Enabling the Reprocessability and Debonding of Epoxy Thermosets Using Dynamic Poly(β‐Amino Amide) Curing Agents

Abstract

Epoxy resins, by showing outstanding performances, stand out as the most applied materials in thermoset products. However, their excellent properties, associated with covalently cross‐linked structures, come at the expense of recyclability, thus posing environmental and regulatory challenges. Herein, starting from the recently explored reversibility of robust poly(β‐amino amide)s, dynamic curing agents are synthesized in a one‐pot procedure for their use in the preparation of epoxy‐derived dynamic networks. The obtained materials retain desirable properties while being fully (re)processable, with high temperature‐dependent viscoelasticity (activation energy (Ea) of ≈230 to 270 kJ mol−1). Moreover, this new generation of epoxy materials shows excellent resistance to hydrolysis and creep at elevated temperatures (up to 120 °C). As an entry point to further applications, the reversible curing agents are implemented in adhesive formulations, showcasing lap shear strengths that are comparable to commercial hardeners (up to 9 MPa). The β‐amino amide groups provide the obtained adhesives with the additional functionality of heat‐triggered deconstruction at elevated temperatures (130 to 150 °C), and re‐bonding capacity with up to 80% recovery in lap‐shear strength. To encourage industrial adoption, a cost‐effective, drop‐in synthesis protocol is developed using only bulk chemicals, hence facilitating practical implementation.