Study On Micro/nano Structured Energetic Composites Prepared By Inkjet Printing And Their Basic Applications

Inkjet printing has been enjoying constant researches in the field of micro electro mechanical system?MEMS?fuze safe&arming?S&A?devices regarding explosive train charging for its superb precision,flexibility and automation.This dissertation focused on the particle-freeexplosiveinksbasedonpentaerythritetetranitrate?PETN?,hexanitrohexaazaisowurtzitane?CL-20?and 3,4-dinitrofurazanofuroxan?DNTF?.Moreover,the energetic composites were prepared through inkjet printing device and their detonation properties at micro scale charge were mainly analyzed and discussed.The research results can promote the application of inkjet printing technology in the field of micro scale charge at a certain degree.First,particle-free explosive inks were prepared with PETN as the main explosive,ethyl cellulose?EC?,Viton and glycidyl azide polymer?GAP?as the binder and acetone the co-solvent.Then,four energetic composites including PETN/EC,PETN/EC/Viton,PETN/Viton and PETN/EC/GAP were obtained through inkjet printing.Moreover,the prepared energetic composites received a series of tests and characterizations involving printed density,the monolayer thickness,microstructure,crystal type,thermal stability,mechanical properties,adhesion strength through electronic densimeter,digital microscope,scanning electron microscope?SEM?,X-ray spectroscopy?EDS?,X-ray diffraction?XRD?,nano identer and bonding strength tester,respectively.Last but not the least,the impact sensitivity and detonation properties at micro scale charge of the four composites were tested and analyzed.Results indicate that for PETN/EC,PETN/EC/Viton,PETN/Viton and PETN/EC/GAP,the printed density reach 86.09%,73.92%,78.74%and 79.88%of their TMD values,respectively.Compared with raw PETN,the four composites display better thermal stability and lower impact sensitivity.The critical sizes of detonation of PETN/EC,PETN/EC/Viton,PETN/Viton and PETN/EC/GAP composites are 1 mm×0.108 mm,1 mm×0.101 mm,1 mm×0.140 mm and 1 mm×0.011 mm,respectively,exhibiting excellent detonation properties at the micro scale charge.According to the experiment results and analysis,the PETN/EC/Viton composite and PETN/EC/GAP composite both have the capacity to ignite the PBXN-5 grain for their detonation velocity reaching 6204 and 7110m·s^-1 at the charging dimension of 1 mm×1 mm,which shows that the addition of GAP has a substantial influence on the improvement of detonation properties under the micro scale charge.Second,two kinds of particle-free explosive inks were prepared with CL-20 as the main explosive,nitrocotten?NC?/EC and GAP as the binder and ethyl acetate the co-solvent.Then,CL-20/NC/GAP and CL-20/EC/GAP composites were obtained through inkjet printing.Furthermore,the composites received a series of tests and characterizations involving printed density,the monolayer thickness,microstructure,crystal form,thermal stability,adhesion strength through electronic densimeter,digital microscope,SEM,XRD,DSC,and bonding strength tester,respectively.The impact sensitivity and detonation properties of the two composites were also tested and analyzed.Results show that the explosive particles of the both explosives are roughly in the shape of spheroid.The particle size of CL-20/NC/GAP composites is less than 1?m while the size of CL-20/EC/GAP composites is around 1?m.Both particles are closely attached to the binder matrix.The printed density of CL-20/NC/GAP and CL-20/EC/GAP composites lies in 86%and 85.5%,reaching 1.70 g·cm^-3and 1.66 g·cm^-3.The particle size of CL-20/NC/GAP composites is less than 1?m while the size of CL-20/EC/GAP composites is around 1?m.Concerning impact sensitivity,the two composites have a better performance than that of raw CL-20.According to the explosive test,CL-20/NC/GAP and CL-20/EC/GAP composites have displayed superb detonation capacity with whose critical size of detonation 1 mm×0.0096 mm and 1 mm×0.069 mm,respectively.According to the experiment results,the CL-20/NC/GAP composite and CL-20/EC/GAP composite both have the capacity to ignite the PBXN-5 grain for their detonation velocity reaching 8347 m·s^-1 and 8013 m·s^-1 at the charging dimension of 1 mm×1 mm.The XRD pictures show the type?is the basic crystal type of CL-20 in the two composites.Further study shows the transition from?-CL-20 to?-CL-20 can not be achieved by adjusting binders and amount in the formulations of CL-20 based explosive inks.It also indicates that reducing the co-solvent evaporation is one of the effective solutions to control the transition of CL-20.Finally,the particle-free explosive inks were prepared with DNTF as the main explosive,NC,EC,Viton and GAP as the binder and acetone the co-solvent.Then,DNTF/NC/Viton composite and DNTF/cyclotrimethylene trinitramine?RDX?based composites were obtained through inkjet printing.Moreover,the DNTF/NC/Viton composite received a series of tests and characterizations involving printed density,the monolayer thickness,microstructure,crystal form,thermal stability,adhesion strength through electronic densimeter,digital microscope,SEM,PDSC,XRD,and bonding strength tester,respectively.The impact sensitivity and detonation properties of the two composites were also tested and analyzed.The industrial CT?digital microscope,SEM,PDSC and XRD were utilized to test the properties of DNTF/RDX based composites.Results show that the printed density of DNTF/NC/Viton composite is 1.785 g·cm^-3,reaching 93.16%of TMD.The particles in DNTF/NC/Viton composite are spheroidal with size ranging from 1 to 2?m.Compared with raw DNTF,the prepared composite has a lower impact sensitivity and higher thermal stability.Moreover,DNTF/NC/Viton composite exhibits excellent detonation properties,whose critical size of detonation is 1 mm×0.0081 mm,and the detonation velocity is 8580 m·s^-1 at the charging size of 1 mm×1 mm.The study of DNTF/RDX based composites illustrate that the prepared composites have good uniformity in structure.In addition,the DNTF/RDX based composites have high printed density with all values higher than 90%TMD.DNTF/RDX based composites also display a good capability in steadily detonating above the size of 1 mm×0.32 mm.Further study shows that the low-melting-point of DNTF is the key factor in obtaining high printing density during inkjet printing.