Rigid Biobased Vinylogous Urethane Vitrimers from d‑isosorbide/Furfural-Derived Monomers

Biobased covalent adaptable networks (CANs, vitrimers) that combine high glass transition temperatures, mechanical robustness, and reprocessability remain scarce, particularly in vinylogous urethane vitrimer chemistry. Herein, we report the synthesis of rigid vinylogous urethane CANs derived from biobased d-isosorbide bis-acetoacetate and the furfural-based diamine propane-2,2-di-(2-furylmethylamine) (PDFA). The materials were prepared by a solvent-free bulk curing strategy using mixtures of di- and trifunctional amines, enabling direct formation of cross-linked networks without additional processing solvents. The use of PDFA significantly increased the renewable carbon content while maintaining the rigidity required for glassy high-performance materials. The resulting networks exhibited tunable thermomechanical properties depending on amine structure and composition, with glass transition temperatures up to 125 °C and thermal stability up to 290 °C. Stress-relaxation experiments confirmed fast catalyst-free bond exchange in the rubbery state, with relaxation occurring on the scale of tens to hundreds of seconds and activation energies dependent on the diamine structure. Selected materials displayed efficient reprocessability by compression molding while largely preserving their thermal and tensile properties after recycling. These results demonstrate that combining d-isosorbide with a rigid furfural-derived diamine is an effective strategy toward biobased, glassy vinylogous urethane vitrimers that unite high renewable carbon content, elevated service temperature, and recyclability.