Study On Improving The Performance Of Nitroguanidine Propellant By Process Improvement At Low Temperature

To improve the mechanical properties and the combustion stability of nitroguanidine(NQ)propellants at low temperature environment,the reason of poor mechanical properties of nitroguanidine propellants were analyzed,and process conditions of nitroguanidine propellants were studied.Propellants had been prepared in different NQ contents(10%,20%,30%,40%,47%and60%),solvent proportion of alcohol/ketone(2:3,1:land3:2),post-plasticization treatment time(1,3,5and7days).Mechanical and combustion properties of propellants were tested respectively by the Impact Testing Machine,Universal Testing Machine and Closed Bomb Vessel Test.The results show that:In the six different NQ contents propellants,with the NQ content of propellants increasing,the mechanical performance of the propellant were first increased and then decreased,burning rate and the maximum burning pressure of the propellant were decreased.When the content of NQ is 30%,the comprehensive performance of propellants is the best;when the ratio of alcohol/ketone was 1:1,the NQ propellant had optimal comprehensive performance;by prolong post-plasticizing time,mechanical performance and relative gradient(RQ)of propellants were first increased and then decreased.The combustion of the propellant is more stable at low temperature.And the optimal time of post-plasticization treatment is 5 days.Based on the above research,NQ was surface-treated by three kinds of bonding agents(Acrylamide(AM),Triethanolamine(TEOA)and KH550),and the corresponding modified nitroguanidine propellant was prepared,mechanical properties and the combustion properties were studied.It was found that,KH550 and TEOA had the best surface treatment of NQ.The mechanical properties of propellant modified by KH550 and TEOA were improved,and burning rate and RQ of propellants modified by KH550 was reduced,and the probability of occurrence at a low temperature abnormal combustion is lowered.The results showed that nitoguanidine propellants modified by KH550 has the best performance.