MD Simulation Of RDX/TNT-based Casting Explosives With Polyurethane Urea And Polyurethane Thermoplastic Elastomer Composite Systems

With the increasingly complex environment of the contemporary battlefield,the safety requirements of fire explosives are particularly important for the battlefield,in order to achieve a better match between the sensitivity and energy of explosives,the energy binder and high energy explosives will generally be mixed in proportion,this method is currently the simplest and most convenient way to get better explosives.Casting explosives are a more important type of mixed explosives in the battlefield,although the production process is simpler and more widely used than other explosives,but there will still be some problems and defects,brittleness is relatively large,poor mechanical properties are two significant shortcomings.Therefore,this paper enhances the modification of casting explosives by adding polyurethane urea thermoplastic elastomer and polyurethane thermoplastic elastomer,improves its compatibility and mechanical properties,and can be widely used in battlefields.Through molecular dynamics simulation(MD)method,the thermal stability configuration of the high-energy system of each component obtained by the simulation was calculated,and the thermal interaction energy,radial distribution function,and cohesion energy density between the components were calculated,based on which the correlation compatibility between the components was considered.The relevant mechanical properties(modulus of elasticity,elastic coefficient,Cauchy pressure,etc.)of the material are calculated by the static mechanical matrix parameters,and the relationship between the components and structural properties of complex systems is studied on the theoretical basis.So this article will study the regularity and reveal some progressive laws.The main research contents are as follows:Using MS software,homopolymer polymerization is used to construct molecular chains of three polymers: straight-chain polyurethane urea thermoplastic elastomer,three-arm polyurethane thermoplastic elastomer,and six-arm polyurethane thermoplastic elastomer structure.The molecular weight of the three polymer molecular chains is adjusted appropriately according to the different composite systems,and each molecular chain structure repeats 10 units.When calculating the relevant mechanical properties,the Forcite module under MS software is first used to optimize the structure of the three polymer molecular structure models just constructed,so that they can achieve the state of structural convergence,and perform kinetic relaxation so that the structure can reach the energy minimization standard.Secondly,the three molecular chain structures and the casting explosive are placed in a periodic box with periodic boundary in a certain proportion,and under different temperature conditions,the MD simulation is carried out,and the relevant data analysis is obtained,the specific process is: the constructed direct chain polyurethane urea thermoplastic elastomer,three-arm polyurethane thermoplastic elastomer,six-arm polyurethane thermoplastic elastomer are blended with a certain proportion of casting explosive.The structural optimization of the three blended composite structures is obtained by MD simulation to obtain the corresponding mechanical property parameters,and the compatibility and binding energy between them are analyzed,and the relevant engineering modulus(Young’s modulus,bulk modulus,shear modulus)can be analyzed to obtain better mechanical properties,the addition of polymer has a certain enhancement modification effect,and the data of binding energy,radial distribution function and other related parameters are analyzed,and the compatibility between them can be obtained.And it can be seen that the intermolecular mainly hydrogen bonding is strong,through the addition of these three polymers,the toughness of pure components of melting and casting explosives has also been improved,there is better processing and formability,to a certain extent,to achieve high energy and low feeling,but also improve its poor mechanical properties,brittleness and other defects,can better realize the enhanced modification of melting and casting explosives.