Dynamic cross-linked topological network reconciles the longstanding contradictory properties of polymers

There is usually a trade-off between high-tensile properties and processability in polymers because the mechanisms of these properties are mutually exclusive. Here, we design a chemically coupled four-arm dynamic polymer cross-link site to overcome this challenge. By concurrently increasing cross-link sites and dynamic bond contents, this approach fabricates polymer networks with high cross-link density yet low processing temperature, challenging the conventional structure-property relationship where cross-linking inherently limits plasticity. Notably, the material demonstrates remarkable processability, evidenced by the ratio of G'_max to G'_min with a temperature differential (ΔT) of 120°C (which signifies the soft-to-hard transition capability). This ratio reaches 153.3, higher than all reported cross-linked polyurethanes. This work represents a molecular strategy that combines electronic effect and topology network design to modulate materials' properties, and it will be useful for developing next-generation materials.