Room-Temperature Self-Healing Ablative Composites via Dynamic Covalent Bonds for High-Performance Applications

High-performance ablative composites demonstrate promising applications in the field of aerospace for thermal protection. In this study, the preparation of flexible thermal ablative composites with fast room-temperature self-healing properties was reported. First, a facile route to synthesize transparent and self-healing PDMS-polyurethane (PU) elastomers was proposed. Results showed that the room-temperature self-healing efficiency of PDMS-PU elastomers can reach as high as 92.9% for 3 h. Low-field NMR analysis indicated that the mobility of molecular chains plays a critical role in determining the self-healing efficiency of PDMS-PU elastomers. Afterward, polymeric thermal protection composites which can be self-healed at room temperature within 24 h were prepared. Results indicated that the self-healed composites can withstand flame erosion at nearly 1300 °C. This work provides insights into expanding the application of self-healing materials in the aerospace industry, where heat ablation and the intactness of thermal protection systems are both primary concerns.