Dissociate transfer exchange of tandem dynamic bonds endows covalent adaptable networks with fast reprocessability and high performance

Abstract

Development of covalent adaptable networks (CANs) has connected thermosets and thermoplastics and brought about various functions. However, combining the high performance of thermosets and fast reprocessability of thermoplastics is still a challenge for CANs. Herein, we proposed a strategy of dissociate transfer exchange (DTE) of tandem dynamic bonds to achieve continuous reprocessability for CANs without compromising thermal and mechanical properties. Epoxy monomers with tandem imine and disulfide bonds were synthesized and cross-linked to produce CANs. The dissociation of disulfide bonds significantly increased the mobility of imine bonds in series with the breaking points, leading to a fast exchange rate and reprocessability and the high cross-link density and rigidity of the network provided good thermal and mechanical properties. We anticipate that this strategy can efficiently accelerate various functions such as shape-shifting and self-healing as well as reprocessing and welding and should be universally applied to other tandem dynamic systems.