Synergistic Enhanced Stiffness in Reversible Interlocked Polymer Networks by Orthogonal Triple Dynamic Bonds

The achievement of balance between mechanical stiffness and dynamic adaptability remains a formidable challenge in the development of covalent adaptable networks (CANs). Herein, we report a reversible interlocked network (RILNS) system constructed from three orthogonal dynamic bonds, i.e., boronic esters, imines, and disulfides, that exhibits a remarkable enhancement in stiffness performance. This RILNS is fabricated through the topological interlocking of a boronic ester-based epoxy soybean oil network (SN-BDB) and an imine/disulfide-containing polyurethane network (SN-CN-SS). The interlocked architecture provides a permanent reinforcing scaffold where the synergistic orthogonal exchange of the triple dynamic bonds actively drives network reorganization into a more uniform and densely cross-linked structure. As a result, the RILNS delivers a Young’s modulus of 94 MPa, which represents a marked enhancement over the values of 22 MPa for SN-BDB and 32 MPa for SN-CN-SS. Notably, the dynamic performance characteristics are well retained, as corroborated by a high self-healing efficiency of 94% and outstanding reprocessability under moderate thermal conditions. Stress relaxation analysis further confirms a lower activation energy for the interlocked network, suggesting the augmented dynamics stemming from the synergistic interplay of triple dynamic bonds. This work establishes an interesting strategy for designing self-reinforcing and self-adaptive sustainable polymers.