Exploring transamidation and chemical recycling of β-amino amide-derived covalent adaptable networks

Abstract

The growing environmental challenge of non-recyclable thermosets underscores the urgent need for sustainable alternatives. Covalent adaptable networks (CANs) containing dynamic β-amino amide moieties have emerged as promising reprocessable polymer networks, combining mechanical robustness with recyclability. In this work, we elucidate the exchange kinetics of both the well-established (retro)-aza-Michael addition and a newly identified transamidation pathway that is operative in β-amino amides. Systematic catalyst screening reveals that acidic catalysts significantly enhance viscoelastic control, thereby improving (re)processing efficiency. Furthermore, we introduce a chemical recycling protocol that enables the recovery of the original amino building blocks with up to 86% purity, demonstrating their direct use as feedstock in material (re)synthesis. These insights advance the fundamental understanding of dynamic bond exchange in β-amino amide based CANs and establish a viable route towards circular thermoset materials for numerous applications.