Dangling-Chain Topology Enables Synergistic Dissipation in Hierarchical Aggregate Elastomers

Abstract Polyurethane elastomers are favored for damping applications owing to their tunable structure and effective vibration attenuation. However, conventional systems, which rely primarily on segmental mobility within the glass transition region, often struggle to achieve high damping performance over a broad frequency range. To overcome this limitation, we developed a novel polyurethane elastomer by incorporating dangling chains functionalized with dynamic bonds of varied strengths. The superposition of these interactions drives the formation of hierarchical aggregated structures within the polymer network. The resulting material, denoted PU-I30-CC, utilizes zwitterionic aggregates and coordination bonds to broaden and enhance its relaxation spectrum, enabling stable energy dissipation even under high-frequency excitation. Consequently, it exhibits an outstanding combination of mechanical and damping properties: a tensile strength of 44.9 MPa, an elongation at break of 1292%, a toughness of 272.6 MJ/m3, and excellent high-frequency damping performance, as validated by rheological and impact tests. This work provides a new design strategy to break the conventional trade-off between mechanical robustness and damping capacity in polyurethane elastomers.