PAN纤维高温环境下氮结合态演变规律的研究

Research on evolution of the combination state of N in PAN fibers in a high-temperature environment

通过使用XPS和XRD等表征手段研究了经低温碳化后PAN纤维中氮结合态的高温演变规律,推测了其反应机理,探讨了由氮结合态的演变所引起的纤维结构变化。结果表明:经低温碳化后PAN纤维中的氮主要以吡啶氮、叔胺氮和氨基/亚氨基3种结合态存在,当热处理温度在700℃以下时,纤维中吡啶氮含量最多;随着温度的升高,氨基/亚氨基和吡啶氮含量逐渐减少,而叔胺氮含量先呈增加趋势,温度升高到1000℃以后时,叔胺氮含量迅速下降;1300℃以后,纤维中的叔胺氮含量最多;PAN纤维中的氮以叔胺氮形式存在更有利于平面六元碳网的逐步完善。

The high-temperature evolution of the combination state of N in PAN fibers through carbonization in a low temperature was studied,the reaction mechanism was speculated,and the fibers structure changes caused by the evolution of the combination state of N was discussed.The results indicated that N in PAN fibers through carbonization in a low temperature existed in three combination states as the pyridine nitrogen,amino（or imino） and graphite-like nitrogen.The pyridine nitrogen content was the most when the heat treatment temperature was below 700℃.With the increase of the heat-treatment temperature,amino（or imino） and the pyridine nitrogen content decreased,while the tertiary nitrogen content increased at first and then decreased quickly when the temperature was higher than 1000℃.When the heat-treatment temperature was above 1300℃,the tertiary nitrogen content was the most.N in PAN fibers existed in the tertiary nitrogen was better for the improvement of the plane six carbon net.