Mechanical‐Bond‐Toughened Epoxy Resins

Abstract Epoxy resins, while indispensable for their excellent mechanical strength, face fundamental limitations due to their inherent brittleness. Here we present a novel advancement in epoxy toughening through the strategic incorporation of [2]rotaxane‐based mechanical bond as mechanically interlocked cross‐linker, whose unique intramolecular motion enables efficient energy dissipation and stress redistribution under external force. As a result, the as‐prepared mechanically interlocked epoxy networks ( MIN EP) exhibit elongation of 272% and toughness of 37.9 MJ m −3 , both representing an order‐of‐magnitude improvement over the conventional counterpart while showcasing notable properties compared to other epoxy materials. Further, we capitalize on the adhesive effect and good toughness of MIN EP to toughen graphene films. Compared to pristine graphene films, the MIN EP‐bonded films show significantly enhanced toughness (30.2 versus 3.4 MJ m −3 ), elongation (26.5% versus 9.9%), and maximum strength (237 versus 72.3 MPa). This work not only provides an effective strategy for the development of high‐performance epoxy resins, but also exploits their application potential in toughening two‐dimensional (2D) materials.