Self-healing polyurethane composite films loaded with Ni@C nanoparticles

Widely employed as polymers, polyurethanes also struggle to strike a balance between mechanical and self-healing qualities. Extrinsic self-healing can readily result in the production of material defects and stress concentration, which can result in the loss of mechanical property. In this study, self-healing and mechanical properties were combined to create a self-healing polyurethane nanocomposite film (PUHN) with good fatigue resistance. Reversible hydrogen and disulfide bonds were introduced to the polyurethane film, meanwhile, carbon-coated nickel nanoparticles were dispersed into the matrix as fillers during the early stage of polymerization. The results showed that PUHN combines outstanding mechanical properties with excellent self-healing properties, while the tensile strength of PUHN was increased by 38 % to 2.32 MPa due to the small-size effect caused by the introduction of nanoparticles. The introduction of reversible disulfide bonding and the presence of abundant hydrogen bonding give PUHN excellent self-healing properties, which can reach 91.2 % self-healing efficiency after 3 h in an oven at 80℃. Meanwhile, the fatigue resistance of the composite material also shows considerable application potential for use in packaging.