Combination of Dynamic and Permanent Cross-Linking: A Pathway to Enhance Elasticity and Recyclability

Thermosetting materials exhibit advantages such as dimensional stability and elasticity but lack reprocessability due to their permanently cross-linked internal structure. Introducing a reversible cross-linked network endows materials with reprocessability but often compromises resilience and mechanical properties. Hence, it is still a significant challenge to develop recyclable elastomers with high elasticity as traditional thermosetting materials and remolding ability as traditional thermoplastic materials. Based on this, this work incorporates both reversible and irreversible cross-linked networks into a polyurethane system, constructing synergistic networks with distinct properties to achieve high elasticity and reprocessability simultaneously. In addition, by adjusting the proportion of the synergistic networks, the relationship between elasticity and reprocessability in different materials was investigated, revealing the synergistic effect between the dynamic network and the chemical cross-linked network. This work provides theoretical support for the design of elastomer materials that combine the high resilience of thermoset materials with the remolding ability of thermoplastic materials.