Synthesis and characterization of polybenzimidazole membranes for gas separation with improved gas permeability: A grafting and blending approach
| Autor: | Melanie M. Merrick, Shreya Roy Choudhury, J. S. Riffle, John J. Lesko, Ran Liu, Joshua D. Moon, A.C. Fraser, Benny D. Freeman, Ronald M. Joseph |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Membrane permeability Ethylene oxide Filtration and Separation 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Biochemistry 0104 chemical sciences chemistry.chemical_compound Membrane chemistry Chemical engineering Permeability (electromagnetism) Propylene carbonate General Materials Science Thermal stability Gas separation Physical and Theoretical Chemistry 0210 nano-technology Syngas |
| Zdroj: | Journal of Membrane Science. 564:587-597 |
| ISSN: | 0376-7388 |
| DOI: | 10.1016/j.memsci.2018.07.064 |
| Popis: | Polybenzimidazoles (PBIs) are promising materials for gas separation membranes at elevated temperatures due to their excellent chemical and thermal stability and high Tgs. Their properties make them useful for gas separation of H2 and CO2 from pre-combustion syngas, which requires operating temperatures of 150–300 °C. PBIs have inherently low gas permeabilities, and thus the focus of this work was to improve permeability without sacrificing selectivity or mechanical properties of the membranes. Low molecular weight poly(ethylene oxide) (PEO) or poly(propylene carbonate) (PPC) were incorporated as thermally labile grafts and blends. It was believed that removing these low molecular weight sacrificial components via a controlled heat treatment would allow formation of “nanovoids” in the membrane that could increase the permeabilities. Gas transport for blends of PBI with 7 and 11 wt% of PPC and a PBI-g-PEO copolymer with 13 wt% of PEO were measured before and after heat treatment. Unlike other methods of increasing membrane permeability which results in a selectivity trade-off, heat treatment of these PBI blends and graft copolymers resulted in increases in both H2 permeability and H2/CO2 selectivity. The PBI-PPC blend containing 7 wt% of PPC, after heating at 350 °C, maintained most of the toughness of the PBI homopolymer. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect