摘要
将聚丙烯腈(PAN)原丝置于空气中在180℃~265℃温度范围内逐步预氧化,同时控制适当的牵伸比。利用广角X射线衍射(XRD)、定量傅里叶红外光谱(FTIR)、差示扫描量热分析(DSC)和热失重分析(TG)手段考察了连续预氧化过程中纤维微晶结构、化学反应和热性能的变化。结果表明:(1)PAN纤维在空气中外力场作用下进行氧化稳定化,200℃之前环化反应缓慢进行;在200℃~230℃温度范围内,环化度呈线性迅速提高,反应加剧;230℃之后,环化反应减慢;(2)预氧化反应按序态进行,首先发生在无序的非晶区,逐步向有序区演变;一旦有序区发生反应,则反应剧烈;(3)在210℃之前,微晶尺寸增大,符合应力场结晶理论;210℃之后,晶粒尺寸迅速减小。
Polyacrylonitrile fibers were pre-oxidized in air at temperatures from 180 degrees C to 265 degrees C. The morphological rearrangement, chemical reactions and the variation of thermal properties during the continuous thermal oxidative stabilization were characterized by X-ray diffraction, FT-IR, DSC and TG. Results showed that; (1) When the pre-oxidative temperature was below 200 degrees C,the cyclization reaction was slow. When the temperature increased from 200 degrees C to 230 degrees C, the cyclization index increased rapidly and the reaction was drastic. The reaction rate reduced after the pre-oxidative temperature reached above 230 degrees C. (2) The pre-oxidation reactions were first initiated in an amorphous region, thereafter the reactions propagated to the crystalline regime at high temperatures where reactions were drastic. (3) When the pre-oxidative temperature was below 210 degrees C, the crystal size increased, corresponding to stress crystallization. The crystallite size decreased rapidly after the pre-oxidative temperature reached above 210 degrees C.
出处
《新型炭材料》
SCIE
EI
CAS
CSCD
北大核心
2005年第2期144-150,共7页
New Carbon Materials
基金
国家自然科学重点基金(50333070)~~
关键词
聚丙烯腈纤维
预氧化
微晶结构
polyacrylonitrile fibers
pre-oxidization
crystallitic structure