聚丙烯腈纳米纤维的辐射氧化及热性能变化

采用静电纺丝法制备出平均直径300nm左右的聚丙烯腈(PAN)纤维,利用γ射线在室温及空气气氛中对PAN纳米纤维进行辐照处理,吸收剂量50~500kGy。采用红外光谱仪、X射线光电子能谱仪、差示扫描量热仪及热失重分析仪研究了辐射氧化对PAN纳米纤维结构以及热性能的影响。结果表明,辐射氧化可直接在PAN纳米纤维分子链上引入含氧官能团,有利于预氧化过程中脱氢反应的发生。同时可在室温下引发PAN纳米纤维的部分环化反应生成-C=N-共轭结构,其含量随吸收剂量的增加而增加,可有效降低环化放热峰的强度并缓和放热行为。这些结果表明辐射氧化工艺在碳纳米纤维制造领域有很好的潜在应用价值。

Radiation Oxidation and Subsequent Changes in Thermal Properties of Polyacrylonitrile Nanofibers

Polyacrylonitrile (PAN) nanofibers with the average diameter of 300 nm were fabircated via electronspinning process.PAN nanofibers were irradiated at 50～500 kGy in air at room temperature by γ-rays.The effect of radiation oxidation on the structure of PAN nanofibers and subsequent thermal properties were mainly investigated via FT-IR,XPS,DSC and TGA.The results indicate that oxygen containing functional groups can be directly introduced onto the molecular chains of PAN through radiation oxidation,which facilitate dehydrogenation reaction in the preoxidation process.Meanwhile,cyelization of nitrile groups was induced by γ-rays irradiation at room temperature to produce-C =N-conjugate structure which increases with absorbed dose.Radiation leads to a reduction in intensity of the exothermic peaks of cyclization reaction effectively and also moderates the exothermic behavior.These above results indicate that the radiation oxidation process has a good potential application in the manufacturing field of carbon nanofibers.