The Study On Preparation And Properties Of Gun Propellant With CL-20

To improve the energy performance of propellants,studies on high-energy propellants with CL-20 was carried out,in which CL-20 and RDX were used as high-energy solid additives.They have high energy and density.In the study,thermoplastic elastomer partially replaced nitrocellulose as binder matrix of propellants,which can make the propellants have high energy and relatively high mechanical properties.The specific preparation process of propellant was determined by the dissolution test of thermoplastic elastomer,kneading and pressing of medicines.A series of propellants with CL-20 were prepared by the process.The mechanical properties,safety and stability of propellant with CL-20 were studied by compression test,impact test,impact sensitivity test,5S burst point delay test,vacuum stability test and DSC test.A preliminary study on the pretreatment method of propellant mechanical properties simulation was carried out,in which program for calculating the center coordinates of random distribution of solid additive spheres based on MATLAB is compiled.According to the dissolution test of thermoplastic elastomer,equal volume of tetrahydrofuran,ethanol and acetone was used to prepare the mixed solvent,and the amount of mixed solvent was determined according to the ratio of solvent to binder,that is the ratio of solvent to solvent 3:1.Before kneading,the mixed solvent is used to dissolve thermoplastic elastomer under the condition of heating and stirring.After the completion of dissolving,the thermoplastic elastomer solution with other medicine were to join the kneading machine with constant temperature kneading of 60?,and the kneading time is 3 hours.Finally,the finished product of the propellant sample is obtained through processes such as extrusion,dissolving,granulating and drying.The mechanical tests show that the nitrogen concentration of nitrocellulose has a significant effect on the elastic modulus of the propellant.The propellant with higher nitrogen concentration of the nitrocellulose shows higher elastic modulus.The propellant prepared by inert thermoplastic elastomer without side group has better compressive strength and impact strength than that prepared by ETPE with side group.The propellant has relatively good impact strength when higher number average molecular weight energetic thermoplastic elastomer?Mn=31000 g/mol?is used.The impact sensitivity and thermal sensitivity tests showed that the impact sensitivity of solid additives could be significantly reduced by the dispersion of the thermoplastic elastomer in the propellant and the nitrocellulose blend binder in the solid energy additive,and the passivation effect of the inert thermoplastic elastomer was better than that of the energy-containing thermoplastic elastomer.The 5s temperature of thepropellants with CL-20are all lower than CL-20.The stability of the propellant was studied by vacuum stability test and DSC test.DSC test showed that the decomposition process of propellant presented two exothermic peaks.The type of thermoplastic elastomerand the amount of average molecular have a weak influence on T_P0 and apparent activation energy of the propellant.DSC data calculated that the apparent activation energy of the three kinds of CL-20 propellants differs by less than 2kJ/mol.The difference of T_P0 is less than 0.1k,and the stability is equal.