不同聚合度的聚磷酸铵灭火性能研究*

为考察聚磷酸铵（APP）干粉灭火剂的聚合度对其灭火性能的影响，选用3种不同聚合度的APP，结合其晶体结构、粒度分布及热性能测试，并通过粉体杯式燃烧器进行小尺寸灭火实验，对比3种样品的灭火性能及灭火机理，研究聚合度与其灭火性能的关系。热性能测试结果显示，聚合度的升高会导致APP的热稳定性下降，随着聚合度从80升至1 500，其初始分解温度从326.11 ℃降低至321.54 ℃，失重率从75.21%增加至79.66%。实验结果表明:随着APP聚合度的增加，火焰降温速率升高，最小灭火浓度（MEC）降低，灭火性能增强，当聚合度为1 500时，MEC为118.143 g/m3。聚合度的升高有助于APP在进入火场后更早、更充分地与火焰发生反应，从而使灭火性能得到提升。

Study on fire extinguishing performance of ammonium polyphosphate with different polymerization degrees

In order to investigate the influence of the polymerization degree of ammonium polyphosphate (APP) dry powder fire extinguishing agent on its fire extinguishing performance,three APPs with different degrees of polymerization were selected.Combined with the crystal structure,particle size distribution and thermal performance tests,the small-scale fire extinguishing experiments were carried out by the powder cup-burner.The fire extinguishing performance and fire extinguishing mechanism of three samples were compared,and the relationship between polymerization degree and fire extinguishing performance was studied.The results of thermal performance test showed that the increase of polymerization degree would lead to the decrease of the thermal stability of APP,as the polymerization degree increased from 80 to 1500,the initial decomposition temperature decreased from 326.11 ℃ to 321.54 ℃,and the weight loss rate increased from 75.21% to 79.66%.The experimental results showed that with the increase of APP polymerization degree,the flame cooling rate increased,the minimum fire extinguishing concentration (MEC) decreased,and the fire extinguishing performance enhanced.When the polymerization degree was 1500,the MEC reached 118.143 g/m3.The increase in polymerization degree helps APP to react with the flame earlier and more fully after entering the fire field,thereby improve the fire extinguishing performance.