A microscale regulation strategy for strong, tough, and efficiently self-healing energetic adhesives

Abstract

In general, robust mechanical properties require a stable strong physical or covalent network inside the polymer, limiting the mobility of molecular chains and the dynamics of physical crosslinks or reversible covalent bonds. Therefore, high healing efficiency at moderate temperature and robust mechanical properties are contradictory, which is difficult to optimize simultaneously. Therefore, this study introduced a new strategy. First, acyl semicarbazides motifs were utilized to endow energetic adhesives with strong and tough mechanical properties. Then, the asymmetric structure was introduced to regulate the hydrogen bonding array density and micro-scale trim the size of the hard domain, thereby improving the hydrogen bonding dynamics and the polymer-chains mobility. Finally, the synthesized energetic polymer adhesive (EPA) exhibited excellent comprehensive ability in terms of mechanical properties, self-healing efficiency, and energy level. Hereafter, the adhesive was further to be used with Al powder for the preparation of the EPA-based energetic composite materials (EPA/ECM), which could be mechanically comparable to commercial non-energetic adhesive-based ECMs. In addition, the high crack-healing efficiency of EPA/ECM indicated that the adhesive possessed strong application potential, which is expected to provide new ideas for improving the safety and service life of energetic composites.