Thermal decomposition mechanism of particulate core-shell KCLO₃-HMX composite energetic material

The thermal decomposition mechanism of a newly designed composite material KClO₃-HMX (KC-HMX) is investigated by combined TG-DSC-FTIR technique and T/Jump in-situ thermolysis cell/FTIR (T/Jump FTIR) technique. It is shown that KC-HMX began to decompose at about 266°C without melting, and the fast stage of mass loss at the temperature range of 268.4~290.1°C is considered to be the result of the thermolysis and complex reactions of KClO₃ and HMX with energy release of 1859 J.g^-1, which exceeded that of pure HMX about 40%. It is also shown that CO, CO₂, NO₂ and H₂O were the main gaseous products. The T/Jump FTIR analysis showed that the competing reactions of N-N and C-N bonds cleavage occurred in initial stage of HMX decomposition are greatly affected by KClO₃. In contrast of pure HMX, there is no CH₂O and HCN detected in its thermolysis products. In presence of electronegative oxygen radical produced by thermolysis of KClO₃ oxidized CH₂O and HCN through gas-phase reaction "(NO₂+4O₂) + (2N₂O+5CH₂O) → 5NO+3CO+2CO₂+5H₂O", which is probably the dominating reaction, being immediately followed by the decomposition reaction of HMX.