Study On The Formulation And Performances Of TNT-Based Low-Energy Spreading Explosives

To solve the problem that the 155mm smoke submunition has high explosive energy and causes damage to the bullet,which affects its safety and effectiveness,this paper designs a low-energy（detonation velocity,detonation heat,detonation volume,etc.）spreading explosives.On the basis of studying the factors affecting the explosive performance（detonation velocity,detonation heat,functional force,etc.）of the spreading explosives,TNT with low explosion energy and small critical diameter was selected as the main explosive of the spreading explosives;Black powder（BP）with lower energy as an energy regulator（additive）for the spreading explosives agent;Phenolic resin（PF）with strong adhesion ability and high softening point was used as the binder for spreading explosives;Molecular dynamics,quantum chemistry,mesoscopic kinetics and other methods were used to simulate a series of low-energy spreading explosives formulations.In order to refine and mix the raw material mixture（TNT,BP）more uniformly,the mixture of TNT and BP was pretreated by a wet ball milling process;Low-energy spreading explosives were prepared by ultrasound-assisted wet mixing-solvent evaporation;Taking the detonation velocity and detonation heat as the criterions and combining the simulation calculation results,the optimal formula of low-energy spreading explosives was determined,and the effectiveness of the low-energy spreading explosives was verified by the performance test and scattering test.The main research contents of this paper are as follows:（1）On the basis of comparing the energy,sensitivity,safety and thermal stability of various explosives,TNT with low explosion energy and small critical diameter was selected as the main explosive of low-energy spreading explosives,and BP with small detonation velocity、detonation heat and critical diameter was used as an additive;The binding energy(E_bind),cohesion energy density（CED）,radial distribution function（RDF）and mechanical properties between phenolic resin（PF）,cis-butadiene rubber（BR）and polyethylene glycol（PEG）and TNT and BP were simulated by molecular dynamics method,and PF was determined to be the best binder;The theoretical calculation shows OB,detonation velocity,detonation heat,detonation volume and detonation temperature of the low-energy spreading explosives.Combined with the technical indicators of detonation velocity and detonation heat of low-energy spreading explosives,the determined optimal formula is:m（TNT）/m（BP）/m（PF）=65/30/5;The theoretical OB is-0.47g,detonation velocity is 4555m/s,detonation heat of low-energy spreading explosive is 3904k J/kg,the detonation volume is417.0L/kg,and the detonation temperature is 2065℃.（2）Using absolute ethanol as the dispersion medium,the TNT and BP mixture was refined and mixed homogeneously by wet ball milling process;Low-energy spreading explosive molding powder was prepared by ultrasonic-assisted wet mixing-solvent evaporation.（3）The performance test of low-energy projectile explosive was carried out:its impact sensitivity and friction sensitivity were 10%and 12%,respectively;The 5s extended flashpoint is 310℃;The flame sensitivity（50%ignition height）is 2.10cm;the electrostatic spark sensitivity is 0%;The thermal decomposition peak temperature and thermal explosion critical temperature were 472.32K and 478.75K,respectively,the activation energy was 220.05 k J/mol,and the Gibbs free energy（ΔG）was 138.28KJ/mol.The gassing amount of vacuum stability test is 0.03ml/g,the gassing amount is less than 2ml/g,and the vacuum stability and internal compatibility are good.The test values of detonation velocity and detonation heat were 4428m/s and 3848k J/kg,respectively.The storage period is not less than 20 years;The spreading verification test proves that the low-energy spreading explosives can make the 155mm smoke submunition open the cabin smoothly,the average initial velocity of the simulated bullet is70m/s,and the average radius of the spreading radius is 100m,which is basically undamaged.It meets the technical requirements that the initial velocity of the bullet（1.0kg）during spread is not less than 60m/s,and the spreading radius is not less than 90m.