Study On The Effects Of Pressures On The Thermal Decomposition Kinetics Of Different Solid Content Propellant

The thermal decomposition reaction mechanism and kinetics of the double-base propellant,nitroguanidine propellant(NQ content are 47%,30%and 10%)and RDX propellant(RDX content are 40%,30%and 10%)were investigated by high-pressure differential scanning calorimetry(PDSC).The environmental pressures were 0.1,2 and 4 MPa.The isoconversional nethods used to calculate the kinetic triplets and the thermodynamic property date.The results of PDSC show that,the double-base propellant and different NQ content nitroguanidine propellant show only one exothermic peak under 0.1 MPa,but it shifts to two exothermic peaks under high pressures with 10%-NQ content.With the increase of RDX contents,the second exothermic peak was more obvious.The high pressures lower the peak temperature of different solid propellants under 0.1 MPa,but raise the decomposition heat.The results calculated by isoconversional method show that,application of elevated pressures changes the mechanism of thermal decomposition of the propellants compared to that under 0.1 MPa.The NQ content also change the mechanism functions,when the propellant containing 47%-NQ,the mechanism functions were the same as the DB propellant.The 30%-NQ based propellant show different reaction mechanism with the DB propellant under 0.1 MPa,the same under high pressures.The thermodynamic parameters indicate that,with the increase of pressures,the critical temperature(Tbe)of thermal explosion of the propellants decrease,which lead to worse thermal stability under high pressures.For the three kinds of nitroguanidine propellant.47%-NQ propellant has a better thermal stability;for the three kinds of RDX propellant,40%-RDX propellant hold more optimal thermal stability.