Molecular Dynamics Simulations Of The Structures And Properties Of Highly Energetic Materials

The present dissertation is devoted to systematic research on the structures and properties of typical propellant of NEPE( nitrate ester plasticized polyether ) by using molecular dynamics (MD) simulation technology. The relationships of constitutions, structures, energies and mechanical properties have been obtained, providing a new research and technology for the sake of formulation design of high energetic and intense propellants. The whole work can be divided into seven parts:1. The applicability of COMPASS force field has been investigated, It is found that COMPASS force field is applicable to NEPE.2. Molecular dynamics simulations have been applied to investigate the mechanical properties of crystal and amorphous structures of nitroglycerine (NG) and cyclotrimethylene trinitranmine (RDX). The results show that the difference of the mechanical properties of crystal and amorphous was due to the structures.3. Molecular dynamics simulations of polyethyleneoxide (PEO), polytetrafuran (PTHF) and their copolymer poly (ethyleneoxide–co–tetrafuran) [P(E–CO–T)] have been performed and the elastic constants, Cauchy pressure, moduli and Poisson's ratios were obtained. It is found that the rigidity and ductibility of PEO are the best and P(E–CO–T) is better than PTHF.4. Molecular dynamics simulations of mechanical properties of different chain units of P(E–CO–T)show that the elastic constants, moduli and Poisson's ratios change little, indicating that the mechanical properties are not much influenced by the amount of the chain units.5. Molecular dynamics simulations have been performed to investigate the mechanical properties of nitroglycerine (NG), triethylene glycol dinitrate (TEGDN) and the mixed nitrate plasticizer composed of NG and TEGDN at the low temperature.The results show that the rigidity was weakened, the ductibility and isotropies were improved by adding TEGDN. Analysis of binding energy and radial distribution function elucidate the interface interaction and its essence between the individual compositions of nitrate plasticizer.6. Molecular dynamics simulation of mechanical properties of the mixtures composed of the prepolymer P(E–CO–T)and one of the four curing agent (IPDI,JQ-1,7900-A,N-100) show that the moduli and Cauchy of the mixture composed of the curing agent 7900-A are the biggest of all. Its rigidity and intensity are stronger than those of the others, and its ductibility is also fine.7. Multi-scheme, all-around explorations and investigations were carried out for the four complicated systems of the typical NEPE propellants composing of multi-constitutions. The results are consistent with those of the above mixtures.In summary, molecular dynamics simulation technology has been applied to calculate and simulate the relations between the structures and properties of the NEPE propellants. The work possesses theoretically and practically weightiness. In particular, the MD simulation on the mechanical properties of NEPE propellants is a breakthrough, providing a new effective technology for the formulation design of NEPE propellant.