| Aimed warhead with efficiency and destruction has become increasingly more discriminating in regard to boosters used in explosive network. On the one hand, the critical diameter of boosters should be in submillimeter level usually. One the other hand, charging accuracy need for a high precision and charging method should be simplicity. In view of these two requirements, booster formulations used in the small explosive network were designed. Charge molding method and performance test were also researched. The research results have practical significance on aimed warhead to be miniaturized.Firstly, by means of molecular dynamics software(MS), rheological and thermal decomposition properties of the formulation, which acted as the charge in the small size explosive network groove, was confirmed. With HTPB and GAP as binder, respectively, binding energy of GAP and CL-20 is more than HTPB and CL-20. Moreover, according to theoretical detonation velocity and measured viscosity, when the solid content of main explosive(CL-20) was determined as 82%, the particle size ratio of large and small CL-20 is 7:1 and the mass ratio of them is 2:1, comprehensive rheological factor of explosive slurry is maximum of all. With DOA and TA as plasticizer, respectively, apparent activation energy and critical explosion temperature of formulation with TA improved obviously. When span 80, tween 80 and silicone oil were used as surfactant, respectively, comprehensive rheological properties of formulation with span 80 are excellent of all. The optimum booster formulation is as follows. CL-20(140μm in size), CL-20(20μm in size), GAP, TA, Span 80, trimethylolpropane, toluene diisocynate and dibutyltin dilaurate is 54.7wt%, 27.3wt%, 14wt%, 1.5wt%, 0.2wt%, 0.2wt%, 1.5%wt, and 0.6%wt, respectively.Secondly, witness plate temperature and pressure were confirmed by viscosity property of explosive slurry. Based on crosslinking point in curing process of GAP and CL-20 according to MS software and non-isothermal test of DSC, isothermal curing temperature of substrate after explosive slurry charged in the groove was built. The viscosity of explosive slurry was tested at 20℃, 40℃, 60℃, 80℃ and 90℃. The viscosity test results show that the viscosity of explosive slurry is minimum at 80℃ in different curing time. By controlling procuring time of explosive slurry and charging the explosive slurry in the groove, groove charge does not overflow when the procuring time is 50 min. By the density test of groove charge under different pressure, the density of groove charge can reach 90% theoretical maximum density(TMD)when the charge pressure is 0.9 t. The final micro injection charging process is as follows. The explosive slurry should be used at ambient temperature. The witness plate temperature, procuring time, charge pressure, pressing time serves as 80℃, 50 min, 0.9t and 10 s, respectively.Thirdly, the quantity of crosslinking point in the process of GAP and CL-20 curing was simulated by MS at 30℃, 60℃, 90℃ and 150℃. It is concluded that curing effect is best when the temperature is 60℃. Initial curing temperature(41℃), the best curing temperature(51℃) and curing end temperature(80℃) were introduced by DSC non-isothermal test and simulation results are good agreement with experiment. Kinetic parameters of GAP and CL-20 curing were studied by DSC non-isothermal test and the relationship of temperature, time and viscosity of formulation was predicted by curing kinetic equation of GAP and CL-20 obtained by Dual Arrhenius model. The results indicate that curing reaction order of GAP and CL-20 is 0.865 and activation energy is 39.788 kJ/mol. The viscosity predictions by curing kinetic equation coincide well with experimental results of GAP and CL-20 under different temperatures and time period.Finally, XRD, mechanical sensitivity, shock sensitivity, energy output and thermal decomposition properties of GAP/CL-20 slurry were tested and analyzed. In addition, propagation reliability and detonation velocity of cured and charged substrate were tested. The results demonstrate that when the process temperature is 80℃ and curing temperature is 60℃ of GAP/CL-20, the crystal type of ε-CL-20 is not changed to others. The impact and shock sensitivity of GAP/CL-20 composite explosive is lower than that of raw CL-20 and traditional booster explosive PBXN-5. In the aspect of energy output, the steel dent of GAP/CL-20 composite explosive is deeper than that of PBXN-5. Compared with raw CL-20, the activation energy and critical explosion temperature is higher. Moreover, through the propagation test at different groove sizes when the CL-20 solid content of GAP/CL-20 composite explosive is 82%, it can propagate the detonation waves successfully in the groove at 0.6 mm×0.6 mm. When the charge density in the groove is 1.68 g/cm3(90%TMD), its detonation velocity can reach 7290 m/s. |
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