Preparation And Characterization Of Ultrafine High Quality RDX Based PBX

Cyclotrimethylene trinitrate(RDX)is the most widely used high-energy explosive with high energy,high density,stable performance and low cost.However,due to its high sensitivity and poor safety,so it is necessary to carry out the desensitization treatment.In this paper,RDX was refined and RDX-based high polymer bonded explosive(PBX)was prepared to reduce the sensitivity of RDX.The main research contents are as follows:(1)The materials studio software was used to simulate the equilibrium system bet ween RDX and five polymer binders(AR-12,AR-14,AR-71,Viton A and F2602),an d calculate the binding energies between them.The result is RDX/AR-12>RDX/AR-14>RDX/AR-71>RDX/Viton A>RDX/F2602.The stability of the system is judged by the combination of the size of the energy,which provides a theoretical basis for the form ulation design of RDX/ACM.(2)submicro RDX was prepared by spray drying refining method.The effects of drying temperature,spray rate and RDX concentration in solution on the particle size and morphology of the prepared RDX crystals were studied during the experiment.Studies have shown that when the drying temperature is 90?,the spray rate is 1 ml/min and the RDX solution mass concentration is 4%,the prepared ultrafine RDX particles are spherical and the particle size distribution is narrow,at 400-600 nm.The submicro RDX which was prepared under the optimum process conditions was tested and characterized by scanning electron microscopy(SEM),X-ray powder diffractometry(XRD)and differential scanning calorimetry(DSC).The results show that the prepared ultrafine RDX crystal type was not changed,the apparent activation energy was reduced by 24.52 KJ/mol compared with raw RDX,and the thermal stability was slightly reduced;meanwhile,the impact sensitivity characteristic height was increased by 35.3 cm,and the friction sensitivity was lowered.At 35%,the mechanical sensitivity was greatly reduced and the safety was significantly improved.(3)Dimethyl sulfoxide was used as solvent and deionized water as non-solvent,the micron-sized RDX was prepared by ultrasonic spray refining method,and the samples were tested and characterized.The results show that the micron-sized RDX particle size distribution is 2-5?m,the particles are ellipsoidal and the surface is smooth without obvious sharp edges.Compared with raw RDX,the apparent activation energy of micron-sized RDX was reduced by 10.5KJ/mol,the thermal stability was slightly reduced,and the impact sensitivity was increased by 16.8cm,and the safety was improved.(4)Six PBX explosives with different formulations were prepared by solution water suspension method with the micron-sized RDX as a base explosive.The particle size,morphology,thermal decomposition properties,mechanical sensitivity and static mechanical properties of the samples were tested and the explosive performances of the samples were calculated.The results show that the RDX-based PBX prepared by the water suspension method has a particle size of 100-300 ?m,and the crystal structure has not changed.The thermal stability and safety have been improved.In the case of the same binder,the thermal stability and safety were improved when the binder content was higher,but the explosion performance would be worse.Among them,the apparent activation energy of RDX/AR-71(97/3)increased by 11.6KJ/mol,the impact sensitivity characteristic height increased by 21.1cm,the friction sensitivity decreased by 27%,and the compressive strength increased by 127%.It has the best combination performance,indicating that it can be used as a new formula with good performance and high safety.