The evolution of structures and properties of Polyacrylonitrile (PAN) precursor fiber during the thermal stabilization was directly related to the mechanical properties of carbon fiber. In the present study, the effects of stretching on the orientation structure and reaction behavior of PAN fibers at different thermal stabilization stages were experimentally investigated. The multi-dimensional structural characterization and mechanical properties tests were used, such as XRD, FT-IR, ¹³C-NMR, Raman and material testing machine, etc, which would help to reveal the evolution mechanism of the microstructure and reaction behavior of PAN fiber during the thermal stabilization. The results showed that in the process of thermal stabilization, stretching caused the rearrangement of crystalline orientation structure, promoted the cyclization reaction process at higher temperature (>200 C), and furthermore promoted the formation of oriented aromatic like lamellar structure. It can be found that when the drawing ratio of 10% and the exposed temperature at 200 C were applied to the PAN fiber, the increasing of crystalline orientation was obvious and more aromatic lamellar structures generated. Based on the above process technology, the carbon fiber with the higher graphitization degree and better mechanical properties was finally obtained.

聚丙烯腈（PAN）前驱体纤维在热稳定过程中结构和性能的演变与碳纤维的力学性能直接相关。在本研究中，通过实验研究了拉伸对 PAN 纤维在不同热稳定阶段的取向结构和反应行为的影响。使用了多维结构表征和力学性能测试，如 XRD、FT-IR、¹³C-NMR、拉曼和材料试验机等，有助于揭示PAN纤维在热稳定过程中的微观结构和反应行为的演变机制。结果表明，在热稳定过程中，拉伸引起晶体取向结构的重排，促进了较高温度（>200℃）下的环化反应过程，进一步促进了取向芳香状层状结构的形成。可以发现，当拉伸比为 10% 和暴露温度为 200 ℃ 时，PAN 纤维的结晶取向增加明显，并产生更多的芳香层状结构。基于以上工艺技术，