Mechanical Response of <scp>PBDMS</scp> ‐Modified <scp>SEBS</scp> Shear Thickening Gels: A Study of High and Low Strain‐Rate Behavior

ABSTRACT The dynamic mechanical behavior of Polyborosiloxane (PBDMS)/Styrene‐Ethylene‐Butylene‐Styrene (SEBS) composites was systematically investigated to elucidate the strain‐rate‐dependent reinforcement mechanism governed by reversible BO coordination bonds. The composites were prepared via physical blending, integrating the dynamic supramolecular network of PBDMS with the physically crosslinked SEBS matrix. Rheological and infrared analyses confirmed the successful formation of dual‐network structures composed of SEBS physical crosslinks and PBDMS dynamic coordination domains. At low strain rates, the introduction of PBDMS slightly decreased the quasi‐static strength but significantly improved strain‐rate sensitivity. Cyclic compression and hysteresis tests demonstrated superior energy dissipation and structural recoverability, as the dynamic BO bonds reversibly reorganized under stress, resulting in only ~5% residual strain after ten cycles. High strain‐rate experiments conducted using a modified Split Hopkinson Pressure Bar (SHPB) revealed four distinct deformation stages—elastic deformation, yielding, stress softening, and strain hardening—accompanied by substantial strain‐rate strengthening. The exceptional impact resilience originates from the synergistic coupling between the dynamic BO bond network and SEBS physical crosslinks, which collectively enable rapid energy dissipation and adaptive network recovery. This work provides a new strategy for designing dynamic supramolecular elastomers with tunable strain‐rate sensitivity and high‐efficiency impact protection.