Design of Reversible Adhesives by Using a Triple Function of Ionic Liquids
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In: Macromolecular materials and engineering, Vol. 309.2024, No. 9, 2400011, 02.05.2024.
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TY - JOUR
T1 - Design of Reversible Adhesives by Using a Triple Function of Ionic Liquids
AU - Wanghofer, Florian
AU - Kriehuber, Matthias
AU - Reisinger, David
AU - Floh, Florian
AU - Wolfahrt, Markus
AU - Schlögl, Sandra
N1 - Publisher Copyright: © 2024 The Authors. Macromolecular Materials and Engineering published by Wiley-VCH GmbH.
PY - 2024/5/2
Y1 - 2024/5/2
N2 - Reversible adhesives are crucial for a circular economy of composites as they play a key role for rework, repair, and recycling of adhesively bonded components. Herein, electrically debondable adhesives are prepared by introducing ionic liquids in dynamic thiol–epoxy networks. The function of the ionic liquid in the networks is threefold as it accelerates the curing reaction between thiol and epoxy monomers, facilitates electrical debonding, and catalyzes thermoactivated transesterification reactions, required for rebonding at elevated temperature. A library of 1,3-dibutylimidazolium-based ionic liquids with varying anions is synthetized and it is found that 1,3-dibutyl-1H-imidazol-3-ium dicyanamide (DiButIm─N(CN)2) is superior in accelerating bond-exchange reactions between hydroxy and ester moieties at elevated temperature. Thus, a thiol–epoxy resin containing 20 wt% of DiButIm─N(CN)2 is used to impregnate glass fiber mats yielding adhesive connections for aluminum substrates with 10.2 MPa pull-off strength. The adhesive connections are successfully debonded at the metal–adhesive interface by applying 120 V. The samples are then rebonded via the thermoactivated change in the networks’ viscoelastic properties and ≈80% (8.1 MPa) of their original bond strength can be regained. By providing a simple strategy to synthetize reversible adhesives, this approach paves a way toward improved recyclability and repairability of adhesively bonded structures.
AB - Reversible adhesives are crucial for a circular economy of composites as they play a key role for rework, repair, and recycling of adhesively bonded components. Herein, electrically debondable adhesives are prepared by introducing ionic liquids in dynamic thiol–epoxy networks. The function of the ionic liquid in the networks is threefold as it accelerates the curing reaction between thiol and epoxy monomers, facilitates electrical debonding, and catalyzes thermoactivated transesterification reactions, required for rebonding at elevated temperature. A library of 1,3-dibutylimidazolium-based ionic liquids with varying anions is synthetized and it is found that 1,3-dibutyl-1H-imidazol-3-ium dicyanamide (DiButIm─N(CN)2) is superior in accelerating bond-exchange reactions between hydroxy and ester moieties at elevated temperature. Thus, a thiol–epoxy resin containing 20 wt% of DiButIm─N(CN)2 is used to impregnate glass fiber mats yielding adhesive connections for aluminum substrates with 10.2 MPa pull-off strength. The adhesive connections are successfully debonded at the metal–adhesive interface by applying 120 V. The samples are then rebonded via the thermoactivated change in the networks’ viscoelastic properties and ≈80% (8.1 MPa) of their original bond strength can be regained. By providing a simple strategy to synthetize reversible adhesives, this approach paves a way toward improved recyclability and repairability of adhesively bonded structures.
KW - dynamic polymer networks
KW - electrical debonding
KW - ionic liquids
KW - reversible adhesives
KW - vitrimers
UR - http://www.scopus.com/inward/record.url?scp=85191783321&partnerID=8YFLogxK
UR - https://pureadmin.unileoben.ac.at/portal/en/publications/design-of-reversible-adhesives-by-using-a-triple-function-of-ionic-liquids(a83ca346-617b-4d65-8ad0-bffb63220f62).html
U2 - 10.1002/mame.202400011
DO - 10.1002/mame.202400011
M3 - Article
AN - SCOPUS:85191783321
VL - 309.2024
JO - Macromolecular materials and engineering
JF - Macromolecular materials and engineering
SN - 1438-7492
IS - 9
M1 - 2400011
ER -