Mechanically robust inorganic/organic hybrid polyurethane films with excellent self-healing and anti-corrosion ability

Self-healing efficiency and mechanical strength have always been a mechanical contradiction for polymers. In this work, the isocyanate terminated polyurethane and amidoxime modified silica nanoparticles were crosslinked by oxime-urethane bonds to prepared a self-healing polyurethane nanocomposite with mechanical enhancement. The optimal nanocomposite (OUs@5SiNPs) exhibited remarkable mechanical properties with a tensile strength of 33.64 MPa and toughness of 131.48 MJ m- 3. In addition, the nanocomposite had excellent self-healing properties with a self-healing efficiency of 95.6%. Moreover, the nanocomposite coating exhibited corrosion protection against mild steel due to the barrier effect of the incorporated nanoparticles and the formed crosslinked structure. The impedance modulus of OUs@5SiNPs at 0.01 Hz was 1.6 x 108 omega cm2. The nanocomposite can conveniently heal and regain the original mechanical properties and corrosion performance triggered by thermo. This combination of strength and self-healing ability of the composite can prolong the durability of the material in harsh environments and is of great value for the development of corrosion resistant coatings for metals.