Ultra‐Tough Poly(Urea‐Urethane) Plastics With Superior Impact Resistance for Cryogenic Applications

Abstract Traditional impact‐resistant plastics become brittle at low temperatures due to restricted polymer chain mobility, rendering them unsuitable for cryogenic applications. Developing ultra‐tough plastics with superior impact resistance under extreme low‐temperature conditions remains a significant challenge. Here, this study reports the fabrication of ultra‐tough, impact‐resistant poly(urea‐urethane) (PUU) plastics by cross‐linking soft poly(tetramethylene ether glycol) (PTMEG) chains through multiple types of hydrogen bonds and hydrogen‐bond aggregates with varying binding energies. The PUU plastic features a bicontinuous phase‐separated nanostructure, where hydrogen‐bond‐cross‐linked, rigid yet deformable domains are interpenetrated with soft PTMEG chains. At −50 °C, the plastic exhibits mechanical properties comparable to those of ultra‐tough, high‐strength plastics at ambient temperature, with yield strength of 81.1 MPa, breaking strength of 133.0 MPa, Young's modulus of 1.5 GPa, and breaking strain of 220.9%. A 0.3‐mm‐thick sample achieves a maximum impact force of 667.8 N and an impact energy of 3.8 J at −50 °C, while maintaining exceptional mechanical robustness and flexibility even at −196 °C. The low‐temperature toughness and impact resistance of the PUU plastics surpass those of existing impact‐resistant plastics. This study demonstrates that hydrogen bonds with a broad spectrum of binding energies serve as ideal cross‐links for fabricating ultra‐tough, impact‐resistant plastics suitable for cryogenic applications.