磷酸二氢铵-尿素缩聚法制备聚磷酸铵研究

摘要

采用磷酸铵盐-尿素脱水聚合法制备聚磷酸铵,通过单一变量的方法讨论反应时间、反应温度、配料比等因素对聚磷酸铵产品性能的影响.分别采用重量法测定产品的磷含量,蒸馏法测产品的含氮量,端基滴定法来确定产品的平均聚合度,并通过XRD验证聚磷酸铵产品的晶型.实验结果表明,最佳工艺条件为:原料配比[n(磷酸二氢铵)∶n(尿素)]为1∶1.1,反应时间为1.5 h,反应温度为260℃,在此条件下所得聚磷酸铵产品磷质量分数能达到73.1％,氮质量分数能达到14.6％,平均聚合度为46.9,完全达到Ⅰ型工业聚磷酸铵要求.%Ammonium polyphosphate was synthesized by ammonium phosphate-urea dehydration polymerization method.The effects of reaction time,reaction temperature,and batching ratio on the properties of ammonium polyphosphate product were discussed by a single variable method.The phosphorus content of the product was determined by gravimetric method,the nitrogen content of the product was determined by distillation method,the average degree of polymerization of the product was determined by terminal titration method,and crystal shape of the product was verified by XRD.The experimental results showed that the optimum conditions were as follows:the ratio of raw materials (the ratio of amount of substance of ammonium phosphate to urea) was 1∶1.1,the reaction time was 1.5 h,the reaction temperature was 260 ℃,the phosphorus mass fraction could reach 73.1％,nitrogen mass fraction could reach 14.6％,and the average degree of polymerization of 46.9,fully meet the requirements of ammonium polyphosphate type Ⅰ.