3D Printing of Strong, Tough, Multifunctional and Sustainable Material from Dynamic Imidazole-urea-epoxy Chemistry

Photo-curing three-dimensional (3D) printing enables complex geometries, personalized customization, rapid curing, and excellent spatial resolution; however, conventional photocured resins often suffer from limited mechanical performance, functionality, and sustainability. Herein, we present a novel photothermal dual-curing strategy based on dynamic imidazole-urea-epoxy chemistry to produce 3D printed materials with exceptional strength and toughness. This chemistry is triggered during post-printing thermal treatment, which not only creates new covalent crosslinks, but also synergistically integrates the toughness of polyurethane with the strength of epoxy, resulting in a reinforced network. This transformation also drives a dramatic 26-fold increase in the elastic modulus (from 13 MPa to 338 MPa), enabling a single material to be programmed from a soft and flexible state into a rigid and structural solid. Such a stark property shift unlocks unique functionalities, including shape programmability, enhanced portability, and adaptive performance for multiscenario applications. Furthermore, we extend this strategy to commodity polyurethane foam (PUF) waste and successfully upcycle it into high-performance 3D printing resins. Our work establishes a versatile approach for manufacturing strong, tough, multifunctional, and sustainable 3D printed materials.