摘要
采用附着能(AE)模型、分子动力学(MD)方法,分别预测了1,1-二氨基-2,2二硝基乙烯(FOX-7)在真空条件下和八种不同溶剂中(二甲基亚砜(DMSO)、丙酮、甲醇、N-甲基吡咯烷酮(NMP)、N,N-二甲基乙酰胺(DMAC)、乙酸乙酯(EA)、水(H_(2)O)、DMSO/H2O(V/V=2/1))的晶体形貌,计算了溶剂与晶面之间的相互作用能、溶剂影响下的附着能,得到了模拟晶习及其长径比值。为对比研究,同时采用自然降温法在以上八种溶剂的FOX-7饱和溶液中进行重结晶,得到了不同形貌的晶体。预测结果表明:真空下FOX-7晶体具有六个重要生长晶面:(101)、(101)、(011)、(002)、(110)、(111),其中(011)面的面积占比最大,为影响FOX-7晶体形态最重要的晶面。溶剂对晶体长径比的影响程度大小顺序为:DMSO<DMSO/H_(2)O<丙酮<甲醇<NMP<DMAC<EA<H_(2)O。实验得出FOX-7在DMSO、甲醇及DMSO/H_(2)O溶剂中重结晶得到的晶体为块状;在丙酮、NMP中为长条棒状;在DMAC、H_(2)O中为针状;在EA中为片状。理论预测结果与实验结果具有较好的一致性,证明利用AE模型模拟FOX-7的晶习可为结晶实验提供较好的指导作用。热性能研究表明:晶体的表面形貌和内部缺陷会影响FOX-7的相变温度和热分解温度;晶体缺陷越少,α→β相变转晶温度越高;晶体长径比越大,粒径越小,第一分解温度越低。
The attachment energy(AE)model and molecular dynamics(MD)methods were used to predict the crystal morphology of 1,1-diamino-2,2-dinitroethylene(FOX-7)under vacuum condition and in eight solvent systems including dimethylsulfoxide(DMSO),acetone,methanol,N-methylpyrrolidone(NMP),N,N-Dimethylacetamide(DMAC),ethylacetate(EA),water(H_(2)O),and DMSO/H_(2)O(V/V=2/1).By calculating the interaction energies between the solvent and crystal plane,and the attachment energies under the influence of the solvent,the simulated crystal habit and its aspect ratio were obtained.The results show that FOX-7 crystal has six important growth planes under vacuum:(101),(101),(011),(002),(110),(111).Among them,the area of(011)plane accounts for the largest proportion,which is the most important crystal plane affecting the crystal morphology of FOX-7.The influence degree of solvent on the aspect ratio of crystal is in the following order:DMSO<DMSO/H_(2)O<Acetone<methanol<NMP<DMAC<EA<H_(2)O.By recrystallization experiments,FOX-7 crystals have a bulk-like shape in DMSO,methanol,and DMSO/H_(2)O;a rod-like shape in acetone and NMP;a needle-like shape in DMAC and H_(2)O;a flake-like shape in EA.The theoretical prediction results are in good agreement with the experimental results,which proves that the simulation of the crystal habit of FOX-7 based on the AE model can provide better guidance for the crystallization experiment.Results in thermal properties show that the crystal surface morphology and internal defects affect the phase transition tem-perature and thermal decomposition temperature of FOX-7.The fewer the crystal defects,the higher the α→β transformation tem-perature.The larger the crystal aspect ratio,the smaller the particle size,and the lower the first decomposition temperature.
作者
樊思琪
顾晓飞
段晓惠
李洪珍
FAN Si-qi;GU Xiao-fei;DUAN Xiao-hui;LI Hong-zhen(Institute of Chemical Materials,China Academy of Engineering Physics,Mianyang 621999,China;College of Materials Science and Engineering,Southwest University of Science and Technology,Mianyang 621000,China)
出处
《含能材料》
EI
CAS
CSCD
北大核心
2021年第11期1132-1141,I0009,共11页
Chinese Journal of Energetic Materials
基金
国家自然科学基金资助(21875231)。
