Study On The Combustion Performances Of High-energy And High-strength Gun Propellant

Two kinds of high-energy and high-strength propellants including JMZ gun propellant and TPUE modified high-energy gun propellant were studied. The mesh system of JMZ gun propellant was established with nitrate ester plastized poly(ether,urethane); Thermoplastic polyurethane elastomer was used as reinforce additive of TPUE modified high-energy gun propellant. From the theoretical and experimental aspects two kinds of gun propellants were studied.The energetic characteristics of gun propellants were calculated in theory and researched by experiment. Some base formulations were designed. By the methods of extrusion, the high-energy and high-strength tubular propellants were prepared in different technical conditions. The combustion performances of gun propellants and some factors that affect combustion performances were studied by closed bomb test.The results showed that JMZ gun propellant with the main network system of poly(ether,urethane) has a high energy level, while mechanical properties improved. The combustion rate of JMZ gun propellant is low. This type of gun propellant has the properties of low burning rate and high burning rate pressure exponent value. The combustion performance of gun propellants will be affected by chain extender, technical conditions, crosslinking system and propellant components.TPUE modified high-energy gun propellant has a high-energy nature for containing RDX. The burning rate pressure exponent value is about 1.0 and it have well combustion stability. Nitroguanidine propellant without RDX has a lower energy level and smaller burning rate pressure exponent value which is under 0.8. The combustion performance of high-energy gun propellant will be affected by the amount of TPUE additive. With the percentage of TPUE increases, the powder force decreases, the covolume increases and the total burning rate slows down. The energy properties and combustion performance can be adjusted through changing components. Compared to JMZ gun propellant, TPUE modified high-energy gun propellant has higher combustion temperature and lower propellant specific volume.