Study on ammonium nitrate reactively coated by amines and their application in azido polyether propellants

For improving the hygroscopicity and surface polarity of phase-stabilized ammonium nitrate (PSAN), ethylenediamine, diethylamine and triethylamine, which represent primary amines, secondary amines and tertiary amines, were selected to react with the surface of PSAN particle to prepare amines reactively coated PSAN. The chemical reaction between amines and AN were confirmed by FTIR. The coating effects were characterized by rate of moisture absorption, contact angles and propellants tensile test. It is shown that the hygroscopicity and surface polarity of PSAN reactively coated by diethylamine get the best effects compared with the others, the rate of moisture absorption decline by 60.5% and 63.6% respectively in the atmosphere of relative humidity 75.3% and 92.5% in 8 h, and the polar component of surface free energy decline by about 87%, and the nonpolar component increase by about 145%. Using these reactively coated PSAN particle in the BAMO-THF/PSAN propellants, it is found that the propellants using the PSAN coated by ethylenediamine have the best mechanical properties, the maximum stress (σ_m) can be obtained at 0.2% coating mass of ethylenediamine, the maximum stress increased by about 46%, and the elongation (ε_m) increased by about 83%.