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Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO(2)/CH(4) Separation
Chemical grafting or crosslinking of polyimide chains are known to be feasible approaches to increase polymer gas-pair selectivity and specific gas permeance. Different co-polyimides; 6FDA-ODA and 6FDA-ODA:DABA were synthesized using a two-step condensation method. Six different cross-linkers were u...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6161149/ https://www.ncbi.nlm.nih.gov/pubmed/30127269 http://dx.doi.org/10.3390/membranes8030067 |
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author | Ahmad, Mohd Zamidi Pelletier, Henri Martin-Gil, Violeta Castro-Muñoz, Roberto Fila, Vlastimil |
author_facet | Ahmad, Mohd Zamidi Pelletier, Henri Martin-Gil, Violeta Castro-Muñoz, Roberto Fila, Vlastimil |
author_sort | Ahmad, Mohd Zamidi |
collection | PubMed |
description | Chemical grafting or crosslinking of polyimide chains are known to be feasible approaches to increase polymer gas-pair selectivity and specific gas permeance. Different co-polyimides; 6FDA-ODA and 6FDA-ODA:DABA were synthesized using a two-step condensation method. Six different cross-linkers were used: (i) m-xylylene diamine; (ii) n-ethylamine; and (iii) n-butylamine, by reacting with 6FDA-ODA’s imide groups in a solid state crosslinking; while (iv) ethylene glycol monosalicylate (EGmSal); (v) ethylene glycol anhydrous (EGAn); and (vi) thermally labile iron (III) acetylacetonate (FeAc), by reacting with DABA carboxyl groups in 6FDA-ODA:DABA. The gas separation performances were evaluated by feeding an equimolar CO(2) and CH(4) binary mixture, at a constant feed pressure of 5 bar, at 25 °C. Fractional free volume (FFV) was calculated using Bondi’s contribution method by considering the membrane solid density property, measured by pycnometer. Other characterization techniques: thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) were performed accordingly. Depending on the type of amine, the CO(2)/CH(4) selectivity of 6FDA-ODA increased between 25 to 100% at the expense of CO(2) permeance. We observed the similar trend for 6FDA-ODA:DABA EGmSal-crosslinked with 143% selectivity enhancement. FeAc-crosslinked membranes showed an increment in both selectivity and CO(2) permeability by 126% and 29% respectively. Interestingly, FeAc acted as both cross-linker which reduces chain mobility; consequently improving the selectivity and as micro-pore former; thus increases the gas permeability. The separation stability was further evaluated using 25–75% CO(2) in the feed with CH(4) as the remaining, between 2 and 8 bar at 25 °C. We also observed no CO(2)-induced plasticization to the measured pressure with high CO(2) content (max. 75%). |
format | Online Article Text |
id | pubmed-6161149 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-61611492018-09-28 Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO(2)/CH(4) Separation Ahmad, Mohd Zamidi Pelletier, Henri Martin-Gil, Violeta Castro-Muñoz, Roberto Fila, Vlastimil Membranes (Basel) Article Chemical grafting or crosslinking of polyimide chains are known to be feasible approaches to increase polymer gas-pair selectivity and specific gas permeance. Different co-polyimides; 6FDA-ODA and 6FDA-ODA:DABA were synthesized using a two-step condensation method. Six different cross-linkers were used: (i) m-xylylene diamine; (ii) n-ethylamine; and (iii) n-butylamine, by reacting with 6FDA-ODA’s imide groups in a solid state crosslinking; while (iv) ethylene glycol monosalicylate (EGmSal); (v) ethylene glycol anhydrous (EGAn); and (vi) thermally labile iron (III) acetylacetonate (FeAc), by reacting with DABA carboxyl groups in 6FDA-ODA:DABA. The gas separation performances were evaluated by feeding an equimolar CO(2) and CH(4) binary mixture, at a constant feed pressure of 5 bar, at 25 °C. Fractional free volume (FFV) was calculated using Bondi’s contribution method by considering the membrane solid density property, measured by pycnometer. Other characterization techniques: thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) were performed accordingly. Depending on the type of amine, the CO(2)/CH(4) selectivity of 6FDA-ODA increased between 25 to 100% at the expense of CO(2) permeance. We observed the similar trend for 6FDA-ODA:DABA EGmSal-crosslinked with 143% selectivity enhancement. FeAc-crosslinked membranes showed an increment in both selectivity and CO(2) permeability by 126% and 29% respectively. Interestingly, FeAc acted as both cross-linker which reduces chain mobility; consequently improving the selectivity and as micro-pore former; thus increases the gas permeability. The separation stability was further evaluated using 25–75% CO(2) in the feed with CH(4) as the remaining, between 2 and 8 bar at 25 °C. We also observed no CO(2)-induced plasticization to the measured pressure with high CO(2) content (max. 75%). MDPI 2018-08-20 /pmc/articles/PMC6161149/ /pubmed/30127269 http://dx.doi.org/10.3390/membranes8030067 Text en © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Ahmad, Mohd Zamidi Pelletier, Henri Martin-Gil, Violeta Castro-Muñoz, Roberto Fila, Vlastimil Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO(2)/CH(4) Separation |
title | Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO(2)/CH(4) Separation |
title_full | Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO(2)/CH(4) Separation |
title_fullStr | Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO(2)/CH(4) Separation |
title_full_unstemmed | Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO(2)/CH(4) Separation |
title_short | Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO(2)/CH(4) Separation |
title_sort | chemical crosslinking of 6fda-oda and 6fda-oda:daba for improved co(2)/ch(4) separation |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6161149/ https://www.ncbi.nlm.nih.gov/pubmed/30127269 http://dx.doi.org/10.3390/membranes8030067 |
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