Epoxy‐Thiol Click Chemistry as a Platform for In Situ Preparation of New Reversible Thermoplastic Adhesives

Thermally reversible adhesive systems combining high thermomechanical performance with recyclability remain a major challenge in polymer science. This study presents heat‐reversible polymers prepared via a two‐component (2K) liquid system through in situ step‐growth polymerization between difunctional thiols and difunctional epoxy resins. The influence of thiol structure (aliphatic, cycloaliphatic, and aromatic) on polymer formation, thermal behavior, and adhesion was investigated. The use of selected difunctional thiols enabled the formation of materials with suitable adhesive properties, highlighting the key role of thiol chemistry in determining final performance. The best systems exhibited glass transition temperatures ( T g ) of 45°C–60°C by dynamic mechanical analysis and softening temperatures above 130°C. Adhesion performance, evaluated by lap shear strength measurements on aluminum substrates, showed that good adhesion is maintained at 80°C. Above the softening temperature, adhesion decreases significantly, allowing reversible debonding. Repeated debonding and rebonding cycles demonstrate that optimized systems can be reprocessed within minutes at moderate temperatures with minimal loss of mechanical properties. Overall, this work introduces an epoxy‐thiol adhesive platform with controlled thermal debonding and true reversibility, while preserving performance, enabling sustainable and reworkable bonding systems.