用差示扫描量热仪(DSC)研究了聚丙烯腈/衣糠酸共聚物纤维在氧化性气氛(空气)和非氧化性气氛(氩气)下环化反应和氧化反应受升温速率的影响,分析了这两种反应之间的相互作用和反应机理;结合傅里叶红外光谱(FTIR)对DSC回收样品的分析研究了环化反应的诱导期。结果表明,环化反应的引发存在一定的诱导期,升温速率越快,诱导期越长;在缓慢升温条件下,氧的充分扩散使一部分氧化反应与环化反应可以同时进行;在预氧化初期,氧化性气氛具有引发环化反应、缩短环化反应诱导期的作用,而在预氧化后期则阻碍环化,这种阻碍作用随着升温速率的提高而逐渐减弱。
Abstract
The effects of heating rates on the cyclization and oxidation reactions of polyacrylonitrile/itaconic acid copolymer fibers under oxidative(air) and non-oxidative(argon) atmospheres were investigated by differential scanning calorimetry(DSC).The interaction between the two reactions and their mechanisms are analyzed.Fourier transform infrared spectroscopy(FTIR) was used to study the induction period of cyclization reaction.The results show that ther induction period is existed before the cyclization reaction initiated.The higher the heating rate,the longer the reduction period.With slow heating rate,the diffusion of oxygen facilitates that a part of oxidation is taken place with the cyclization reactions simultaneously.At the beginning of pre-oxidation process,oxygen can initiate the cyclization reaction and shorten the reduction period.However at the late stage,oxygen retards the cyclization reaction,but the retardant role is weakens with increasing of heating rate.
关键词
碳纤维 /
预氧化 /
动力学 /
诱导期
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Key words
carbon fiber /
pre-oxidation /
kinetics /
induction period
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脚注
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基金
国家自然科学基金(50902088);山东省自然科学基金(ZR2009FQ013);国际科技合作项目(2009DFR50600)
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