen atmosphere. The gas permeation properties of the membranes were investigated and interpreted from the viewpoint of the PI backbone structure. The gas permeation coefficients increased as the substituent pendant groups at the 3′′,5′′ positions of the triphenylamine varied from –H to –CH3 and –CF3, and the permselectivity of gas pairs (including hydrogen/nitrogen (N2), oxygen/N2, carbon dioxide (CO2)/N2, and CO2/methane) decreased in this order. The diffusion coefficients and solubility coefficients were calculated, and the results revealed the variation of the substituted triphenylamine units principally influenced the diffusion coefficients, indicating that the substituted triphenylamine affected the gas transport properties by “diffusivity-controlled” modification.

Ion Beam Modification of Matrimid® Gas Separation Membrane—Evolution in Chemical Structure, Microstructure and Gas Permeation Properties

2002 ◽  
Vol 752 ◽  
Author(s):  
Xinglong Xu ◽  
Ling Hu ◽  
Maria Coleman
Keyword(s):  
Transport Properties ◽  
Chemical Structure ◽  
Gas Transport ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Gas Permeation ◽  
Ion Beam Modification ◽  
Gas Transport Properties ◽  
Wide Range ◽  
Permeation Properties

ABSTRACTMatrimid® is a widely used polyimide that has both attractive thermal and gas transport properties. In addition, it has been used as a precursor polymer for production of carbon molecular sieving membranes with commercially interesting gas separations. Ion beam irradiation over a wide range of doses was used to modify a series of Matrimid® membranes. A combined analysis of impact of ion irradiation on the chemical structure, microstructure and gas transport properties of Matrimid® will be presented. Specifically, the evolution in gas permeation properties following irradiation over a wide range of doses will be discussed. Ion irradiation resulted in combined increased permeability and permselectivity for several gas pairs of interest.

scholarly journals Enhancing Gas Permeation Properties of Pebax® 1657 Membranes via Polysorbate Nonionic Surfactants Doping

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 253 ◽  
Author(s):  
Paola Bernardo ◽  
Gabriele Clarizia
Keyword(s):  
Transport Properties ◽  
Nonionic Surfactants ◽  
Gas Transport ◽  
Carbon Oxide ◽  
Composite Membranes ◽  
Gas Permeation ◽  
Effect Of Temperature ◽  
Membrane Morphology ◽  
Gas Transport Properties ◽  
The One

Composite membranes were prepared by co-casting, incorporating two nonionic surfactants in a poly(ether-block-amide), Pebax® 1657 up to 50 wt %. These polysorbate nonionic surfactants contain many ethylene oxide units and are very CO2-philic agents; thereby, they can be exploited as membrane additives for gas separation involving carbon oxide. Dynamic light scattering analysis proved a higher stability of additionated Pebax® 1657 solutions with respect to those containing only the copolymer. Scanning electron microscopy showed a regular membrane morphology without pores or defects for all investigated samples. If on the one hand the addition of the additive has depressed the mechanical properties, on the other, it has positively influenced the gas transport properties of Pebax® 1657 films. CO2 permeability increased up to two or three times after the incorporation of 50 wt % additive in copolymer matrix, while the selectivity was not significantly affected. The effect of temperature on permanent gas transport properties was studied in the range of 15–55 °C.

Aromatic polyamides and copolyamides containing fluorene group

2017 ◽  
Vol 30 (7) ◽  
pp. 821-832 ◽  
Author(s):  
Tengyang Zhu ◽  
Xing Yang ◽  
Xiaoqi He ◽  
Yayun Zheng ◽  
Jujie Luo
Keyword(s):  
Transport Properties ◽  
Chemical Structure ◽  
Gas Transport ◽  
Gas Permeability ◽  
Operating Temperature ◽  
Gas Permeation ◽  
Proton Nuclear Magnetic Resonance ◽  
Fractional Free Volume ◽  
Aromatic Polyamides ◽  
Gas Transport Properties

A series of new aromatic polyamides (PAs) and copolyamides (CPAs) containing fluorene group have been synthesized through polycondensation reaction. The chemical structure was confirmed by Fourier transform infrared and proton nuclear magnetic resonance (1H NMR). PAs and CPAs exhibited the higher thermal stability ( Td15 > 378°C in nitrogen), the higher glass transition temperature ( Tg > 345°C), and excellent solubility in polar solvent. Gas transport properties of the PA and CPA membranes were investigated using different single gases (hydrogen (H2), carbon dioxide (CO2), oxygen (O2), methane (CH4), and nitrogen (N2)). We discussed the effect of chemical structure and operating temperature on gas transport properties. The results show that PA-1 containing a hexafluoroisopropylidene moiety exhibited the highest gas permeability ( PH2 = 12.71 Barrer, PCO2 = 12.26 Barrer, and PO2 = 2.62 Barrer) and reasonably good selectivity ( α(H2/N2) = 27.63, α(CO2/N2) = 26.65, and α(O2/N2) = 5.70) at 25°C and 1 atm. For all the membranes, gas permeability gradually increased with the increase in operating temperature, while the selectivity gradually decreased. These gas permeation results were well correlated with fractional free volume, interchain d-spacing ( dsp), and intermolecular interaction.

scholarly journals Synthesis and Gas Transport Properties of Addition Polynorbornene with Perfluorophenyl Side Groups

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1282
Author(s):  
Gleb O. Karpov ◽  
Ilya L. Borisov ◽  
Alexey V. Volkov ◽  
Eugene Sh. Finkelshtein ◽  
Maxim V. Bermeshev
Keyword(s):  
Transport Properties ◽  
Gas Transport ◽  
Synergetic Effect ◽  
Monomer Concentration ◽  
Polymeric Materials ◽  
Gas Permeation ◽  
Structure Property ◽  
Membrane Gas Separation ◽  
Gas Transport Properties ◽  
High Yields

Polynorbornenes represent a fruitful class of polymers for structure–property study. Recently, vinyl-addition polynorbornenes bearing side groups of different natures were observed to exhibit excellent gas permeation ability, along with attractive C4H10/CH4 and CO2/N2 separation selectivities. However, to date, the gas transport properties of fluorinated addition polynorbornenes have not been reported. Herein, we synthesized addition polynorbornene with fluoroorganic substituents and executed a study on the gas transport properties of the polymer for the first time. A norbornene-type monomer with a C6F5 group, 3-pentafluorophenyl-exo-tricyclononene-7, was successfully involved in addition polymerization, resulting in soluble, high-molecular-weight products obtained in good or high yields. By varying the monomer concentration and monomer/catalyst ratio, it was possible to reach Mw values of (2.93–4.35) × 105. The molecular structure was confirmed by NMR and FTIR analysis. The contact angle with distilled water revealed the hydrophobic nature of the synthesized polymer as expected due to the presence of fluoroorganic side groups. A study of the permeability of various gases (He, H2, O2, N2, CO2, and CH4) through the prepared polymer disclosed a synergetic effect, which was achieved by the presence of both bulky perfluorinated side groups and rigid saturated main chains. Addition poly(3-pentafluorophenyl-exo-tricyclononene-7) was more permeable than its metathesis analogue by a factor of 7–21, or the similar polymer with flexible main chains, poly(pentafluorostyrene), in relation to the gases tested. Therefore, this investigation opens the door to fluorinated addition polynorbornenes as new potential polymeric materials for membrane gas separation.

The Effect of the Type and Concentration of the Crosslinking Diene on the Gas Transport Properties of Membranes Based on Polyoctylmethylsiloxane

2020 ◽  
Vol 2 (6) ◽  
pp. 399-406
Author(s):  
E. A. Grushevenko ◽  
I. L. Borisov ◽  
D. S. Bakhtin ◽  
V. V. Volkov ◽  
A. V. Volkov
Keyword(s):  
Transport Properties ◽  
Gas Transport ◽  
Gas Transport Properties

New poly(ether imide)s with pendant di-tert-butyl groups: Synthesis, characterization and gas transport properties

2019 ◽  
Vol 217 ◽  
pp. 183-194 ◽  
Author(s):  
N. Belov ◽  
R. Chatterjee ◽  
R. Nikiforov ◽  
V. Ryzhikh ◽  
S. Bisoi ◽  
...  
Keyword(s):  
Transport Properties ◽  
Gas Transport ◽  
Tert Butyl ◽  
Gas Transport Properties

scholarly journals A Molecular Simulation Study of Silica/Polysulfone Mixed Matrix Membrane for Mixed Gas Separation

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2199
Author(s):  
Khadija Asif ◽  
Serene Sow Mun Lock ◽  
Syed Ali Ammar Taqvi ◽  
Norwahyu Jusoh ◽  
Chung Loong Yiin ◽  
...  
Keyword(s):  
Transport Properties ◽  
Molecular Simulation ◽  
Gas Separation ◽  
Membrane Separation ◽  
Gas Transport ◽  
Mixed Matrix ◽  
Mixed Gas ◽  
Gas Transport Properties ◽  
Simulation Results ◽  
Mixed Gases

Polysulfone-based mixed matrix membranes (MMMs) incorporated with silica nanoparticles are a new generation material under ongoing research and development for gas separation. However, the attributes of a better-performing MMM cannot be precisely studied under experimental conditions. Thus, it requires an atomistic scale study to elucidate the separation performance of silica/polysulfone MMMs. As most of the research work and empirical models for gas transport properties have been limited to pure gas, a computational framework for molecular simulation is required to study the mixed gas transport properties in silica/polysulfone MMMs to reflect real membrane separation. In this work, Monte Carlo (MC) and molecular dynamics (MD) simulations were employed to study the solubility and diffusivity of CO2/CH4 with varying gas concentrations (i.e., 30% CO2/CH4, 50% CO2/CH4, and 70% CO2/CH4) and silica content (i.e., 15–30 wt.%). The accuracy of the simulated structures was validated with published literature, followed by the study of the gas transport properties at 308.15 K and 1 atm. Simulation results concluded an increase in the free volume with an increasing weight percentage of silica. It was also found that pure gas consistently exhibited higher gas transport properties when compared to mixed gas conditions. The results also showed a competitive gas transport performance for mixed gases, which is more apparent when CO2 increases. In this context, an increment in the permeation was observed for mixed gas with increasing gas concentrations (i.e., 70% CO2/CH4 > 50% CO2/CH4 > 30% CO2/CH4). The diffusivity, solubility, and permeability of the mixed gases were consistently increasing until 25 wt.%, followed by a decrease for 30 wt.% of silica. An empirical model based on a parallel resistance approach was developed by incorporating mathematical formulations for solubility and permeability. The model results were compared with simulation results to quantify the effect of mixed gas transport, which showed an 18% and 15% percentage error for the permeability and solubility, respectively, in comparison to the simulation data. This study provides a basis for future understanding of MMMs using molecular simulations and modeling techniques for mixed gas conditions that demonstrate real membrane separation.

Gas transport properties of liquid crystalline poly(p-phenyleneterephthalamide)

1992 ◽  
Vol 25 (2) ◽  
pp. 788-796 ◽  
Author(s):  
D. H. Weinkauf ◽  
H. D. Kim ◽  
D. R. Paul
Keyword(s):  
Transport Properties ◽  
Liquid Crystalline ◽  
Gas Transport ◽  
Gas Transport Properties
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