The thermosetting polyurea possessed high tensile strength and elongations at break due to strong intermolecular interactions, but their recycling and reprocessing remains a great challenge, especially at a temperature below 100 °C. Herein, the novel crosslinked polyurea with excellent recycling and reprocessing properties has been prepared by introducing the Diels-Alder dynamic covalent bond. The chemical structure, thermal mechanical properties and reprocessing performance of the crosslinked polyurea were investigated. The prepared polyurea has low relaxation time of ∼4 min at 80 °C for facile reprocessing. The tensile strength and elongation at break of crosslinked polyurea could reach 15.24 MPa and 529.2%, respectively, and its mechanical properties remain almost unchanged even after repeated processing. This work has realized the recycling of crosslinked polyurea, which has huge potential applications in environmental protection and recycling of waste plastics.

由于分子间相互作用强，热固性聚脲具有高拉伸强度和断裂伸长率，但它们的回收和再加工仍然是一个巨大的挑战，尤其是在低于 100°C 的温度下。在此，通过引入狄尔斯-阿尔德动态共价键制备了具有优异回收和再加工性能的新型交联聚脲。研究了交联聚脲的化学结构、热力学性能和再加工性能。制备的聚脲在 80°C 下具有约 4 分钟的低弛豫时间，便于再加工。交联聚脲的拉伸强度和断裂伸长率分别达到15.24 MPa和529.2%，即使经过反复加工，其力学性能也几乎保持不变。