Effect of fractional free volume andTg on gas separation through membranes made with different glassy polymers

2007 ◽  
Vol 107 (2) ◽  
pp. 1039-1046 ◽  
Author(s):  
Roberto Recio ◽  
Ángel E. Lozano ◽  
Pedro Prádanos ◽  
Ángel Marcos ◽  
Fernando Tejerina ◽  
...  
Keyword(s):  
Free Volume ◽  
Gas Separation ◽  
Glassy Polymers ◽  
Fractional Free Volume

Post-synthetic modification of CARDO-based materials: application in sour natural gas separation

2020 ◽  
Vol 8 (44) ◽  
pp. 23354-23367
Author(s):  
Ali Hayek ◽  
Abdulkarim Alsamah ◽  
Garba O. Yahaya ◽  
Eyad A. Qasem ◽  
Rashed H. Alhajry
Keyword(s):  
Natural Gas ◽  
Chemical Modification ◽  
Free Volume ◽  
Gas Separation ◽  
Polymeric Membrane ◽  
Fractional Free Volume ◽  
Gas Molecule

Chemical modification enhances gas molecule permeation through polymeric membrane matrices by increasing the fractional free volume.

scholarly journals “All Polyimide” Mixed Matrix Membranes for High Performance Gas Separation

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1329
Author(s):  
Maijun Li ◽  
Zhibo Zheng ◽  
Zhiguang Zhang ◽  
Nanwen Li ◽  
Siwei Liu ◽  
...  
Keyword(s):  
Free Volume ◽  
Gas Separation ◽  
Network Architecture ◽  
Mixed Matrix Membranes ◽  
High Porosity ◽  
Mixed Matrix ◽  
Fractional Free Volume ◽  
Interfacial Compatibility ◽  
Polyimide Matrix ◽  
Matrix Membranes

To improve the interfacial compatibility of mixed matrix membranes (MMMs) for gas separation, microporous polyimide particle (AP) was designed, synthesized, and introduced into intrinsic microporous polyimide matrix (6FDA-Durene) to form “all polyimide” MMMs. The AP fillers showed the feature of thermal stability, similar density with polyimide matrix, high porosity, high fractional free volume, large microporous dimension, and interpenetrating network architecture. As expected, the excellent interfacial compatibility between 6FDA-Durene and AP without obvious agglomeration even at a high AP loading of 10 wt.% was observed. As a result, the CO2 permeability coefficient of MMM with AP loading as low as 5 wt.% reaches up to 1291.13 Barrer, which is 2.58 times that of the pristine 6FDA-Durene membrane without the significant sacrificing of ideal selectivity of CO2/CH4. The improvement of permeability properties is much better than that of the previously reported MMMs, where high filler content is required to achieve a high permeability increase but usually leads to significant agglomeration or phase separation of fillers. It is believed that the excellent interfacial compatibility between the PI fillers and the PI matrix induce the effective utilization of porosity and free volume of AP fillers during gas transport. Thus, a higher diffusion coefficient of MMMs has been observed than that of the pristine PI membrane. Furthermore, the rigid polyimide fillers also result in the excellent anti-plasticization ability for CO2. The MMMs with a 10 wt.% AP loading shows a CO2 plasticization pressure of 300 psi.

scholarly journals Macromolecular design strategies toward tailoring free volume in glassy polymers for high performance gas separation membranes

2020 ◽  
Vol 5 (1) ◽  
pp. 22-48 ◽  
Author(s):  
Tanner Corrado ◽  
Ruilan Guo
Keyword(s):  
Free Volume ◽  
Gas Separation ◽  
High Performance ◽  
Glassy Polymers ◽  
Design Strategies ◽  
Separation Membranes ◽  
Gas Separation Membranes

This review highlights recently reported novel macromolecular design strategies providing tailorable free volume for high performance gas separation membranes.

Synthesis and characterization of triptycene-based polyimides with tunable high fractional free volume for gas separation membranes

2014 ◽  
Vol 2 (33) ◽  
pp. 13309-13320 ◽  
Author(s):  
Jennifer R. Wiegand ◽  
Zachary P. Smith ◽  
Qiang Liu ◽  
Christopher T. Patterson ◽  
Benny D. Freeman ◽  
...  
Keyword(s):  
Free Volume ◽  
Gas Separation ◽  
Gas Transport ◽  
Synthesis And Characterization ◽  
Fractional Free Volume ◽  
Separation Membranes ◽  
Gas Separation Membranes ◽  
Selective Separations ◽  
Polyimide Membranes

Triptycene-containing polyimide membranes with tunable fractional free volume promoting fast gas transport and selective separations.

scholarly journals Polyphenylsulfone (PPSU)-Based Copolymeric Membranes: Effects of Chemical Structure and Content on Gas Permeation and Separation

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2745
Author(s):  
Fan Feng ◽  
Can-Zeng Liang ◽  
Ji Wu ◽  
Martin Weber ◽  
Christian Maletzko ◽  
...  
Keyword(s):  
Free Volume ◽  
Gas Separation ◽  
Chemical Structure ◽  
Gas Permeability ◽  
Life Time ◽  
Gas Permeation ◽  
Polymer Chains ◽  
Polymer Materials ◽  
Fractional Free Volume ◽  
Trade Off

Although various polymer membrane materials have been applied to gas separation, there is a trade-off relationship between permeability and selectivity, limiting their wider applications. In this paper, the relationship between the gas permeation behavior of polyphenylsulfone(PPSU)-based materials and their chemical structure for gas separation has been systematically investigated. A PPSU homopolymer and three kinds of 3,3′,5,5′-tetramethyl-4,4′-biphenol (TMBP)-based polyphenylsulfone (TMPPSf) copolymers were synthesized by controlling the TMBP content. As the TMPPSf content increases, the inter-molecular chain distance (or d-spacing value) increases. Data from positron annihilation life-time spectroscopy (PALS) indicate the copolymer with a higher TMPPSf content has a larger fractional free volume (FFV). The logarithm of their O2, N2, CO2, and CH4 permeability was found to increase linearly with an increase in TMPPSf content but decrease linearly with increasing 1/FFV. The enhanced permeability results from the increases in both sorption coefficient and gas diffusivity of copolymers. Interestingly, the gas permeability increases while the selectivity stays stable due to the presence of methyl groups in TMPPSf, which not only increases the free volume but also rigidifies the polymer chains. This study may provide a new strategy to break the trade-off law and increase the permeability of polymer materials largely.

scholarly journals Molecule Dynamics Simulation of the Effect of Oxidative Aging on Properties of Nitrile Rubber

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 226
Author(s):  
Jinsong Yang ◽  
Weitao Lou
Keyword(s):  
Free Volume ◽  
Dynamic Properties ◽  
Compressive Strain ◽  
Mean Square Displacement ◽  
Nitrile Rubber ◽  
Dynamics Simulation ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Fractional Free Volume ◽  
Oxidative Aging

The effects of oxidative aging on the static and dynamic properties of nitrile rubber at the molecular scale were investigated by molecular dynamics simulation. The aged nitrile rubber models were constructed by introducing hydroxyl groups and carbonyl groups into rubber molecular chains to mimic oxidative aging. The static and dynamic properties of the unaged and aged nitrile rubber under different conditions were evaluated by mean square displacement, self-diffusion coefficients, hydrogen bond, fractional free volume, radial distribution function, cohesive energy density and solubility parameter. The results show that the elevated temperature intensified significantly the mobility of rubber molecular chains and fractional free volume, while the compressive strain displayed the opposite effect resulting in packing and rearrangement of rubber chains. The introduction of hydroxyl groups and carbonyl groups enhanced the polarity, intermolecular interactions, the volume and rigidity of molecular chains, implying weaker mobility of molecular chains as compared to unaged models. The compressive strain and oxidative aging both decreased the fractional free volume, which inhibited gaseous and liquid diffusion into the rubber materials, and slowed down the oxidative aging rate. This study provides insights to better understand the effect of molecular changes due to oxidative aging on the structural and dynamic properties of rubber materials at the molecular level.

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