Multiscale design, interaction mechanism and performance of CL-20/Al energetic composites with embedded structure

In order to design and prepare hexanitrohexaazaisowurtzitane/aluminum (CL-20/Al) composites, the contact state of CL-20 with aluminum particles under different mixed solvent contents were calculated with the method of dissipative particle dynamics (DPD). Then the modified attachment energy (AE) model was applied to predict the morphologies of CL-20 in ethyl acetate, hexane and ethyl acetate/hexane mixed solvents. Furthermore, the morphologies, the surface element distribution, the sensitivity and the energy performance of CL-20/Al composites prepared with the solvent/non-solvent method were characterized, and the interaction mechanism were also obtained. The results achieved show that phase separation phenomenon becomes obvious with the decrease of ethyl acetate/n-hexane mixed solvent content. CL-20/aluminum particles will form the composites of aluminum particles embedded in CL-20 crystal when the solvent content is zero. The order of modified attachment energies for ethyl acetate/hexane mixed solvents on CL-20 faces is (011) > (110) > (101) ≈ (11-1) ≈ (10-1) > (002). Besides that, the crystalline morphology of CL-20 in acetate/hexane mixed solvents is spindle-shaped. There are many Al particles embedded in CL-20 crystals of CL-20/Al composites prepared by using solvent/non-solvent method. The calculated results agree well with the experimental results. In CL-20/Al composites, aluminum particles interact with CL-20 mainly through hydrogen bond and strong van der Waals force. The sensitivity of CL-20/Al composites decreased obviously compared with pure CL-20 and mechanical mixing composites. Besides, the CL-20/Al composites with embedded structure can increase the explosion reaction temperature to 791.2 K, which has obvious energy advantage compared with CL-20/Al physical mixture.