Abstract: Thermal behavior under pressures of 0.1, 4, and 7MPa and non-isothermal decomposition reaction kinetics under pressures of 4 and 7MPa of the composite modified double base propellant containing hexanitrohexaazaisowurtzitane (CL-20-CMDB propellant) were investigated by differential scanning calarimetry (DSC) and thermogravimetry (TG). The results showed that there were three exothermic peaks on DSC curve and three mass loss stages on TG curve under 0.1 MPa. There was only one exothermic peak on the DSC curve under 4 and 7 MPa. The exothermic peak temperatures under 4 and 7 MPa increased with increasing the heating rate. The exothermic decomposition reaction mechanism and kinetic parameters of the propellant changed little with testing surroundings. The reaction mechanism was randomnucleation and then growth. The kinetic equations of exothermical decomposition reaction can be expressed as, dα/dt=1014.5(1-α)[-ln(1-α)]1/3e-17981.7/T (under 4 MPa) and dα/dt=1014.7(1-α)[-ln(1-α)]1/3e-18138.1/T (under 7 MPa).

Key words: Propellant, Thermogravimetric analysis, Differential scanning calarimetry, Non-isothermal reaction kinetics, CL-20