Synergistic Effects of Mechanical Topology and Chemical Exchange in Dynamic Covalent Networks Incorporated with Polyrotaxane

초록

While dynamic covalent networks (DCNs) have garnered increasing attention as reprocessable thermosets, their mechanical and dynamic behaviors need further optimization. Most existing approaches rely on chemically tuning bond exchange reactions; however, the topological design of the network, particularly through the integration of mechanically interlocked bonds (MIBs), has not been systematically explored. In this study, we investigate the impact of polyrotaxane (PR)-based MIBs on the reconfigurability and mechanical performance of vinylogous urethane-based DCNs by designing networks with non-sliding (fixed) and sliding (PR-containing) polymers. The PR-based systems are further categorized according to their direct or indirect participation in amine exchange reactions. Incorporating PRs into DCNs significantly enhanced relaxation dynamics, reprocessability, and toughness. Among them, the DPRam network, featuring aminated PR capable of directly participating in the bond exchange, shows the lowest activation energy (85.3 kJ mol-1), the highest toughness retention (94.8%), the best reprocessing ability, and the fastest shape recovery. These advantages are attributed to the synergistic combination of slidable topology and dynamic covalent reactivity. This study highlights the potential of integrating PRs into a structural design strategy to advance topologically adaptive, high-performance DCN systems.

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