Investigate Of Performance And Interaction Between Components Of High Energy Hybrid System

In the field of both military and industrial,the high-energy hybrid system was obtained by mixing a variety of energetic materials or to add specific additives and it have been widely applied due to the elemental energetic materials are far from satisfy the needs in reality.Solid Rocket Propellant?SRP?is one kinds of typical high-energy hybrid system with the diversified and complex formula.What follows is the complication of the interaction between the components.The interaction between different components can have a significant impact to performance of SRP.Furthermore,in order to further improve the performance of the high-energy hybrid system,the holistic performance can be improved by enhancing the properties of partial components.This thesis studies from the following two aspects:The interaction between server common oxidants?RDX,HMX,CL-20,AP and ADN?and Al was developed based on Quantum Chemical?QC?calculation method,and for the first time,the interaction of ternary system?RDX-AP/Al?was studied.On the other hand,the construction and stability of the cocrystal complexes were formed by two kinds of energy-containing ionic salts?AP,ADN?and PDO were studied.Meanwhile,the performance of cocrystal complexes was investigated.The main research contents are as follows:1)The interaction between three kinds of nitramine compounds?RDX,HMX and CL-20?and Al?1 1 1?surface were investigated by using density functional theory?DFT?.The adsorption and decomposition mechanisms of them on Al?1 1 1?surface were studied respectively from adsorption structure,adsorption energy,charges transfer,density of states,electron density difference and initial decomposition path.The results show that physical and chemical interactions exist simultaneously in the adsorption process accompanied by the charges transfer that include Al loss electrons and adsorbed molecules obtained electrons.Because of the strong force between Al and O atoms,the decomposition way of molecules has changed from rupture of N–NO₂ to rupture first of N–O.After decomposition,the surface of Al was oxidized by decomposition products to form Al–O bonds and Al–N bonds.The degree of decomposition of molecules is not only related to its own properties but also depends on the relative area of occupies on the Al?1 1 1?surface.The larger the relative area occupied,the easier it is to decompose.The activation energy required for the initial decomposition of the three molecules was 0.45,0.57,and 0.54 eV,respectively.The energy barriers are relatively low,and the metal Al has a catalytic effect on its decomposition.2)The surface model of Al?1 1 1?was established and optimized.The adsorption and decomposition of two kinds of energy-containing ionic salts?AP,ADN?on Al?1 1 1?surface was investigated based on DFT.A ternary system model was built to study the interaction between RDX-AP and Al.There is violent decomposition of AP and ADN on Al?1 1 1?surface.The main decomposition way of AP is break of Cl–O,and forming hypochloric acid.For ADN,on the other hand,is the transfer if H atom and rupture of N–N,N–O and generate gas molecules such as NH₃,NO₂,and NO,and so on.Physical and chemical interactions exist simultaneously in the adsorption process,with Al loss electrons and adsorbed molecules obtained electrons.The activation energy for the initial decomposition of AP and ADN were0.36 and 0.31 eV,respectively,which were both lower than that nitramine molecules and easier to decompose than them.However,the Gibbs free energy??G?of AP and ADN were lower than nitramine molecules when reached the stable configuration.There is no obvious difference in decomposition ways between ternary system and binary system.But the activation energy required for the initial decomposition of molecules in ternary system is higher than that in binary system?1.38 eV>0.33 eV?,and the?G released after decomposition to a stable configuration is also higher than that in binary system?|-3.43 eV|>|-0.75 eV|?.It indicates that the ternary system was more stable than the binary system and the former could release more energy once it decomposed.3)The cocrystal of two kinds of energy-containing ionic salts were researched.Firstly,under the calculation level of B3LYP//6-311++G**,the different configurations were optimized to obtain their stable structures.The location,type and intensity of interaction between molecules were analyzed through atom in molecular?AIM?and reduced density gradient?RDG?analyses.The results show that there are hydrogen bonds and van der Waals interactions between AP/ADN and PDO.Hydrogen bond types are mainly N–H···O,Cl–H···O and C–H···O,which is conducive to the formation cocrystal of AP/PDO and ADN/PDO.The electrostatic potential?EPMs?analysis showed that the sensitivity of cocrystal complex was decreased and its safety performance was improved.Then the formation of two kinds of cocrystal models under different conditions was studied by means of molecular mechanics?MM?,and their mechanical properties and oxygen balance?OB?were analyzed.The results indicated that the 3:2 model of the AP/PDO cocrystal has a larger binding energy at 298 K and better stability,and the oxygen balance was+1.4%;the 2:1model of the ADN/PDO cocrystal has a larger binding energy at 318 K,and better stability,and the oxygen balance was 0.Finally,the crystal structure and morphology of cocrystal complexes were predicted under the optimal conditions.