Kinetically and Thermodynamically Controlled Cross-Linking in Sustainable Digital Light Processing Printing: Enabling Thermoset Reprocessing via Thermal Leveling Effect

High-performance resins are essential for digital light processing (DLP) 3D printing, yet most are thermosetting and lack reprocessability. Recently developed covalent adaptive networks address this limitation, but their reliance on specialized monomers hinders scalability and practical application. Herein, we report a 3D-printable resin formulated with isobornyl acrylate, a 1,2-diol-based boronic ester cross-linker (<4%), and tetradecanol as a trans-borylesterification mediator. At room temperature, tetradecanol remains unreactive, preserving a rigid thermoset matrix while forming microelastic domains that dissipate impact energy, achieving an 8600% increase in toughness with 15% tetradecanol. During hot pressing, the thermal leveling effect kinetically drives dynamic bond exchange, converting the thermoset into a thermoplastic material. Upon cooling, the reaction becomes thermodynamically controlled again, reestablishing the thermoset polymer network and recovering its mechanical properties. This resin uniquely transitions to a thermoplastic state only during reprocessing, reverting to a durable thermoset upon cooling, enabling sustainable, high-performance DLP printing with end-of-life reusability.