The Design And Study Of Inhibition With The Excellent Performance Of Bonding And Resisting Nitroglycerin Migration Used For Double-base Propellant

The failure of inhibition is the major problem that shortens the storage age of the double-base propellant, which is due to the poor performance of bonding and resisting nitroglycerin migration. In order to improve the performance, barrier coats were designed in inhibition of double-base propellant by polyurethane and silicone rubber. The performance of bonding, resisting migration and compatibility with propellant were also investigated.Due to the excellent bonding performance and mechanical properties, polyurethane is used as the inhibitor of double-base propellant. However, the performance of resisting nitroglycerin migration of polyurethane is poor. First, TG-DSC-QMS was used to investigate the nitroglycerin migration and the pact on thermal stability of polyurethane. Second, three barrier coats were designed to improve the performance of resisting migration. The barrier coat consisting of phenolic resin, polyvinylbutyral and 3-aminopropyltriethoxysilane shows the best performance of resisting migration, which reduces the migration from 4.6% to 0.5% after migrating at 65℃ for 144 h. The compatibility with propellant is grade I according to GJB 5383.11-2005.Due to the good performance of resisting migration, thermal stability and resisting erosion, silicone rubber is a new inhibitor. However, the bonding performance and mechanical property of silicone rubber are unsatisfying. First, nitroglycerin migration was investigated. The result shows that after migrating for 120 h at 65℃, only 1.1% nitroglycerin migrated. Second, the barrier coat consisting of phenolic resin, polyvinylbutyral and 3-aminopropyltriethoxysilane was used to improve the bonding performance with propellant. The result shows that silicone rubber inhibitor without barrier coat detached partly after aging 96 h at 65℃, and had a complete detachment after 288 h. For inhibitor added barrier coat, no detachment was observed after 288 h.Through contrast experiment, the propellant inhibited by silicone rubber with barrier coat demonstrates the excellent performance in resisting the nitroglycerin migration, thermal stability and bonding performance. The combustion performance of rocket engines with the above propellant was studied. The results show that the engines work well at room temperature (25℃), low temperature (-50 ℃×12 h), high temperature (60℃×12 h) and after alternating high and low temperature experiments, which indicates that no detachment occurs. That proved the design of inhibition is practicability and feasibility.