Abstract:The metal-ligand coordination, as a crosslinking agent, has attracted much attention in supramolecular chemistry because of its dynamic properties and different association strengths. In order to make polyurethane film have better mechanical strength and self-healing efficiency, in this study, the polyurethane (PU-DAP) was synthesized by using 2, 6-diaminopyridine (DAP) as chain extender, and then different amounts of anhydrous ferric chloride were used as crosslinking agent to coordinate with PU-DAP. A series of self-healing polyurethane films (PU-DAP/ Fe3+) were synthesized. The single factor experiment results showed that when n(DAP): n(Fe3+) was 2:1, the mechanical properties and self-healing properties of PU-DAP/Fe3+2:1 film were the best. The FTIR results showed that Fe3+ was successfully coordinated with nitrogen and oxygen on pyridine and amide groups. The thermogravimetric analysis results showed that the thermal decomposition temperature of PU-DAP/Fe3+2:1 film was increased by 17.15 ℃, which indicated that the thermal stability was enhanced by the crosslinking structure formed via the introduction of Fe3+. The self-healing experiment and polarizing microscope testing results showed that the tensile strength and self-healing efficiency of the film were 5.16 MPa and 93.2%, respectively. And the scratches completely disappeared after 36 h at room temperature. Compared with PU-DAP, its mechanical strength and self-healing efficiency were both improved.
