Strain-Hardening, impact protective and Self-Healing supramolecular polyurethane nanocomposites enabled by quadruple H-Bonding, disulfide bonds and nanoparticles.

• Synthesized supramolecular elastomer contains disulfide bonds and quadruple H-bonds. • The elastomer has strain-hardening, self-standing, and self-healing properties. • Silica nanoparticles further enhanced energy absorption and hindered relaxation. • Sacrificial bonds and nanoparticles contributed to the high energy absorption. Developing protective materials with intelligent and stimuli-responsive properties is indispensable for safety protection. However, combining contradictory characteristics into a single polymer is challenging, such as high mechanical strength, impact protection, and self-healing properties. Herein, a strain-hardening supramolecular polyurethane nanocomposite (SPN) with high mechanical strength and unique impact protection characteristics is synthesized by incorporating quadruple hydrogen bonds (H-bonds), disulfide bonds, and modified silica nanoparticles into polyurethane elastomer. Benefiting from the dynamic break and re-form characteristic of quadruple H-bonds and the stress dissipation behavior of nanoparticles, SPN exhibits high energy absorption efficiency and impact protection properties. During the drop ball striking test, the impact energy absorption efficiencies reached 90%, and the buffer time of impact was significantly longer than common buffering materials. The SPN exhibited excellent stretchability and self-healing ability, ascribing to disulfide metathesis and H-bonds association. Moreover, the prepared SPN could be easily processed through a hot press and showed negligible creeping. The developed SPN could serve as a novel self-standing impact protective material that offers promising prospects in sports, transportation, and aerospace fields. [ABSTRACT FROM AUTHOR]