Construction And Performance Study Of CL-20-Based Composites

CL-20 has the advantages of high energy,high burst velocity,high burst pressure and high burst heat,and is the highest energy single-matter explosive that can be used in practice.In this project,to address the problem of high mechanical and electrostatic susceptibility of CL-20,based on the super adhesion of polydopamine(PDA),an in-situ self-polymerisation method was used to construct a PDA shell layer on the surface of CL-20 to prepare CL-20@PDA composites;in addition,based on the large number of active groups such as hydroxyl and amino groups on the surface of PDA,it was used as a secondary modification platform to prepare CL-20@PDA@r GO composites with CL-20 as the core and PDA and GO as the cladding layer by self-assembling GO onto the CL-20@PDA surface,and the preliminary exploration of CL-20@PDA@r GO composites in composite solid propellants applications.Details of the study are as follows:(1)CL-20@PDA composites were prepared by in situ polymerisation using PDA-coated CL-20 crystals.To investigate the effects of polymerisation time,dopamine(DA)monomer concentration and H₂O₂ addition on the morphology,structure and properties of CL-20@PDA composites,a three-factor,five-level orthogonal experiment was designed,and a high value of the impact susceptibility property(H₅₀)was selected as the basis for the comprehensive evaluation of the preparation of CL-20@PDA composites.The results showed that the PDA was successfully coated on the surface of CL-20 and the preparation conditions did not affect the crystalline shape of CL-20,the influence of various factors on the properties of CL-20@PDA composites was in the following order:DA monomer concentration>H₂O₂ In addition,the best preparation conditions for CL-20@PDA composites were found to be 24 h polymerization time,2 mg/m L DA monomer concentration and 1%H₂O₂ addition,and the impact sensitivity of CL-20@PDA composites prepared under these optimal conditions was lower than that of the raw CL-20.The impact susceptibility was reduced by 221.6%compared to the raw material CL-20,the transcrystallization temperature was extended by 24.1?,the peak thermal decomposition temperature was increased by 9.0?,and the safety and thermal stability were significantly improved.(2)The CL-20@PDA@r GO composites were prepared by self-assembly method based on the active groups such as hydroxyl and amino groups on the surface of PDA,and the CL-20@PDA@r GO nanosheets were coated on the surface of CL-20@PDA prepared under the optimal experimental conditions,and the effects of reaction time and GO addition on the morphology,structure and properties of the composites were investigated.The results showed that GO was successfully coated on the surface of CL-20@PDA,and the preparation conditions did not affect the crystalline shape of CL-20;the reduction effect of CL-20@PDA@r GO composite showed a trend of increasing and then decreasing with the increase of reaction time and GO addition.278.4%,and the electrostatic accumulation decreased from 4.32 n C/g to 0.127n C/g compared with the raw material,a reduction of 97.06%;In addition,the thermal decomposition peak temperature is further increased by 5.8?on the basis of CL-20@PDA,which was 14.8?higher than that of the raw CL-20,the transcrystallization peak disappeared during heating and no transcrystallization occurred,and the safety was further increased.(3)Finally,the prepared blunt CL-20@PDA@r GO composite was applied to the HTPB composite solid propellant,and the thermal and combustion properties of the CL-20@PDA@r GO-based/HTPB composite solid propellant were initially investigated.The results show that the CL-20@PDA@r GO composite solid propellant has similar thermal decomposition characteristics as the raw CL-20,and the burning rate is slightly reduced,but the burning rate pressure index in each pressure section all less than 1,which means that the CL-20@PDA@r GO composite solid propellant is less sensitive to pressure and the burning rate of the propellant is less dependent on the pressure.