Preparation And Properties Of MTNP-based Multicomponent Eutectic

Nowadays,2,4,6-trinitrotoluene(TNT),the liquid carrier of traditional molten-cast explosives,can no longer meet the requirements of modern weapons due to its low density,low energy level,poor mechanical properties,and high toxicity.However,the synthesis of new lowmelting explosives has the disadvantages of difficult process,long cycle and low efficiency.Hence,the preparation of energetic eutectic is an important method to solve the above problems.In this paper,three binary eutectic formulations(MTNP/TNAZ,MTNP/PETN and MTNP/DNTF)were prepared based on a new melt-cast explosive of 1-methyl-3,4,5-trinitropyrazole(MTNP).The surface elements,microstructure,sensitivity and energy properties of the three binare lowest eutectics were characterized by EDS,XRD,IR,XPS,thermodynamic analysis,TG-MS analysis,mechanical sensitivity test,5 s explosion temperature test and detonation performance calculation.On this basis,a ternary energetic eutectic(MTNP/DNTF/DNAN)was prepared and its properties were characterized,and its properties were compared with those of binary energetic eutectic.The main research are as follows:(1)Preparation and characterization of MTNP/TNAZ lowest eutectic mixture.MTNP/TNAZ eutectic mixtures with different molar ratios were prepared by solvent/non-solvent method,and the molar ratio of the lowest eutectic mixture was obtained by DSC-phase diagram method.Then,the structure and properties of the lowest eutectic mixture were characterized.It was found that there is only weak intermolecular force between MTNP and TNAZ molecules,and no chemical action occurs to generate new chemical bonds.The melting point of the produced lowest eutectic mixture was within the optimal melting point range of the eutectic mixture.The detonation parameters of the lowest eutectic mixture for MTNP/TNAZ are calculated: the detonation velocity,detonation heat,detonation pressure and detonation temperature are8704.96 m/s,-5956.22 k J/kg,34.32 GPa and 4092.44 K,respectively.In the experiments,the impact sensitivity(H50)is 67.89 cm,the friction sensitivity is 64%,and the 5 s explosion temperature is 267.8°C.(2)Preparation and characterization of MTNP/PETN lowest eutectic mixture.MTNP/PETN eutectic mixtures with different molar ratios were prepared by solvent/non-solvent method,and the molar ratio of the lowest eutectic mixture was obtained by DSC-phase diagram method.Then,the properties of the MTNP/PETN lowest eutectic were explored.It was found that no new chemical bonds or chemical groups were generated between MTNP and PETN molecules,and only a certain intermolecular force existed,indicating that MTNP and PETN were well mixed.The melting point of the obtained MTNP/PETN lowest eutectic mixture(86.87°C)is slightly higher than that of TNT(80.3°C),which can well meet the melting point requirement.The theoretical detonation parameters were calculated: the detonation velocity is 8377.23 m/s,the detonation heat is-5700.59 k J/kg,the detonation pressure is 31.54 GPa and the detonation temperature is 3946.90 K.The experimental results show that the impact sensitivity(H50)is50.31 cm,the presence of MTNP has no effect on the friction sensitivity of PETN(100%),and the 5 s explosion temperature is 225°C.(3)Preparation and characterization of MTNP/DNTF lowest eutectic mixture.MTNP/DNTF eutectic mixtures with different molar ratios were prepared by solvent/non-solvent method,and the molar ratio of the lowest eutectic was obtained by DSC-phase diagram method.Then,the performance of the MTNP/DNTF lowest eutectic was tested.The results show that there were no new chemical bonds or chemical groups between MTNP and DNTF molecules,the compatibility between the raw materials is good,but there is a certain intermolecular force between them.The melting point of the MTNP/DNTF lowest eutectic mixture(78.94?)is close to that of TNT.The calculated detonation velocity of the lowest eutectic is 8845.44 m/s,the detonation heat is-5969.10 k J/kg,the detonation pressure is 35.28 GPa,and the detonation temperature is 4347.79 K.In the experiments,its impact sensitivity is 62.03 cm,friction sensitivity is 76%,and the 5 s explosion temperature is 263°C.(4)On the basis of the above research,the MTNP/DNTF/DNAN ternary eutectic compound was prepared with solvent evaporation method by adding 10% insensitive explosive DNAN to the MTNP/DNTF minimum eutectic.The microscopic morphology,structure,mechanical sensitivity and energy properties of the eutectic samples were characterized.And the results show that the surface of the MTNP/DNTF/DNAN eutectic mixture is smoother with less solidphase aggregation and shrinkage voids.There is no chemical action between MTNP,DNTF and DNAN to generate new chemical bonds or chemical groups,and only a certain intermolecular force exists.The melting point of the ternary eutectic MTNP/DNTF/DNAN is(73.4°C).The calculated detonation velocity of the ternary eutectic is 8505.82 m/s,the detonation heat is-5702.26 k J/kg,the detonation pressure is 31.97 GPa,and the detonation temperature is 4144.28 K.The measured impact sensitivity is 81.3 cm,and the friction sensitivity is reduced to 0%.The MTNP/DNTF/DNAN ternary eutectic mixture has a moderate melting point,high energy output and low sensitivity,indicating that it has broad application prospects in molten-cast explosives.