Preparation And Performance Study Of CL-20 Filled 3D Graphene Composite Structures

Hexanitrohexaazoisowoodsane（CL-20）is a typical representative of today’s high energy density materials.Due to its high energy density,high burst velocity,high burst pressure and other excellent explosive properties,CL-20 has been widely favored by the fire explosives industry.However,its higher mechanical sensitivity and poor safety performance make the application of CL-20 very limited.Therefore,how to improve the comprehensive performance of CL-20 is an important research topic.In recent years,further design and research into graphene-based materials has enabled them to demonstrate a range of unprecedented properties.As a result,graphene-based materials are often used as additives in CL-20modifications.The thesis uses a variety of methods to prepare three-dimensional graphene aerogel materials with a layered domain-limited spatial structure,and introduces CL-20 into the material framework.The problem of how to uniformly disperse graphene-based materials in CL-20 was solved,and new ways to improve the comprehensive performance of CL-20 were explored.The main research contents and results are as follows.（1）A variety of graphene aerogels（GA）with unidirectional orientation structure were prepared by the ice template method using graphene oxide（GO）as raw material.The microscopic morphology,elemental distribution and functional group composition of various GA（GA1,GA2,GA3）structures were analysed using a variety of characterisation methods.The results show that among the various graphene aerogels prepared,GA1 has a more regular and stable structure.Scanning electron microscopy（SEM）tests show that GA1is internally in a regular pipe format and has high mechanical strength overall;X-ray diffraction（XRD）tests showed that GO was effectively reduced during the preparation of GA;Raman spectroscopy（Raman）tests showed that the degree of defects in the prepared GA became higher,with GA1 being less defective than GA2 and 3;X-ray photoelectron spectroscopy（XPS）tests showed the highest degree of reduction in GA1.The ice template method can regulate the orientation structure of GA and improve the agglomeration problem of graphene.（2）Based on the ice template method,the framework structure was redesigned and a three-dimensional graphene composite structure（PGA）was prepared using a bidirectional freezing method.The CL-20/PGA composite structure was obtained by filling CL-20 into the PGA framework structure through a template adsorption solvent method.The microscopic morphology,compositional structure,elemental distribution and functional group composition of PGA and CL-20/PGA composite structures were characterised and analysed,their thermal decomposition properties and susceptibility characteristics were tested,and the burst parameters of the composite structures were calculated.The results show that the thermal decomposition performance of the CL-20/PGA composite structure is improved compared to that of the raw material CL-20,the peak temperature is reduced by 6°C and the E_ais reduced by 35.3k J/mol.The characteristic drop height H₅₀has been reduced by 10.3cm compared to the CL-20 and the frictional sensitivity has been reduced by 125%.The blast velocity of the composite structure was calculated to be reduced by 315m/s and the blast pressure by 2.33 GPa.（3）Three-dimensional graphene structures（CGA）were prepared from graphene oxide（GO）and fullerene（C60）using a bi-directional freezing method.The CL-20/CGA composite structure was obtained by filling CL-20 into the CGA framework structure via a template adsorption solvent method.The microscopic morphology,compositional structure,elemental distribution and functional group composition of CGA and CL-20/CGA composite structures were characterised and analysed,their thermal decomposition properties and susceptibility characteristics were tested,and the burst parameters of the composite structures were calculated.The results show that the thermal decomposition performance of the CL-20/CGA composite structure is improved compared to that of the raw material CL-20,the peak temperature is reduced by 3.7°C and the E_ais reduced by 55.1 k J/mol.The characteristic drop height H₅₀has been reduced by 15.3cm compared to the CL-20 and the frictional sensitivity has been reduced by 162.5%.The blast velocity of the composite structure was calculated to be reduced by 227m/s and the blast pressure by 1.3 GPa.