Sensitivity evolution of NEPE propellant during ageing

摘要

With high level of output energy, NEPE (Nitrate Ester Plasticized Polyether) propellant has attracted considerable attention. However, it also suffers from ageing problems due to the decomposition of the nitrate ester plasticizer and production of NO_2. which results in further decomposition of polymer substrate. Besides aroused mechanical problems, this process can also lead to a safety problem. To investigate the sensitivity evolution of NEPE propellant during storage life, variations of 5-second explosion temperature, volume of released gas in vacuum stable test, characteristic drop height, 50% explosion pressure and static spark energy with accelerated ageing time were monitored and the results were treated with fuzzy comprehensive evaluation (FCE) method. A tendency of increasing sensitivity was noticed. The results show that after approximately 36-45 days' ageing under 70 °C, the sensitivity went through a step change. The pores created by the integrity compromise of polymer structure during ageing accounts for the sensitivity evolution of NEPE propellant. As such, the discovery of more effective stabilizer is urged to improve the storage safety of NEPE propellant.