Preparation And Properties Of Micro-Spherical Energetic Nanocomposites Prepared By Spray Drying

The paper takes the miscible explosive-binder solution as the spray drying precursor. Thespray drying technological parameters of HMX-based and RDX-based micro-sphericalenergetic nano-composites were optimized. HMX-based, RDX-based, CL-20-based andCL-20/RDX micro-spherical energetic nano-composites were prepared by spray dryingtechnology. The properties of them were tested and characterized.Firstly, the technique parameters which can obtain the optimum particle morphologywere confirmed using SEM. The optimum parameters of the spray drying process whichprepared RDX-based micro-spherical energetic nano-composites are: inlet temperature:85℃;flow rate of air:660L/h; flow rate of feed solution:1.5ml/min. The optimum parameters ofthe spray drying process which prepared HMX-based micro-spherical energeticnano-composites are: inlet temperature:55℃; flow rate of feed solution:4.5ml/min; flowrate of air:430L/h.Secondly, different HMX-based micro-spherical energetic nano-composites wereprepared using F2602、Estane5703and NC as a binder, respectively (HMX-binder ratio were98:2, the three samples were marked as HMX/F2602，HMX/Estane5703，HMX/NC,respectively). Micro-spherical HMX which contains no binder (HMX-1) was prepared byspray drying technology and the solution took raw HMX as the solute. The products weretested by SEM (Scanning Electron Microscope), DSC (Differential Scanning Calorimetry),XRD (X-Ray Powder Diffraction) and XPS (X-ray Photoelectron Spectroscopy). The impactsensitivity was also tested. The results show that all products are spherical nano-composites.The size of tiny particles is30nm~100nm. HMX based micro-spherical energetic nano-composites which contain different binders have different morphology. Compared withthe raw HMX, the activation energy and thermal sensitivity of HMX-1are all decreased. Theactivation energies of the three HMX based micro-spherical energetic nano-composites areincreased. The thermal sensitivity of HMX/F2602is the lowest. The crystal form of all samplesis unchanged. The impact sensitivity of HMX-1decreases greatly. NC has no effect on impactsensitivity of samples. The sample which has most obvious impact sensitivity downward trendis HMX/F2602. The blending mode of HMX and F2602is surface coating. The blending mode ofHMX and Estane5703, HMX and NC is internal even mixing.Thirdly, different RDX-based micro-spherical energetic nano-composites were preparedusing F2602、Estane5703and NC as a binder, respectively (RDX-binder ratio were95:5, thethree samples were marked as RDX/F2602，RDX/Estane5703，RDX/NC, respectively).Micro-spherical RDX which contains no binder (RDX-1) was prepared by spray dryingtechnology and the solution took raw RDX as the solute. The products were tested by SEM,DSC, XRD and XPS. The impact sensitivity was also tested. The results show that allproducts are spherical nano-composites. Compared with the raw RDX, the activation energyof RDX-1changes little and the thermal sensitivity of it rises. The activation energy of RDXbased micro-spherical energetic nano-composites are all decreased. The thermal sensitivity ofRDX/F2602is the lowest. Product which has the highest equal dynamical point is RDX/NC.The crystal form of RDX-1and RDX based micro-spherical energetic nano-composites isunchanged. The blending mode of all RDX based micro-spherical energetic nano-compositesis surface coating. The impact sensitivity of RDX-1decreases greatly. All the three binderscan decrease the impact sensitivity of samples further.Finally, the F2602and-CL-20was taken as the binder and main explosive, respectively.The different CL-20/F2602(CL-20:F2602=97:3) micro-spherical energetic nano-compositeswere prepared by spray drying using different solvent and inlet temperature. The misciblesolution contained CL-20and RDX (mole ratio1:1) was taken as the precursor solution ofspray drying and the co-crystallizing product CL-20/RDX was obtained. The products weretested by XRD, SEM and DSC. The results show that the crystal type of all CL-20/F2602 micro-spherical energetic nano-composites is β type, which were prepared by spray dryingusing different solvent and inlet temperature. All products prepared using different solvent arespherical nano-composites but the surface morphology of them are different. The particlemorphology of CL-20/RDX was roundish and the particle size of it is2~5μm. It can bespeculated that the CL-20/RDX sample is a type of co-crystallizing. Compared with the rawCL-20, the activation energy of CL-20/F2602is increased and the thermal sensitivity of itchanges little. The impact sensitivity of CL-20/F2602decreases greatly.