【摘要】 以RDX(环三亚甲基三硝胺)为基、PS(聚苯乙烯)为粘结剂构成PBX(高聚物粘结炸药)的MD(分子动力学)模拟初始模型.比较分别以1根46链节和2根23链节PS置于RDX(001)晶面上的两种(PBX1和PBX2)模型下的MD模拟结果,发现二者的结构、相互作用能和力学性能均很接近.取PBX2进行5种温度(195,245,295,345和395 K)下的NPT系综、MD模拟系统研究,发现随温度依次升高,各体系中RDX引发键N NO2键的最大键长(Lmax)递增,N–N键连的N与N之间的双原子作用能(EN-N)和内聚能密度(CED)递减,与感度随温度升高而增大的实验事实相一致.综合已有工作,对高能复合材料(如PBX和固体推进剂等)的感度理论研究,建议关注其中易爆燃组分在外界刺激下的结构和能量变化,其引发键Lmax和作为引发键强度度量的双原子作用能(如EN-N),可作为热和撞击感度相对大小的理论判据.更多还原

【Abstract】 A primary model is established for MD(molecular dynamics) simulation for the PBX(polymer-bonded explosives) with RDX(cyclotrimethylene trinitramine) as base explosive and PS as polymer binder.A series of results from the MD simulation are compared between two PBX models,which are represented by PBX1 and PBX2 respectively including one PS molecular chain with 46 repeating units and two PS molecular chains with 23 repeating units each.It has been found that the structures,interaction energies and mechanical properties are basically consistent between the two models.A systematic MD study for the PBX2 is performed under NPT conditions at five different temperatures,i.e.,195 K,245 K,295 K,345 K and 395 K.We have found that the maximum bond length(Lmax) of RDX N–N trigger bond increased,the interaction energy(EN-N) between two N atoms of the N–N trigger bond and the cohesive energy density(CED) decreased when the temperature increased.These results are accordant with the experimental fact that the PBX becomes more sensitive as the temperature increasing.Therefore,we propose to use Lmax of the trigger bond and EN-Nof the two relevant atoms of the easily decomposed and exploded component as theoretical criteria to judge or predict the relative degree of heat and impact sensitivity for the energetic composites such as PBXs and solid propellants.更多还原