Theoretical Study On Energetic Materials Of TKX-50 And Its Composites

In this paper,molecular dynamics(MD)simulations were performed on 5,5'-Bis(tetrazole)-1,1'-diolate TKX-50/fluoropolymer,TKX-50/?-CL-20 and TKX-50/DNTF composites.The infrared and Raman spectra of TKX-50 and its terahertz spectrum(THz)were studied by density functional theory.Firstly,MD simulations were used to study the interaction of TKX-50 and TKX-50 based high-energy explosives(HE)with fluoropolymers(F2311,F2314,F2611 and F2614).The binding energies,radial distribution functions(RDF),cohesive energy density(CED),mechanical properties and detonation properties of four systems have been calculated simulated.The results show that TKX-50 based HE formed by adding a small number of fluropolymer to the(100)surface of TKX-50 has excellent thermodynamic stability.Fluoromer destroyed the integrity of TKX-50 crystal arrangement,resulting in CED values of the four HE systems are smaller than that of TKX-50.The comprehensive mechanical properties of four HE are better than TKX-50.The theoretical detonation velocity(D)and detonation pressure(P)of four HE systems reduce slightly.Secondly,MD were used to research the compatibility and mechanical properties of TKX-50 with ?-CL-20 and DNTF.By correlating the binding energy,radial distribution function and the cohesive energy density,TKX-50 is compatible with ?-CL-20 and DNTF,and has better compatibility with ?-CL-20.Moreover,hydrogen bonds and van der Waals forces consist in TKX-50/?-CL-20 and TKX-50/DNTF systems.In addition,compared with TKX-50,the elastic modulus of two blend systems are decreased to different degrees,indicating that blend structure can improve the mechanical properties of TKX-50.Thirdly,density functional theory calculations were performed on crystalline TKX-50 under high pressure up to 40 GPa.The intermolecular O…H distances generally decrease with increasing pressures.However,the bond lengths of O-H and N-H change irregularly with the increase of pressure.The predicted strongest Raman peak at 1580 cm-1,involving C-C stretching and NH2 symmetric deformation,which is consistent with the experimental results.Although there is no hydrogen atom in the anion moiety of TKX-50,the deuteration in cation still affects the vibrational mode of anion.For O-H and O-D vibration modes,the Raman shifts decrease due to the strengthening intermolecular hydrogen bond as pressure increasing.The couplings of vibrational modes change with both deuteration and pressure.Finally,GGA-PW91 method was carried out calculates the terahertz spectra(THz)of TKX-50 and deuterium substitutes,and the effect of pressure on the THz spectrum of TKX-50.The results show that TKX-50 has four low frequency peaks and six high frequency peaks at 0?8.0 THz.From the Gaussian view analysis,the absorption peak at 1.17 THz is attributed to N-H…O stretching vibration,and the absorption peaks at 3.87 THz?5.33 THz?and 6.65 THz are attributed to NH3 rocking vibration.It was found that the THz spectrum of TKX-50 takes red shift and the total absorption peaks intensity decreases upon deuteration.To sum up,the THz spectrum of TKX-50 takes blue shift and the total absorption intensity decreases as the pressure increases.