The particle size of explosives plays a key role in the short-duration pulse shock initiation, and explosives with small grain size and large specific surface area (SSA) generally have preferable sensitivity properties. We have constructed a high-throughput microfluidic recrystallization platform, aiming to prepare ultrafine pentaerythritol tetranitrate (PETN, C(CH₂NO₃)₄) via a precisely controllable solvent/nonsolvent recrystallization process. Through this platform, the recrystallized PETN was produced with a particle size of about 2 μm, and its SSA was above 70-fold that of the raw PETN. The X-ray diffraction results indicated that the raw and microcrystalline PETN had a similar diffraction spectrum. The thermal analysis demonstrated that compared with the raw PETN, the microcrystalline PETN revealed better decomposition performances. Importantly, the short-duration pulse shock initiation sensitivity of microcrystalline PETN pellets was evaluated when subjected to an exploding foil initiator. The shock initiation threshold results were as follows: 50 % initiation voltage U (50 %)=1332 V, the corresponding capacitor storage energy was 195.2 mJ. Furthermore, the calculated shock pressure and shock duration imparting to the pellets were 9.61 GPa and 12.53 ns respectively, corresponding to the 3162 m/s threshold velocity. Finally, the enhanced sensitivity during the shock-to-detonation transition was further explained with the hot spot-based mechanism.

中文翻译：

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微流控重结晶平台制备的微晶PETN及其性能表征

炸药的粒径在短时脉冲冲击起爆中起关键作用，小粒径和大比表面积（SSA）的炸药通常具有较好的敏感性。我们构建了一个高通量微流控重结晶平台，旨在制备超细季戊四醇四硝酸酯（PETN, C(CH ₂ NO ₃ ) ₄) 通过精确控制的溶剂/非溶剂重结晶过程。通过该平台，生产出粒径约为2 μm的重结晶PETN，其SSA是原始PETN的70倍以上。X 射线衍射结果表明原始和微晶 PETN 具有相似的衍射光谱。热分析表明，与原料PETN相比，微晶PETN显示出更好的分解性能。重要的是，当受到爆炸箔引发剂时，评估了微晶 PETN 颗粒的短时脉冲冲击引发敏感性。冲击起始阈值结果如下： 50 % 起始电压U(50 %)=1332 V，对应的电容储能为195.2 mJ。此外，计算出的冲击压力和冲击持续时间分别为 9.61 GPa 和 12.53 ns，对应于 3162 m/s 的阈值速度。最后，用基于热点的机制进一步解释了冲击到爆炸转变过程中增强的敏感性。