Microbranching-Stabilized Dynamic Epoxy Networks for Rapid-Curing, Mechanically Robust, and Upcyclable Thermosets

Rapid-curing epoxy thermosets are highly attractive for scalable composite manufacturing, yet rapid network formation often compromises cure homogeneity, mechanical robustness, and end-of-life reuse. Here, we report a microbranching-stabilized dynamic epoxy network that integrates rapid curing, balanced strength and toughness, and thermoset upcycling. A liquid mixed amine curing agent (Gm-12) featuring a precisely designed microbranching architecture forms a homogeneous liquid-liquid blend with a commercial epoxy monomer, allowing complete curing within 10 min at 150° C. The resulting epoxy network (DGm-12) develops a well-defined microphase-separated morphology that preserves a high effective crosslink density while introducing dissipative domains, thereby achieving a tensile strength of 88 MPa and a fracture toughness of 3.5 MPa m^1/2. The incorporation of dynamic ester and disulfide bonds further enables rapid network rearrangement and full reprocessability. Consequently, partially cured or expired prepregs can be reused, fully cured composites can be reshaped, and clean carbon fibers can be recovered through hydrothermal degradation in water. Together, these results establish a design principle for reconciling rapid curing, strong and tough mechanical performance, and composite-level upcycling in epoxy thermosets.