聚合物对硝酸铵相转变的影响

Effects of Polymers on Phase Transition of Ammonium Nitrate

硝酸铵(AN)在常压下有五种晶型,温度变化时晶型要发生转变,导致使用性能降低。为抑制或防止AN发生某种相转变,在AN中添加0.99%的六种不同类型聚合物,用差式扫描量热法(DSC)研究聚合物对AN相转变的影响。结果表明,聚对苯乙烯磺酸钠-丙烯酸聚合物对AN的相转变影响较小,聚对苯乙烯磺酸钠-丙烯酸十二酯聚合物可有效防止AN发生Ⅳ-Ⅲ相转变,聚对苯乙烯磺酸钠、丙烯酸十二酯、聚对苯乙烯磺酸钠-N,N-二甲基二烯丙基氯化铵和聚对苯乙烯磺酸钠-丙烯酸十二酯-N,N-二甲基二烯丙基氯化铵可有效防止AN发生Ⅲ-Ⅱ相转变。聚合物对AN相转变的影响在于聚合物可加强AN的氢键网络并阻碍AN分子中NO3-的转动。

In order to restrain or prevent AN phase transition,six kinds of polymers were added to AN samples and the effects of polymers on AN phase transition were studied by differential scanning calorimetry （DSC） method. The results show that sodium p-ethylene benzenesulfonate-acrylic acid polymer has little effect on AN phase transition, while sodium p-ethylenebenzene sulfonate-dodecyl acrylate polymer prevents the transition of Ⅳ-Ⅲ effectively. And sodium p-ethylene benzenesulfonate polymer, dodecyl acrylate, sodium p-ethylenebenzenesulfonate-N, N-dimethyldiallyl ammonia chloride polymer and sodium p-ethylenebenzenesulfonatedodecyl acrylate-N,N-dimethyldiallyl ammonia chloride polymer prevent the transition of Ⅲ- Ⅱ effectively. The effect of polymer on AN phase transition results from that polymer strengthens the hydrogen-bond network and baffle the turn of NO3 ^-.