A Robust Self-healing Polyurethane Elastomer Enabled by Tuning the Molecular Mobility and Phase Morphology through Disulfide Bonds

Abstract

Elastomers with outstanding strength, toughness and healing efficiency are highly promising for many emerging fields. However, it is still a challenge to integrate all these beneficial features in one elastomer. Herein, an asymmetric alicyclic structure adjacent to aromatic disulfide was tactfully introduced into the backbone of polyurethane (PU) elastomer. Specifically, such elastomer (PU-HPS) was fabricated by polycondensing polytetramethylene ether glycol (PTMEG), isophorone diisocyanate (IPDI) and p-hydroxydiphenyl disulfide (HPS) via one-pot method. The molecular mobility and phase morphology of PU-HPS can be tuned by adjusting the HPS content. Consequently, the dynamic exchange of hydrogen and disulfide bonds in the hard segment domains can also be tailored. The optimized sample manifests outstanding tensile strength (46.4 MPa), high toughness (109.1 MJ/m3), high self-healing efficiency after fracture (90.3%), complete scratch recovery (100%) and good puncture resistance. Therefore, this work provides a facile strategy for developing robust self-healing polymers.