Abstract:

Reconciling mechanical robustness with sustainability remains a paramount challenge in polymer science, for which Covalent Adaptable Networks (CANs) have emerged as a solution. To fully realize the circular polymer engineering, this field is pivoting toward bio-derived building blocks. Natural thioctic acid (TA) represents an ideal candidate due to its dual-reactive structure. However, the thermodynamic instability of TA homopolymers hinders the practical application. Herein, we present a versatile “bottom-up” molecular strategy to overcome this bottleneck. A series of TA-derived CANs (TCANs) featuring dual-crosslinked networks was prepared through the crosslinking of TA with a library of epoxy monomers, demonstrating the methodological robustness. In this design, nascent poly(disulfide) chains are anchored within a robust ester?linked scaffold, which kinetically suppresses their depolymerization and improves strength. The TCANs exhibit tunable mechanical properties, with tensile strength of 2.23–47.06 MPa and Young's modulus of 24.56–1276.42 MPa, systematically correlating with the epoxy structure. Notably, TCANs integrate a suite of functional properties, including self-healing, thermal processability, and chemical degradation. The TCANs also demonstrate high-efficiency adhesive performance with a maximum lap-shear strength of 3.43 MPa. This work addresses the inherent instability of TA-based polymers, and provides a molecular blueprint for the next generation of sustainable materials.