Constructing mechanically robust, efficient self‐healing, high‐energy, and recyclable energetic composites by hybrid dynamic lock strategy

It is still a huge challenge to introduce effective crack‐healing ability into energetic composites with a high oxidizer content. In this article, a poly(urea‐urethane) energetic elastomer was prepared by the polycondensation reaction of glycidyl azido polymer (GAP), isophorone diisocyanate (IPDI), and 2‐aminophenyl disulfide (2‐APD). In the poly(urea‐urethane) elastomer structure, the hybrid dynamic lock, including multilevel H‐bonds and disulfide bonds, not only provides abundant dynamic interactions and promotes chain diffusion, but also enhances physical crosslinking density. Such a unique design fabricated the energetic elastomer with robust tensile strength (0.72 MPa), high stretchability (1631%), and outstanding toughness (8.95 MJ/m3) in the field of energetic polymers. Meanwhile, this energetic elastomer exhibited high self‐healing efficiency (98.4% at 60 °C) and heat release (Q = 1750.46 J/g). Experimental and theoretical results adequately explain the self‐healing mechanism, particularly the role of azido units. The high‐solid content (80 wt%) energetic composites based on the energetic elastomer presented outstanding micro‐defect self‐healing (97.8%) and recycling without loss of mechanical performance. The development of smart energetic composites with excellent self‐healing and recyclable ability provides a meaningful way for a wide range of applications in the field of energetic materials.