Preparation of polymer modified phase stable ammonium nitrate

The invention discloses a method for preparing polymer modified phase-stable ammonium nitrate. The method comprises the steps of synthesizing an organic polymer from styrene sodium sulfonate, acrylic ester, dimethyl diallyl ammonium chloride and butene diacid sodium by use of monomers, dissolving an organic monomer in water, stirring and heating the water, dripping initiator, preserving heat, heating, preserving heat, adding the synthetic organic polymer to a ammonium nitrate aqueous solution, heating the solution for dissolution, stirring the solution fast, naturally cooling the solution forcrystallization, drying crystals at a temperature between 50 and 80 DEG C and obtaining the polymer modified phase-stable ammonium nitrate. As the method adds the organic polymer to ammonium nitrate,and as the polymer is low in air permeability and excellent in film-forming property, a film is great in toughness and elasticity, high in strength, capable of bearing volume expansion caused by crystal transition, favorable for stabilizing AN crystal form and good in the effect of inhibiting crystal transition points. The method has the advantages of remarkably reducing the addition of the organic polymer in the ammonium nitrate, having little influence on the explosion properties of modified ammonium nitrate explosive and expanding the application range of ammonium nitrate in the field of industrial explosive and solid propellant.