Effects Of Acrylic Potassium Slat Polymer On The Phase Stabilization Of Ammonium Nitrate

Polycrystallinity and moisture absorption of Ammonium nitrate (AN) limited its application in industry, agriculture and national defense seriously. The phase stabilization of Ammonium nitrate became the key to solution the problem of polycrystallinity of ammonium nitrate in workable temperature range. According to the effect of high valent cationic and polymer on phase transition behavior of ammonium nitrate, this thesis focused on using the acrylic potassium slat polymer to prepare Phase Stabilized of Ammonium Nitrate (PSAN), that could eliminate transition temperature of ammonium nitrateⅣ-Ⅲphase at 32.3℃and increase theⅢ-Ⅱphase transition temperature from 84.2℃to 100℃. Then compared the modified and unmodified relevant properties of AN, and discussed the mechanism of the phase stabilization.The results show that the acrylic potassium slat polymer with molecular weight between 1×105～1×106 was obtained when 25% of monomer concentration, initiator 0.5%,25℃, pH12～13; When the addition of acrylic potassium salt polymer equal or greater than 1.1% (mass percentage), the ammonium nitrateⅣ-Ⅲphase transition temperature at 32.3℃can be eliminated, and theⅢ-Ⅱphase transition temperature was increased from 84.2℃to 100℃; When the addition equal or greater than 2.0%(mass percentage), the absorption rate of ammonium nitrate was decreased 9.64%. In contrast of acrylic resin, It was found that only when addition of polypotassium methacrylate to 1.5%(mass percentage), the ammonium nitrateⅣ-Ⅲphase transition temperature at 32.3℃can be eliminated, and theⅢ-Ⅱphase transition temperature was increased from 84.2℃to 100℃, but the absorption rate decreased 0.97%; Polyacrylamide (PAM) can inhibit ammonium nitrateⅣ-Ⅲphase transition temperature at 32.3℃and theⅢ-Ⅱphase transition temperature at 84.2℃, but decreased the absorption rate for 11.90%. Comprehensive consideration from phase transition, moisture absorption, thermal stability and a series of factors, acrylic potassium slat polymer was considered as a good phase polypropylene stabilizer.The research showed that the mainly mechanism of acrylic potassium slat polymer as a phase polypropylene stabilizer was:On the one hand, the destruction of the original cell structure due to the replacing of NH4+ to K+ prevented theⅣ-Ⅲphase transition of ammonium nitrate, and increased the temperature ofⅢ-Ⅱphase transition; the other hand, acrylic potassium slat polymer attached to the surface of ammonium nitrate and formed a layer of hydrophobic protective film.