A self-shielded electron beam (EB) accelerator was connected to the front of a pre-oxidation furnace to evaluate the effect of radiation on the pre-oxidation of polyacrylonitrile (PAN) fibers; with this setup, PAN fibers could be irradiated and pre-oxidized in sequence to obtain stabilized fibers. Radiation effects during different temperature stages of the pre-oxidation process were analyzed by differential scanning calorimetry, Fourier-transform infrared spectroscopy, and electron spin resonance spectroscopy. The results indicated that radiation exerted significant but different effects at various stages of the pre-oxidation process. The alkane radicals induced by radiation are rapidly transformed into polyene structures and produced polyenyl radicals after a short heat treatment period. The polyenyl radicals promoted dehydrogenation and cyclization reactions and polyene structures improved the thermal stability of the PAN fibers. Therefore, radiation can greatly shorten the time required for the stabilization of PAN fibers, owing to which the time needed for each temperature stage can be reduced by a large extent. The effects of radiation on various temperature stages of the pre-oxidation process were analyzed accurately by studying the changes in the concentration of polyenyl radicals. An optimized pre-oxidation process for irradiated PAN fibers was designed, which reduced the time period required for stabilization by 75%. The optimized pre-oxidation plus continuous EB irradiation process induced good properties in the stabilized PAN fibers, in terms of fiber density, oxygen content, and degree of cyclization. Radical concentration was found to be an appropriate indicator to express the degree of pre-oxidation.

将自屏蔽电子束（EB）加速器连接到预氧化炉的前部，以评估辐射对聚丙烯腈（PAN）纤维预氧化的影响。通过这种设置，可以依次对PAN纤维进行辐照和预氧化，以获得稳定的纤维。通过差示扫描量热法，傅里叶变换红外光谱和电子自旋共振光谱分析了预氧化过程中不同温度阶段的辐射效应。结果表明，辐射在预氧化过程的各个阶段发挥了重要但不同的作用。在短时间的热处理后，由辐射诱导的烷烃自由基迅速转变为多烯结构并产生多烯基自由基。多烯基促进了脱氢和环化反应，多烯结构改善了PAN纤维的热稳定性。因此，辐射可以大大缩短稳定PAN纤维所需的时间，因此可以大大减少每个温度阶段所需的时间。通过研究多烯基自由基浓度的变化，可以准确地分析辐射对预氧化过程各个温度阶段的影响。设计了用于辐照PAN纤维的优化预氧化工艺，将稳定所需的时间减少了75％。在纤维密度，氧含量和环化程度方面，优化的预氧化加连续EB辐照过程在稳定的PAN纤维中具有良好的性能。