Dynamic Cross-Linking Chemistry Enables Advanced One-Component Thermosets

Abstract

This work discloses a new strategy based on dynamic cross-linking chemistry to achieve advanced one-component thermosets combining ultralong storage life and fast cross-linking. One-component thermosets containing resin and cross-linker in one pot have the features of simple operation, stable quality, and low waste; however, an urgently needed one with long storage life at room temperature and fast cross-linking at medium–low temperatures (≤130 °C) remains an enormous challenge. Herein, we innovatively propose a strategy of dynamic cross-linking and controlled dissolution to address this issue. As an example, a dynamic cross-linked cross-linker (DCC) is synthesized via Diels–Alder reaction to hide the high activity of a commercial amine-type cross-linker. A one-component thermoset from a DCC and a commercial diepoxy monomer can be stored for an ultralong time at room temperature and cross-linked rapidly below 130 °C. Moreover, the DCC can also serve as a latent accelerator for epoxy/anhydride thermosets with the same storage life as the control system with no accelerator at room temperature and fast cross-linking at elevated temperatures. This work is beneficial for promoting the application of dynamic cross-linking chemistry and meeting the urgent need for advanced one-component thermosets in the fields of advanced composites, coatings, electronic packaging materials, automotive and electronic adhesives, etc.