An Ultrastrong, Impact-Resistant Shape Memory Polyurethane Enabled by Synergistic Steric Hindrance and Dual Noncovalent Interactions

Developing elastomer materials that integrate mechanical properties with impact resistance remains a key challenge for fields such as surface protection, impact mitigation, and damping applications. Inspired by the β-sheet nanostructure of spider silk, this study proposes a strategy based on the synergistic design of steric hindrance and dual noncovalent interactions (hydrogen bonds (H-bonds) and π–π stacking). The prepared IPUU-D 0.5 elastomer demonstrates a tensile strength of 90.4 MPa, recovery after 2000 stretching cycles, and shape memory properties. The steric hindrance effect inhibits the excessive aggregation of hard segments, while the multiple H-bonds and π–π stacking interactions synergistically strengthen the directional arrangement and structural support within the molecular network. Remarkably, under ultrahigh strain-rate impact (9000 s –1 ), the IPUU-D 0.5 elastomer shows impact strength reaching 1830.0 MPa and toughness of 427.9 MJ m –3 . The synthesis strategy represents a viable route for the design of next-generation, high-performance protective materials.