Abstract:The aromatic compound ethylenediamine Schiff base (ESS) with double imine bond structure was synthesized using ethylenediamine and salicylaldehyde as raw materials, and the structure was characterized by IR spectroscopy and NMR, which proved the successful synthesis of the compound. Then, a polyurethane sample (EPU) was prepared using ESS as chain extender. The structural composition was analyzed by infrared spectroscopy. The thermal stabilities and damping properties of the polyurethane were investigated by heat loss analysis and dynamic thermo-mechanical analysis. The self-repairing properties were characterized by mechanical property test and optical microscopic observation. The effects of imine bonding and different additive ratios on the properties of the polyurethane were analyzed. The results indicate that the effective damping temperature range of the EPU samples can be extended from ﹣5 ℃ to 100 ℃. Following the principle of time-temperature equivalence, the effective frequency range can be extrapolated to 0.1~103 Hz, demonstrating excellent damping performance. With the tensile strengths of 11.97~16.89 MPa and elongation at break of 726%~498%, the EPU samples show excellent mechanical properties. Meanwhile, the EPU material demonstrate excellent self-repairing capabilities under mild stimulation conditions. Specifically, 87.9% of its mechanical properties are recovered after being repaired at 40 ℃ for 12 h. Additionally, surface scratches are effectively healed after being repaired at 60 ℃ for 5 min. Notably, the repairing ability of the EPU material is found to be superior under acidic conditions.