Study On The Performance Of Nitrogen Heterocyclic Azole Low Eutectics And Melt-cast Explosives

Melting point is the most basic element to judge whether energetic compounds can become melt-cast carriers,so how to reduce the melting point of energetic compounds is one of the research focuses of melt-cast carriers nowadays.Low eutectic is a mixture of two or more substances formed with low melting point,which is an effective means to reduce the melting point.However,in recent years,the reports mainly focus on the synthesis and characterization of low eutectics,and there are fewer studies on the formation mechanism and interactions between components of low eutectics.Nitrogen heterocyclic azole compounds are gradually gaining attention due to their advantages of high enthalpy of generation,low susceptibility and good detonation performance.In this paper,molecular dynamics was used to study the performance of nitrogen heterocyclic azole low eutectics as well as melt-cast explosives to provide directions for subsequent research on melt-cast carriers.The main work in this paper is as follows:(1)MDNI/MTNP and MTNI/MTNP mixtures with different mass ratios were constructed to study the effects of mass ratio and type of components on the formation and stability of low eutectic,and MDNI/MTNP mixtures were prepared experimentally.Molecular dynamics simulations were carried out in the temperature range of 240-480 K.The specific volume,non-bonded energy,diffusion coefficient,binding energy and radial distribution function(RDF)of MDNI/MTNP and MTNI/MTNP mixtures were analyzed.The results show that the melting point values of the MDNI/MTNP mixtures obtained using specific volume,non-bonded energy and diffusion coefficient are in good agreement with the experimental values.The MDNI/MTNP mass ratio of 60/40(Mixture A4)and the MTNI/MTNP mass ratio of 50/50(Mixture B5)have the lowest melting point values and are more likely to form low eutectic.Moreover,the binding energy of the Mixtures A4 and B5 is the largest,the intermolecular interaction is stronger,the system is more stable and the detonation performance is better.When the mass percentage of MTNP exceeds 40%,the binding energy of the MTNI/MTNP mixture is greater than MDNI/MTNP,the interaction is stronger and the system is more stable.(2)The effects of structural similarity and mass ratio on the formation and stability of low eutectic were investigated by molecular dynamics methods in the temperature range of240-480 K.The specific volume,non-bonded energy,binding energy and RDF of ADNP/DNP and MTNP/ATNP mixtures with different mass ratios were analysed,and the results showed that the structural similarity and suitable mass ratio of the components contributed to the formation of low eutectic.The variation of specific volume and non-bonding energy with temperature shows that ADNP/DNP with a mass ratio of 40/60(Mixture C6)and MTNP/ATNP with a mass ratio of 60/40(Mixture D4)have the lowest melting point values and are more likely to form low eutectic.Mixture C6 and Mixture D4 have the highest binding energy,stronger interactions and more stable systems.Compared to the ADNP/DNP mixture,the MTNP/ATNP mixture has a higher structural similarity of the components and a greater binding energy.Combined with the RDF analysis,the MTNP/ATNP mixture has a stronger interaction between the components and a more stable system,and the MTNP/ATNP mixture has better detonation properties.(3)Using HMX as the high-energy component and nitrogen heterocyclic azole low eutectics as the carrier,the melt-cast systems with different mass ratios were constructed,and the binding energy,RDF and detonation performance of the melt-cast systems were studied by MD method.The results showed that the binding energy of HMX/(MTNP/ATNP)system was the largest,the strongest interaction and the most stable system when the mass percentage of HMX was certain.The RDF analysis showed that for the HMX/(MDNI/MTNP),HMX/(MTNI/MTNP)and HMX/(MTNP/ATNP)systems,the interaction between HMX and MTNP was stronger;for the HMX/(ADNP/DNP)system,the interaction between HMX and ADNP was stronger.The detonation performance of the HMX/(MTNP/ATNP)system is superior compared with the other three systems,indicating that the MTNP/ATNP low eutectic is expected to be used as a carrier to form a melt-cast explosive with HMX.