Supramolecular Polymer Additives as Repairable Reinforcements for Dynamic Covalent Networks.

Employing rigid (in)organic materials as reinforcement for dynamic covalent networks (DCNs) is an effective approach to develop high-performance materials. Yet, recycling of these materials after failure often necessitates inefficient chemical reprocessing or inevitably alters their performance due to unrepairable inert components. Here, a non-covalent reinforcement strategy is presented by introducing a supramolecular additive to a DCN that can reversibly depolymerize and reform on demand, therefore acting as an adaptive and repairable reinforcement. The strong hydrogen-bonding interactions in the supramolecular polymer of triazine-1,3,5-tribenzenecarboxamide (S-T) strengthen the DCN at room temperature, while its non-covalent nature allows for easy one-pot reprocessing at high temperatures. Depending on wether S-T is covalently bond to the DCN or not, it can play either the role of compatibilizer or filler, providing a synthetic tool to control the relaxation dynamics, reprocessability and mechanical properties. Moreover, the S-T reinforcement can be chemically recovered with high yield and purity, showcasing the recyclability of the composite. This conceptually novel supramolecular reinforcement strategy with temperature-controlled dynamics highlights the potential of supramolecular polymer additives to replace conventional unrepairable reinforcements.