Gas Permeation Properties of Soluble Aromatic Polyimides Based on 4-Fluoro-4,4'-Diaminotriphenylmethane
| Autor: | Alberto Galicia-Aguilar, F.A. Ruiz-Treviño, Jorge Froylan Palomeque-Santiago, Diego Guzmán-Lucero, Carla Aguilar-Lugo, Javier Guzmán, Claudia Camacho-Zuniga |
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| Rok vydání: | 2015 |
| Předmět: |
Hydrogen
chemistry.chemical_element lcsh:Technology Article Polymer chemistry General Materials Science Thermal stability Solubility lcsh:Microscopy Pendant group lcsh:QC120-168.85 lcsh:QH201-278.5 lcsh:T Intermolecular force gas separation membranes Permeation Decomposition Membrane chemistry Chemical engineering lcsh:TA1-2040 lcsh:Descriptive and experimental mechanics lcsh:Electrical engineering. Electronics. Nuclear engineering polyimides lcsh:Engineering (General). Civil engineering (General) lcsh:TK1-9971 |
| Zdroj: | Materials Materials, Vol 8, Iss 4, Pp 1951-1965 (2015) Volume 8 Issue 4 Pages 1951-1965 |
| ISSN: | 1996-1944 |
| Popis: | A series of new organic polyimides were synthesized from 4-fluoro-4'4"-diaminotriphenylmethane and four different aromatic dianhydrides through a one-step, high-temperature, direct polycondensation in m-cresol at 180–200 °C, resulting in the formation of high-molecular-weight polyimides (inherent viscosities ~ 1.0–1.3 dL/g). All the resulting polyimides exhibited good thermal stability with initial decomposition temperatures above 434 °C, glass-transition temperatures between 285 and 316 °C, and good solubility in polar aprotic solvents. Wide-angle X-ray scattering data indicated that the polyimides were amorphous. Dense membranes were prepared by solution casting and solvent evaporation to evaluate their gas transport properties (permeability, diffusivity, and solubility coefficients) toward pure hydrogen, helium, oxygen, nitrogen, methane, and carbon dioxide gases. In general, the gas permeability was increased as both the fractional free volume and d-spacing were also increased. A good combination of permeability and selectivity was promoted efficiently by the bulky hexafluoroisopropylidene and 4-fluoro-phenyl groups introduced into the polyimides. The results indicate that the gas transport properties of these films depend on both the structure of the anhydride moiety, which controls the intrinsic intramolecular rigidity, and the 4-fluoro-phenyl pendant group, which disrupts the intermolecular packing. |
| Databáze: | OpenAIRE |
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