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Mussel-inspired coating of energetic crystals: A compact core–shell structure with highly enhanced thermal stability

2016; Elsevier BV; Volume: 309; Linguagem: Inglês

10.1016/j.cej.2016.10.020

1873-3212

Feiyan Gong, Jianhu Zhang, Ling Ding, Zhijian Yang, Xiaobing Liu,

Luminescence and Fluorescent Materials

Inspired by the strong chemical adhesion of mussels, the polymerization of dopamine was first introduced to coat energetic organic crystals through a simple immersion method. 1,3,5,7-Tetranitro-1,3,5,7-tetraazacyclooctane (HMX) was used as substrate. In-depth characterizations confirmed a compact core–shell formation with a dense graphite-like structure PDA on every HMX crystal. The phase transition temperature of the crystals (β phase → δ phase) was improved by 27.5 °C for HMX enabled in 0.5 wt% PDA. In situ XRD showed that 94.8% of β-HMX was transformed to δ-HMX, whereas only 14.7% of β-HMX was transformed in HMX with 2.1% PDA at 210 °C. The heated HMX/PDA crystals (210 °C, 30 min) retained primary morphology, with intact PDA shell, demonstrating the excellent ability of PDA to prevent thermal damage in energetic crystals. The impact sensitivities of HMX and HMX/PDA were tested by Bundesanstalt für Materialprüfung (BAM) method. No difference between HMX (impact energy: 5.0 J) and HMX/PDA (5.0 J) at room temperature was attributed to the rigid PDA shell, which was benefit for phase transition, but inefficient for reducing sensitivity. After being heated at 200 °C for 30 min, the impact energy of HMX showed a dramatically drop (2.0 J), while that of HMX/PDA unchanged (5.0 J), indicating the increased sensitivity of HMX after thermal damage, and retardation of phase transition is benefit for the safety of polymorph explosives. This work demonstrates the successful application of dopamine chemistry to energetic materials, thereby providing a potential method for the modification of energetic crystals.