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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...

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Autores principales: Ahmad, Mohd Zamidi, Pelletier, Henri, Martin-Gil, Violeta, Castro-Muñoz, Roberto, Fila, Vlastimil
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
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%).
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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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