Preparation For Nano-composite Energetic Materials

In order to gain the high energy, insensitive, and low delicate new nergetic materials, thisstudy combining sol-gel, choose porous Fe₂O₃gel as templates, by supercritical fluidtechnology prepared the nano nergetic materials, and attempt to join the sub-micron B powderto improve the sensitivity performance and thermal decomposition performance.In this article, 90% RDX subject explosives and 2% B powder were dissolved into acertain concentration of the precursor solution, which chose porous Fe₂O₃gel as templates,and then the wet gel crystallized by supercritical fluid drying technology, so as to obtain thecorresponding nano-composite energetic materials. The porous aerogel template Fe2O3wasprepared in the experiments, mainly through adjusting the precursor concentration, theaddition amount of epoxy propane, the time of aging, the supercritical fluid drying conditions.Combined with characterization methods such as scanning electron microscopy, infraredspectrum, X-ray diffraction analysis, etc, with regard to the complex structure and explosivescrystallization, the influence of the supercritical fluid booster rate, temperature, pressure,pressure maintaining, aeration and surfactant addition PVP were analyzed, and then theprepared products were characterized, including testing performance such as the impact,friction, thermal decomposition, etc, and finally the nano-composite explosives containingboron and aluminized are compared respectively.The results shows that 90% RDX was dissolved into the precursor solution, which was0.2 mol/L FeCl₃·6 H₂O in the DMF solution, and then the catalyst epoxy propane with aproportion [Fe] : [C₃H₆O] = 1:15 and 2% PVP were added into the solution, after that it was24 hours for gel aging, and finally the wet gel crystallized by supercritical fluid dryingtechnology, whose temperature and pressure was 40℃and 10MPa, boost rate was15L/h, airexchange rate was2L/h, air exchange time was 1 h, gas release rate was 1² bar/5 s, thusobtaining the completely composite energetic materials with uniform structure and withoutany explosives crystal separation, whose particles were spherical and particle sizes were from30 nm to 50 nm with narrow distribution and mechanical sensitivity got reduced. With 2%sub-micron B powder added into the solution, the characteristic falling height of the impactsensitivity of RDX/Fe2O3/B was 40.08 cm, which was 109.8% higher than the raw material,and the explosion probability of its friction sensitivity was 28% lower than the raw materials 100%; And in comparison with addition of the nano Al powder, the sub-micron B had a moreeffective function on the reduction of the impact sensitivity of the nano-composite energeticmaterials, and had a less effective function on the reduction of the friction sensitivity than thenano Al powder. The DSC of the nano-composite energetic material shows that the thermaldecomposition rate of nano-composite explosives was more quickly and completely, and themass enthalpy released by the composite explosives with sub-micron B addied into was1764.282J/g, which was obviously higher than the mass enthalpy released by the compositeexplosives without sub-micron B, so the above results showed that the addition of sub-micronB effectively improve the heat release, and also improve the thermal decompositioncharacteristics of the composite explosives, so as to achieve the periodical objectives.Finally the heat value of detonation of the B explosives was caculated theoretically, andit can be concluded that nano-composite energetic materials with the quantitative sub-micronB could be expected to become the new explosives with high energy output.