Research On Reduced Sensitivity Of CL-20 With Surface Coating

Hexanitrohexaazaisowurtzitane(CL-20)is currently one of the most promising explosives with high detonation velocity and detonation heat,stable thermal performance.CL-20 is so sensitive to mechanical force,which hinder its development in practical application.In recent years,the scholars carried out a series of studies about reducing the mechanical sensitivity of CL-20 achieved remarkable success.However,there are rare reports about coating CL-20 with complex formulas composed by desensitizer and polymer binder to reduce the mechanical sensitivity of CL-20.This dissertation is dedicated to the reduction of sensitivity of high energetic density explosives-CL-20.Two complex formulas were named ERH and FRH.ERH was composed by microcrystalline wax and polyurethane Estane5703,FRH was composed by microcrystalline wax and fluororubber F2311.Using water suspension coating method,CL-20 was manufactured to polymer bonded explosives(PBX)coated by ERH and FRH.All of PBX were characterized by X-ray diffractometer(XRD),scanning electron microscope(SEM),differential scanning calorimeter(DSC),their mechanical sensitivity were tested.Then studied four technological parameters including experimental temperature,feed rate,stirring speed,vacuum,how to influence the appearance and mechanical sensitivity of PBX.Furthermore,the theory of PBX's mechanical sensitivity was influenced by the coating order of desensitizer and polymer was proved.And experiment measured the minimum amount of coating agent.Experiments show that: taking water suspension method,CL-20 was coated by ERH perfectly when four technological parameters were appropriate.PBX prepared by ERH was like uniform size ellipsoid,and the crystal of CL-20 was not changed.If there were 2% microcrystalline wax coating internally and 2% Estane coating externally,the impact sensitivity of CL-20 decrease from 100% to 40% and the friction sensitivity of CL-20 decrease from 100% to 48%.Taking water suspension method,CL-20 was coated by FRH perfectly when four technological parameters were appropriate.PBX prepared by FRH was like uniform size ellipsoid,and the crystal of CL-20 was not changed.If there were 2% microcrystalline wax coating internally and 2% F2311 coating externally,the impact sensitivity of CL-20 decrease from 100% to 60% and the friction sensitivity of CL-20 decrease from 100% to 68%.