无机阻燃剂高聚合度聚磷酸铵的研制

以五氧化二磷、磷酸铵盐、尿素为原料、氨气为保护气,制备了高聚合度聚磷酸铵无机阻燃剂。考察了五氧化二磷、磷酸铵盐、尿素的用量和反应温度对聚磷酸铵平均聚合度的影响。采用端基滴定法测定了聚磷酸铵的聚合度,并用X射线衍射(XRD)法表征了聚磷酸铵的晶体结构,同时测定了聚磷酸铵的粒度和溶解度。实验结果表明,制备聚磷酸铵的最佳反应条件为:n(磷酸氢二铵)∶n(五氧化二磷)∶n(尿素)=1∶1∶0.3,反应温度280~300℃,反应时间40m in,热处理温度250~280℃,热处理时间110m in。在此条件下制备的聚磷酸铵的平均聚合度大于600,平均粒径直径小于50μm,在水中的溶解度小于0.4g;XRD表征结果表明,所合成的物质为Ⅱ型聚磷酸铵。

Preparation of Ammonium Polyphosphate with High Polymerization Degree as Inorganic Fire Retardant

Ammonium polyphosphate(APP)with high polymerization degree,as a inorganic fire retardant used in plastic processing and fire extinguishing,was prepared from phosphorus pentoxide(P_2O_5),phosphates of ammonium and urea(CO(NH_2)_2)in NH_3 atmosphere.Effects of raw material amount and reaction temperature on polymerization degree of APP were investigated.Polymerization degree of products was measured by means of end group titration.Crystal phases of products were also characterized by means of X-ray diffraction(XRD).Granularity and solubility of APP were also measured.Under optimal conditions:n((NH_4)_2HPO_4) ∶n(P_2O_5) ∶n(CO(NH_2)_2)=1 ∶1 ∶0.3,reaction temperature 280～300℃,reaction time 40min,thermal treatment temperature 250～280℃,thermal treatment time 110min,average polymerization degree of prepared APP could reach more than 600,particle diameter less than 50μm and solubility less than 0.4g.XRD result identified the prepared product as APP-Ⅱ.