Self-healed microcracks in polymer bonded explosives via thermoreversible covalent bond and hydrogen actions

• Published in: Defence technology Vol. 28; pp. 183 - 194
• Main Authors: Li, Yu-bin, Zhao, Xu, Luo, Ya-jun, Yang, Zhi-jian, Pan, Li-ping, Zeng, Cheng-cheng, Lin, Cong-mei, Zheng, Xue
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2023; KeAi Communications Co., Ltd
• Subjects: Diels-alder (DA) bonds; H-bond; Polymer bonded explosives; Self-healing polymers; Self-healing polymers; Diels-alder (DA) bonds; H-bond; Polymer bonded explosives
• ISSN: 2214-9147; 2214-9147
• DOI: 10.1016/j.dt.2022.11.014

Polymeric materials used for the polymer bonded explosive (PBX) or other energetic composite materials (ECMs) that simultaneously possess excellent mechanical properties and high self-healing ability, convenient healing, and facile fabrication are always a huge challenge. Herein, self-healing linear polyurethane elastomers (PTMEG2000-IPDI-DAPU, denoted as 2I-DAPU) with high healing efficiency and mechanical properties were facilely fabricated by constructing reversible covalent bonds and dynamic hard domains into polymer chains. Furthermore, a TATB-based PBX using as-prepared 2I-DAPU polymer as the binder was constructed, disclosing an excellent self-healing property to heal cracks generated during fabrication, transportation and storage. The damage healing manner of such a PBX sample was investigated by means of prefabricated damage through mechanical load, heal treatment via heating at high temperature, and CT-scanning the inner structure and mechanical property characterization via Brazilian test. The self-healing mechanism of internal damage in PBX was preliminarily explored. We propose that this 2I-DAPU binder with Diels-Alder bonds could generate plentiful active surface groups resulting from damage and drive self-healing at fitting temperature and increase the slightly packed hard phase via incorporating a small amount of hydrogen bonds. This work may offer a novel strategy for improving mechanical property and healing ability in the field of self-healing material which could help expand its applications with enhanced versatility in mechanical-enhanced functional materials.