Development of robust and rapid self-healing polymers for the repair of microcracks in energetic composite materials

Adhesives with exceptional toughness and self-healing properties are vital for the practical application of energetic composite materials (ECMs). However, the majority of self-healing polymers used in ECMs lack sufficient toughness. In this study, we address this challenge by incorporating asymmetric alicyclic and bent biphenyl ring structures into the hard domain units of polymers. The synthesized PUDS-3 films exhibit a remarkable toughness of up to 20.93 MJ·m−3, recovering over 90% of this toughness within just 20 min after a complete fracture. This behavior results from the synergistic interaction between dynamic disulfide and hydrogen-bonding mechanisms during the restructuring process. Furthermore, elevated temperatures led to a rapid decrease in the relaxation modulus and characteristic relaxation time of the PUDS samples, effectively accelerating crack healing. Both experimental measurements and molecular dynamics simulations demonstrated that a higher hard segment content in the adhesive corresponded to increased strength in the interfacial interaction with 1,3,5-trinitro-2,4,6-triaminobenzene (TATB). Upon accidental mechanical damage, the cracked ECMs displayed significant and efficient self-healing capabilities within 24 h at 60 °C. The utilization of these self-healing and highly toughness adhesives hold promising prospects for enhancing the safety and longevity of ECMs.