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Versatile Recyclable Kevlar Nanofibrous Aerogels Enabled by Destabilizing Dynamic Balance Strategy

Versatile Recyclable Kevlar Nanofibrous Aerogels Enabled by Destabilizing Dynamic Balance Strategy Aerogels are of great interest in diverse fields including thermal insulation, environmental protection, liquid separation, electromagnetic shielding, etc. However, the development of renewable and recyclable aerogels, especially synthetic polymer-based ones, remains an enormous challenge, which seriously hinders the practical application of aerogels. Herein, utilizing Kevlar nanofibers (KNFs) as representative synthetic polymer building blocks, a destabilizing dynamic balance (DDB) strategy is proposed to fabricate recyclable aerogels with high reprocessing consistency. More specifically, aprotic esters (e.g., di-tert-butyl decarbonate, DiBoc) and alkalis (e.g., potassium tert-butoxide, t-BuOK) are introduced to trigger the destabilizing dynamic balance between deprotonation–protonation of KNFs, resulting in a reversible sol–gel transition. Meanwhile, the duration of sol–gel transition (i.e., gelation) time, adjustable from 10–2 to 103 min, is compatible with versatile processing methods, such as static mould casting, dynamic wet spinning, dynamic blade coating and dynamic 3D printing. These unique advantages enable the fabrication of various KNF aerogel products (i.e., continuous fibers, continuous films, large-sized monoliths and 3D-printed articles) with low density (33–165 mg/cm3), high compressive modulus (up to 52 MPa), high specific surface area (360–404 m2/g) and low thermal conductivity (0.027–0.050 W/m·K). Notably, these properties are comparable or superior to that of previously reported KNF aerogels and far superior to that of recyclable aerogels. Compared with direct fabrication from raw materials, the DDB strategy reduces the cost by 50.5% and 82.5% when products are made from recycled aerogels and wet gels, respectively. Such cost reduction further increases with the number of recycling cycles, which is calculated as $275 per kilogram KNF aerogel with 5 cycles. This work develops extraordinary KNF aerogels those can be recycled and reused, as well as provides a strategy that can be applied to design more recyclable aerogels.Graphical Abstract[graphic not available: see fulltext] http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Advanced Fiber Materials Springer Journals

Versatile Recyclable Kevlar Nanofibrous Aerogels Enabled by Destabilizing Dynamic Balance Strategy

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Publisher
Springer Journals
Copyright
Copyright © Donghua University, Shanghai, China 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
ISSN
2524-7921
eISSN
2524-793X
DOI
10.1007/s42765-023-00273-9
Publisher site
See Article on Publisher Site

Abstract

Aerogels are of great interest in diverse fields including thermal insulation, environmental protection, liquid separation, electromagnetic shielding, etc. However, the development of renewable and recyclable aerogels, especially synthetic polymer-based ones, remains an enormous challenge, which seriously hinders the practical application of aerogels. Herein, utilizing Kevlar nanofibers (KNFs) as representative synthetic polymer building blocks, a destabilizing dynamic balance (DDB) strategy is proposed to fabricate recyclable aerogels with high reprocessing consistency. More specifically, aprotic esters (e.g., di-tert-butyl decarbonate, DiBoc) and alkalis (e.g., potassium tert-butoxide, t-BuOK) are introduced to trigger the destabilizing dynamic balance between deprotonation–protonation of KNFs, resulting in a reversible sol–gel transition. Meanwhile, the duration of sol–gel transition (i.e., gelation) time, adjustable from 10–2 to 103 min, is compatible with versatile processing methods, such as static mould casting, dynamic wet spinning, dynamic blade coating and dynamic 3D printing. These unique advantages enable the fabrication of various KNF aerogel products (i.e., continuous fibers, continuous films, large-sized monoliths and 3D-printed articles) with low density (33–165 mg/cm3), high compressive modulus (up to 52 MPa), high specific surface area (360–404 m2/g) and low thermal conductivity (0.027–0.050 W/m·K). Notably, these properties are comparable or superior to that of previously reported KNF aerogels and far superior to that of recyclable aerogels. Compared with direct fabrication from raw materials, the DDB strategy reduces the cost by 50.5% and 82.5% when products are made from recycled aerogels and wet gels, respectively. Such cost reduction further increases with the number of recycling cycles, which is calculated as $275 per kilogram KNF aerogel with 5 cycles. This work develops extraordinary KNF aerogels those can be recycled and reused, as well as provides a strategy that can be applied to design more recyclable aerogels.Graphical Abstract[graphic not available: see fulltext]

Journal

Advanced Fiber MaterialsSpringer Journals

Published: Jun 1, 2023

Keywords: Aerogel; Kevlar; Recyclability; Versatile processing; Dynamic balance

References