高聚合度聚磷酸铵中特征磷的31P核磁共振分析

Analysis of Characteristic Phosphorus in High Polymerization Ammonium Polyphosphate by 31P NMR

采用一维31P核磁共振(31P NMR)、二维J分解谱(J-resolved)和扩散核磁(31P DOSY)等方法,研究了高聚合度聚磷酸铵(APP)和多聚磷酸盐的特征磷及其偶合常数.研究表明,多聚磷酸盐及其中所含的二聚磷酸盐端基磷分别呈双峰和单峰特征,多聚磷酸盐自旋偶合裂分的端基磷共振峰的偶合常数为19.4 Hz.APP中含有小分子二聚磷酸铵和正磷酸铵,用31P NMR定量表征APP聚合度时需排除二聚体端基磷峰的面积.在100℃水中溶解APP制备的APP水溶液中,部分高聚合度APP发生断链,中间磷共振峰处出现短链APP的磷共振峰.

In this paper,phosphorus nuclear magnetic resonance(31P NMR),J-resolved and 31P-DOSY are used to study the characteristic phosphorus and coupling constants of APP.Studies have shown that the endgroup phosphors of polyphosphate and diphosphate have double-peak and single-peak characteristics respec⁃tively,and the coupling constant of spin-coupled peak is 19.4 Hz;Ammonium phosphate(Ⅱ-APP)contains ammonium di-polyphosphate and ammonium orthophosphate.When 31P NMR is used to quantitatively charac⁃terize the degree of APP polymerization,the terminal phosphorus of ammonium di-polyphosphate should be ex⁃cluded;when APP is prepared by dissolving APP in water at 100℃,the appearance of the phosphorus reso⁃nance peak of small molecule middle phosphorus proves that APP has partially broken chain.