平衡分子动力学模拟硝化纤维/乙醇/乙醚分子包覆的纳米铝粒子的燃烧,ACS Omega

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平衡分子动力学模拟硝化纤维/乙醇/乙醚分子包覆的纳米铝粒子的燃烧
ACS Omega ( IF 3.7 ) Pub Date : 2023-08-28 , DOI: 10.1021/acsomega.3c03547
Yue Chu ₁ , Lei Wang ₁ , Pingan Liu _{1,

2} , Penghua Sui ₁

Affiliation

纳米铝颗粒（ANPs）具有很高的反应活性，但很容易被外部氧化剂失活。为了改善其表面特性，我们用硝化纤维素 (NC)/乙醇/乙醚溶液涂覆 ANP。从涂层到燃烧过程进行了比较讨论。我们的结果表明，NC/乙醇/乙醚在退火的ANPs表面形成致密的涂层，并通过物理和化学吸附钝化ANPs。该涂层可以在低温下阻止活性Al原子和O _{2分子之间的接触。}在点火阶段，NC/乙醇/乙醚涂层可以增加ANPs周围O _{2分子的密度和ANPs的表面温度。}在点火阶段结束时，NC/乙醇/乙醚涂层钝化的ANPs（csANPs）和NC/乙醇/乙醚涂层退火的ANPs（cANPs）表面吸附的O原子数量增加了约60%和50%分别与钝化 ANP (sANP) 相比。由于包覆层的解吸和扩散会暴露更多的反应位点，因此ANPs具有更短的着火延迟和更低的着火温度。根据原子位移的变化，燃烧阶段可分为表面氧化/核心熔化扩散、燃烧向内传播和均匀燃烧三个阶段。NC分子的分解可以增加ANP的燃烧速度、燃烧时间和效率。这样的改进将使ANPs获得更好的储存和燃烧性能，并在含能材料领域发挥更强的作用。

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Combustion of Al Nanoparticles Coated with Nitrocellulose/Ethanol/Ether Molecules by Equilibrium Molecular Dynamics Simulations

Al nanoparticles (ANPs) have high reactivity, but they are easily inactivated by external oxidants. To improve their surface properties, we coat ANPs with a nitrocellulose (NC)/ethanol/ether solution. Comparative discussions are raised from the coating to the combustion process. Our results show that NC/ethanol/ether forms a dense coating layer on the surface of annealed ANPs and passivates ANPs through physical and chemical adsorption. The coating layer can block the contact between the active Al atoms and O₂ molecules at low temperatures. In the ignition phase, the NC/ethanol/ether coating layer can increase the density of the O₂ molecules around the ANPs and the surface temperature of ANPs. At the end of the ignition phase, the number of O atoms adsorbed on the surface of NC/ethanol/ether coating-passivated ANPs (csANPs) and NC/ethanol/ether coating-annealed ANPs (cANPs) increased by about 60 and 50%, respectively, compared with passivated ANPs (sANPs). Since the desorption and diffusion of the coating layer will expose more reaction sites, ANPs have a shorter ignition delay and a lower ignition temperature. According to the change in atomic displacement, the combustion stage can be divided into three stages: surface oxidation/core melting diffusion, combustion inward propagation, and uniform combustion. The decomposition of NC molecules can increase the combustion speed, combustion time, and efficiency of ANPs. Such improvement will enable ANPs to obtain better storage and combustion performance and play a stronger role in the field of energetic materials.

更新日期：2023-08-28

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