Design of Reversible Adhesives by Using a Triple Function of Ionic Liquids

Florian Wanghofer, Matthias Kriehuber, David Reisinger, Florian Floh, Markus Wolfahrt, Sandra Schlögl

Research output: Contribution to journalArticleResearchpeer-review

Abstract

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.
Original languageEnglish
Article number2400011
Number of pages9
JournalMacromolecular materials and engineering
Volume??? Stand: 10. Juli 2024
Issue number??? Stand: 10. Juli 2024
Early online date2 May 2024
DOIs
Publication statusPublished - 2 May 2024

Bibliographical note

Publisher Copyright: © 2024 The Authors. Macromolecular Materials and Engineering published by Wiley-VCH GmbH.

Keywords

  • dynamic polymer networks
  • electrical debonding
  • ionic liquids
  • reversible adhesives
  • vitrimers

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