Multiphase hydrogen bonding strategies room temperature self-healing, recyclable polyurethane elastomers for applications in flame retardant materials

Novel elastomers offer new opportunities to develop multifunctional materials in terms of combining mechanical strength, room-temperature self-healing properties and recyclability. However, self-healing polymers have high mechanical strength at high internal cross-linking density, but restrict the movement of molecular chain segments leading to reduced self-healing efficiency. The presence of microphase-separated structures makes the polymers poorly efficient for repair at room temperature. In this paper, a multiphase hydrogen bonding (H- bonding) strategy is used to introduce an aliphatic ring into the system to form a repeating unit with the hard segments, as well as a bis-benzene ring structure with a methylene linkage to disrupt the crystallization of the hard domains. Specifically, PUPI-M2I3 2 I 3 has a mechanical tensile strength of 17.93 MPa, an excellent tensile ratio of 1109.88 %, the sample can recover 95.93 % at room temperature after 24 h of fracture and stretching, with excellent room temperature self-healing performance and recyclability. Meanwhile, the self-healing flameretardant material based on PUPI-M2I3 2 I 3 is developed by comprehensive consideration, which opens a new way for the research and development of flame-retardant materials.