It's necessary to develop self-healing polymers, which will significantly improve the safety and service life of artificial materials. Although extensive research efforts have been devoted to the field, it is still a challenge to synthesize hard and tough polymers, which own self-healing ability under mild conditions. In this work, we fabricated a hard and tough thermoplastic polyurethane (TPU, PCL-HM) and the wound of PCL-HM can be quickly healed under mild conditions (50 °C). Comprehensive characterization results suggest that the Young's modulus, tensile strength and elongation at break of PCL-HM can reach 76 MPa, 11.8 MPa and 841%, respectively, which is better than most recently reported TPUs. PCL-HM prepared with aromatic disulfide bonds as dynamic covalent bonds, polycaprolactone diol (PCL-2000) as soft segment, isophorone diisocyanate (IPDI) and dicyclohexylmethane-4,4′-diisocyanate (HMDI) as hard segment, can quickly recover to 92% of its original tensile strength within 1 h at 50 °C. Due to the better segment movement and looser packing of aromatic disulfide in PCL-HM, the PCL-HM displays better healing properties compared with other types of TPUs (PCL-I, PCL-H, PCL-M, PCL-HM′) prepared in this work. In addition, the fast healing properties of PCL-HM under mild conditions endow it with great application prospects in the field of protective coatings. The successful preparation of PCL-HM also provides a new idea for the synthesis of hard and tough TPU.

有必要开发自修复聚合物，这将显着提高人造材料的安全性和使用寿命。尽管对该领域进行了大量的研究工作，但合成硬而韧的聚合物仍然是一个挑战，这些聚合物在温和条件下具有自修复能力。在这项工作中，我们制造了一种坚硬而坚韧的热塑性聚氨酯（TPU，PCL-HM），PCL-HM 的伤口可以在温和条件下（50°C）快速愈合。综合表征结果表明，PCL-HM 的杨氏模量、拉伸强度和断裂伸长率分别达到 76 MPa、11.8 MPa 和 841%，优于最近报道的 TPU。以芳香族二硫键为动态共价键，聚己内酯二醇（PCL-2000）为软链段制备的PCL-HM，异佛尔酮二异氰酸酯 (IPDI) 和二环己基甲烷-4,4'-二异氰酸酯 (HMDI) 作为硬链段，在 50°C 下 1 小时内可快速恢复至其原始拉伸强度的 92%。由于 PCL-HM 中芳族二硫化物更好的链段运动和更松散的堆积，与其他类型的 TPU（PCL-I、PCL-H、PCL-M、PCL-HM'）相比，PCL-HM 显示出更好的愈合性能在这项工作中。此外，PCL-HM在温和条件下的快速愈合特性使其在防护涂料领域具有广阔的应用前景。PCL-HM的成功制备也为硬韧TPU的合成提供了新思路。由于 PCL-HM 中芳族二硫化物更好的链段运动和更松散的堆积，与其他类型的 TPU（PCL-I、PCL-H、PCL-M、PCL-HM'）相比，PCL-HM 显示出更好的愈合性能在这项工作中。此外，PCL-HM在温和条件下的快速愈合特性使其在防护涂料领域具有广阔的应用前景。PCL-HM的成功制备也为硬韧TPU的合成提供了新思路。由于 PCL-HM 中芳族二硫化物更好的链段运动和更松散的堆积，与其他类型的 TPU（PCL-I、PCL-H、PCL-M、PCL-HM'）相比，PCL-HM 显示出更好的愈合性能在这项工作中。此外，PCL-HM在温和条件下的快速愈合特性使其在防护涂料领域具有广阔的应用前景。PCL-HM的成功制备也为硬韧TPU的合成提供了新思路。