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Storage Stability of 6FDA-DMB Polyamic Acid Solution Detected by Gel Permeation Chromatography Coupled with Multiple Detectors
Polyamic acid (PAA) is the precursor of polyimide (PI), and its solution’s properties have a direct influence on the final performances of PI resins, films, or fibers. The viscosity loss of a PAA solution over time is notorious. A stability evaluation and revelation of the degradation mechanism of P...
Autores principales: | , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10056122/ https://www.ncbi.nlm.nih.gov/pubmed/36987141 http://dx.doi.org/10.3390/polym15061360 |
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author | Hong, Mei Liu, Wei Gao, Runxiang Li, Rui Liu, Yonggang Dai, Xuemin Kang, Yu Qiu, Xuepeng Pan, Yanxiong Ji, Xiangling |
author_facet | Hong, Mei Liu, Wei Gao, Runxiang Li, Rui Liu, Yonggang Dai, Xuemin Kang, Yu Qiu, Xuepeng Pan, Yanxiong Ji, Xiangling |
author_sort | Hong, Mei |
collection | PubMed |
description | Polyamic acid (PAA) is the precursor of polyimide (PI), and its solution’s properties have a direct influence on the final performances of PI resins, films, or fibers. The viscosity loss of a PAA solution over time is notorious. A stability evaluation and revelation of the degradation mechanism of PAA in a solution based on variations of molecular parameters other than viscosity with storage time is necessary. In this study, a PAA solution was prepared through the polycondensation of 4,4′-(hexafluoroisopropene) diphthalic anhydride (6FDA) and 4,4′-diamino-2,2′-dimethylbiphenyl (DMB) in DMAc. The stability of a PAA solution stored at different temperatures (−18, −12, 4, and 25 °C) and different concentrations (12 wt% and 0.15 wt%) was systematically investigated by measuring the molecular parameters, including M(w), M(n), M(w)/M(n), R(g), and [η], using gel permeation chromatography coupled with multiple detectors (GPC-RI-MALLS-VIS) in a mobile phase 0.02 M LiBr/0.20 M HAc/DMF. The stability of PAA in a concentrated solution decreased, as shown by the reduction ratio of M(w) from 0%, 7.2%, and 34.7% to 83.8% and that of M(n) from 0%, 4.7%, and 30.0% to 82.4% with an increase of temperature from −18, −12, and 4 to 25 °C, respectively, after storage for 139 days. The hydrolysis of PAA in a concentrated solution was accelerated at high temperatures. Notably, at 25 °C, the diluted solution was much less stable than the concentrated one and exhibited an almost linear degradation rate within 10 h. The M(w) and M(n) decreased rapidly by 52.8% and 48.7%, respectively, within 10 h. Such faster degradation was caused by a greater water ratio and less entanglement of chains in the diluted solution. The degradation of (6FDA-DMB) PAA in this study did not follow the chain length equilibration mechanism reported in literature, given that both M(w) and M(n) declined simultaneously during storage. |
format | Online Article Text |
id | pubmed-10056122 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-100561222023-03-30 Storage Stability of 6FDA-DMB Polyamic Acid Solution Detected by Gel Permeation Chromatography Coupled with Multiple Detectors Hong, Mei Liu, Wei Gao, Runxiang Li, Rui Liu, Yonggang Dai, Xuemin Kang, Yu Qiu, Xuepeng Pan, Yanxiong Ji, Xiangling Polymers (Basel) Article Polyamic acid (PAA) is the precursor of polyimide (PI), and its solution’s properties have a direct influence on the final performances of PI resins, films, or fibers. The viscosity loss of a PAA solution over time is notorious. A stability evaluation and revelation of the degradation mechanism of PAA in a solution based on variations of molecular parameters other than viscosity with storage time is necessary. In this study, a PAA solution was prepared through the polycondensation of 4,4′-(hexafluoroisopropene) diphthalic anhydride (6FDA) and 4,4′-diamino-2,2′-dimethylbiphenyl (DMB) in DMAc. The stability of a PAA solution stored at different temperatures (−18, −12, 4, and 25 °C) and different concentrations (12 wt% and 0.15 wt%) was systematically investigated by measuring the molecular parameters, including M(w), M(n), M(w)/M(n), R(g), and [η], using gel permeation chromatography coupled with multiple detectors (GPC-RI-MALLS-VIS) in a mobile phase 0.02 M LiBr/0.20 M HAc/DMF. The stability of PAA in a concentrated solution decreased, as shown by the reduction ratio of M(w) from 0%, 7.2%, and 34.7% to 83.8% and that of M(n) from 0%, 4.7%, and 30.0% to 82.4% with an increase of temperature from −18, −12, and 4 to 25 °C, respectively, after storage for 139 days. The hydrolysis of PAA in a concentrated solution was accelerated at high temperatures. Notably, at 25 °C, the diluted solution was much less stable than the concentrated one and exhibited an almost linear degradation rate within 10 h. The M(w) and M(n) decreased rapidly by 52.8% and 48.7%, respectively, within 10 h. Such faster degradation was caused by a greater water ratio and less entanglement of chains in the diluted solution. The degradation of (6FDA-DMB) PAA in this study did not follow the chain length equilibration mechanism reported in literature, given that both M(w) and M(n) declined simultaneously during storage. MDPI 2023-03-09 /pmc/articles/PMC10056122/ /pubmed/36987141 http://dx.doi.org/10.3390/polym15061360 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/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 (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Hong, Mei Liu, Wei Gao, Runxiang Li, Rui Liu, Yonggang Dai, Xuemin Kang, Yu Qiu, Xuepeng Pan, Yanxiong Ji, Xiangling Storage Stability of 6FDA-DMB Polyamic Acid Solution Detected by Gel Permeation Chromatography Coupled with Multiple Detectors |
title | Storage Stability of 6FDA-DMB Polyamic Acid Solution Detected by Gel Permeation Chromatography Coupled with Multiple Detectors |
title_full | Storage Stability of 6FDA-DMB Polyamic Acid Solution Detected by Gel Permeation Chromatography Coupled with Multiple Detectors |
title_fullStr | Storage Stability of 6FDA-DMB Polyamic Acid Solution Detected by Gel Permeation Chromatography Coupled with Multiple Detectors |
title_full_unstemmed | Storage Stability of 6FDA-DMB Polyamic Acid Solution Detected by Gel Permeation Chromatography Coupled with Multiple Detectors |
title_short | Storage Stability of 6FDA-DMB Polyamic Acid Solution Detected by Gel Permeation Chromatography Coupled with Multiple Detectors |
title_sort | storage stability of 6fda-dmb polyamic acid solution detected by gel permeation chromatography coupled with multiple detectors |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10056122/ https://www.ncbi.nlm.nih.gov/pubmed/36987141 http://dx.doi.org/10.3390/polym15061360 |
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