PAN纤维在特征碳化温度下的反应特性

Reaction character of PAN fibers at characteristic carbonization temperature

通过TG-MS、XPS和元素分析等手段研究了低温碳化PAN纤维的碳化特征温度以及特征温度下纤维的反应特性。1100℃为高温碳化反应的特征温度,纤维在此温度下存在最大失重速率,1100℃后纤维裂解释放的主要是氮气。1100℃延长时间,纤维中氨基/亚氨基氮、吡啶氮和类石墨氮都不断减少,部分吡啶氮转化为类石墨氮。1100℃处理后纤维密度大幅度增长,恒温24s后迅速减小;恒温24s内纤维中石墨微晶晶面尺寸随时间延长迅速增大,24s后增长速率逐渐变缓;1100℃进行恒温热处理,24s前以缩聚反应为主,24s后以裂解反应为主。

The characteristic carbonization temperature and structures at this temperature was investigated. The fibers of PAN fibers was proposed and evolution of the composition structure changes caused by different types of chemical reaction were discussed. The results indicated that 1100℃ was characteristic temperature for carbonization process of PAN fibers. Maximum mass loss rate was appeared at about this temperature. N in three bonding states as the pyridine nitrogen, amino （or imino） and graphite-like nitrogen decreased with extended heating time. Decreasing rate of pyridine nitrogen was slower than that of graphite-like due to some pyridine nitrogen converted to graphite-like nitrogen. The density increased more after heat treated at 1l00℃ ,but decreased rapidly above 24s. The crystal dimension increased rapidly before 24s,but slower after 24s. At 1100℃, condensation polymerization was the leading reaction under 24s, and then pyrolysis reaction was the dominant reaction.