Hmx, Of Tatb-based Pbx Along The Mechanical Properties Of Different Crystal Faces And Binding Energy Of Theoretical Research

As the development trend of molecular chemistry penetrating to materials chemistry, study on the structures and properties of composite materials has become a hot scientific field and drawn much attention of chemists and materials scientists. HMX (cyclotetramethylene tetranitramine) and TATB (l,3,5-triamino-2, 4,6-trinitrobenzene) are high explosives widely used with better comprehensive properties. In this dissertation, modern quantum chemistry (QM), molecular mechanics (MM) and molecular dynamics (MD) theoretical methods have been employed to study the influence of the temperature and pressure on the mechanical properties and binding energies of PBX based on HMX and TATB along different surfaces. The effect of high pressure on the crystal structures of HMX has been discussed to predict the relation between the structures and properties.1. The influence of temperature on the mechanical properties and the binding energies of typical explosive, which constructed by F2311 bonded different surfaces of HMX crystal were studied. The results show that there is little difference on the same temperature. The modules of β-HMX and its two composite PBX decrease while the elasticity and inflexibility increase with temperature raise. It is found that the mechanical properties can be effectively improved by blending with fluorine-polymer with small amounts.2. The mechanical properties and binding energies of PBX, which consists of TATB bonded fluorine-polymers along different surfaces, were simulated by MD. The results show that different mechanical properties of PBXs were obtained by putting fluorine-polymers binders parallel to different crystalline surfaces. The effect of improving mechanical properties is found to be (010)≈(100)>(001). The fluorine-polymers (PVDF, PCTFE, F₂₃₁₁, F₂₃₁₄) can be used as binders because strong attract is found between fluorine-polymers and TATB crystal. The order of binding energies for four fluorine-polymers with TATB are as following: PVDF>F2311>F2314>PCTFE. The abilities of different TATB crystal surfaces to combine fluorine-polymers decrease as following: (001 )>(010)>(100). Binding energies are mainly determined by intermolecular hydrogen bond. No parallel and gradual relaxation between the improvement of TATB mechanical properties by blending a series of polymers and binding energies between the polymers and TATB crystal is found. To chosen an optimal and practice binder, it is necessary to consider comprehensively two aspects, i.e. binding energies and mechanical properties.3. Solid density functional theory in combination with the plane-wave potential method...