Investigation On The New Borate Ester Bonding Agents For The High Energy Four Groups Hydroxy-Terminated Polybutadiene Propellant

The energy density of the high-energy four groups (Al/RDX/AP/HTPB) hydroxyl- terminated propellant is significantly higher than the three groups (Al/AP/HTPB) hydroxyl- terminated propellant,but the cost is significantly lower than other high-energy propellants,thus it has broad application prospect in the solid rocket.However,such kind of propellants can easily arise "dewetting" in the process of use and the mechanical properties can not meet the request.The LAB series bonding agents (modificating of alcohol amine complexing with boron trifluoride),the hydantoin and triazine series bonding agent BA603 and the borate ester bonding agent BAG-5 can effectively raise the mechanical properties of the high-energy four groups HTPB propellant when complexing with MAPO,but they can not meet the require- ments of the engine use.The purpose of this study is developing efficient bonding agents for the high-energy four groups HTPB propellant on the basis of the BAG-5 to meet the developing needs of the state's key model weapons.According to the bonding agent theory,the design of new borate ester bonding agents based on BAG-5 was proposed.A series of diethanolamine derivatives were synthesized,the main factors influencing the reactions were studied and the optimal reaction conditions were determined.Using diethanolamine and its derivatives as raw materials,a series of new borate ester bonding agents were synthesized by transesterification reaction process.The detection method of the borate ester bonding agents was established,the amine value,hydroxyl value,boron content,water content,pH,viscosity and appearance of the bonding agents were tested.The application of the new borate ester bonding agents in the 5L high-energy four groups HTPB propellant was investigated.The result showed that BA-4-1 had bonding action with both AP and RDX,its integrated performance was better than the bonding agents LAB,BA603 and BAG-5 mentioned in literatures,it was a leader in the domestic level.Uniaxial tension experiment showed BA-4-1 had improved the room temperature and high temperature mechanical performance of the propellant 15% above the design requirements of the engine;Accelerated aging experiment results showed that the propellant containing BA-4-1 had excellent ageing resistance,itsσm andεm had less change than the propellant containing BA603 during the aging,after 12 weeks accelerated aging,theεm of the propellant containing BA-4-1 was retained about 50%;Contract to BAG-5,BA-4-1 improved the processing performance of the propellant significantly.When amplifying the reaction from 5 L to 100 L,the mechanical properties of the propellant containing BA-4-1 did not loss,and test results had good repeatability,the next step can charge large engine.