聚磷酸铵热氧老化机理及寿命预测

为研究热氧对聚磷酸铵(APP)老化降解的影响,对两种品牌的APP进行了人工加速热氧老化处理,利用傅里叶红外光谱、核磁共振表征了APP热氧老化后的结构变化,利用差式扫描量热分析法预测出APP热氧老化寿命。结果表明,APP经热氧老化逐步转化为磷酸二氢铵,老化过程中P—O—P键断裂、P=O键增加,平均聚合度不断下降。APP在常温下寿命较长,可以达到100 a左右,且平均聚合度越高寿命越长。随着使用环境温度的提高其寿命变短,在50℃下寿命不足10 a。实验结果为研究膨胀型钢结构防火涂料的老化机理与耐久性提供参考。

Aging mechanism and life prediction of ammonium polyphosphate thermal-oxidative acceleration aging

To study the effect of thermal-oxidative on the degradation of ammonium polyphosphate（APP）,an artificial accel-erated thermal aging treatment was performed on the APP of the two brands.The Fourier transform infrared spectroscopy and nuclear magnetic resonance were used to characterize the structural changes of APP after thermal oxygen aging.Differential scanning calorimetry predicted heat aging life.The results showed that after thermo-oxidative aging,APP gradually transformed into ammonium dihydrogen phosphate.During the aging process,the P—O—P bond was broken,the P=O bond was increa-sed,and the average degree of polymerization decreased.APP had a long life at room temperature and could reach about 100 years,furthermore,with the higher the average degree of polymerization,the longer the life.With the increase of the ambient temperature,the life is shortened,and the life at 50 ℃ was less than 10 years.The results of the study provided reference for the study of the aging mechanism and durability of the fire-resistant coating for intumescent steel structures.