Cocrystallization is a promising technique for the design and preparation of new explosives,and the stability of cocrystal is highly concerned by the researchers.In order to make a better understanding of the behavior of cocrystal under the extreme conditions,DFT(density functional theory) calculation is performed to investigate the effect of hydrostatic pressure on geometrical and electronic structures of the cocrystal BTF(benzotrifuroxan)/TNA(2,4,6-trinitroaniline).When the hydrostatic pressure is applied,the lattice constants,volume,density and total energy change gradually except at the pressures of 40 GPa and 79e83 GPa.It is noteworthy that new chemical bonds form when the pressure is up to83 GPa.The band gap of the cocrystal becomes smaller when the pressure is applied,and finally the cocrystal shows a characteristic of metal.The mechanical property of cocrystal is calculated by MD(molecular dynamics) simulation.The results show that the cocrystal has a better ductibility at low temperature,and has the best tenacity at 295 K.
Based on the crystal engineering, six models of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX)/3-nitro-1,2,4-triazol-5-one(NTO) supramolecular explosive were designed. The probable formation of HMX/NTO supramolecular explosive was investigated by the molecular dynamic (MD) method. Interaction between oxygen atoms in HMX and hydrogen atoms in NTO or between hydrogen atoms in HMX and oxygen atoms in NTO were studied by the radial distribution function (RDF). It shows that there are strong hydrogen bonds and Van Der Waals forces between HMX and NTO, in which the hydrogen bonds between oxygen atoms in the NTO and hydrogen atoms in HMX are the main host-guest interactions. The distributions of bond length, bond angle and dihedral angle were simulated by MD. It shows that the structure of HMX is seriously distorted. The binding energies and X-ray powder diffraction (XRD) patterns were calculated on the basis of the final HMX/NTO supramolecular structures. The results show that the binding energies of six supramolecular models are E binding (1 1 1-) >E binding (1 0 0)>E binding (0 2 0)>E binding (random)>E binding (1 0 2-)>Ebinding (0 1 1), and the XRD patterns of six supramolecular models are quite different from pure HMX or NTO. Based on the investigation for growth morphology, binding energies and RDF, the model of HMX supercell substituted by NTO along the (1 1 1-) surface of HMX is easier to form.
采用溶液法制备纳米Bi2O3颗粒,并用P4VP与Al粉自组装,获得分散均匀的纳米铝热剂Al/Bi2O3.利用X-射线粉末衍射(XRD)、扫描电镜(SEM)对其组成和形貌进行表征,运用差示扫描量热仪(DSC)、压力-时间曲线(p-t曲线)分析性能。自组装Al/Bi2O3的反应时间为0.036 s,最大压力为4 729 k Pa,达到最大气体压力的时间为0.162 s,表现出比Al/Fe2O3和Al/Cu O反应更为迅速,产气量更大的性能特点。经过加速老化实验,Al和Bi2O3接触更紧密但无明显团聚;经老化处理,相当于常温下储存15 a时间,Al表面氧化层厚度由3.2 nm增加到4.6 nm,Al/Bi2O3放热量由1 112 J/g逐步降低到606 J/g,Al/Bi2O3用于半导体桥发火时间由37.20 ms增加到50.88 ms,发火能量由0.64 m J增加到1.17 m J.
