Abstract Isotropic pitch-based carbon fibers (IPCFs) were prepared at various carbonization temperatures from 400 to 1200 °C using pitch fibers stabilized at 290 °C to investigate their structural evolution during the carbonization process. The chemical structure changes of IPCFs as a function of carbonization temperature were thoroughly analyzed using various characterization tools, such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and laser desorption/ionization time-of-flight mass spectrometry. The characterization results were systematically compared with those of the ordering structures obtained from Raman spectroscopy and X-ray diffraction. The results demonstrated that the transformation of the chemical structure, ordering structure, and physical properties of IPCFs proceeds with three distinct steps depending on the carbonization temperature: fusion of small aromatic structures of pitch, random stacking of the fused structure and conversion into mostly disordered carbon structures. In addition, we found a correlation of the chemical and ordering structure changes with the enhancement of physical properties, such as density, tensile modulus, and strength.

中文翻译：

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沥青纤维在低温碳化过程中的结构演变

摘要 使用稳定在 290 °C 的沥青纤维在 400 至 1200 °C 的不同碳化温度下制备各向同性沥青基碳纤维 (IPCF)，以研究它们在碳化过程中的结构演变。使用各种表征工具，如傅里叶变换红外光谱、X 射线光电子能谱和激光解吸/电离飞行时间质谱，彻底分析了 IPCF 的化学结构变化作为碳化温度的函数。将表征结果与从拉曼光谱和 X 射线衍射获得的有序结构进行了系统比较。结果表明，化学结构、有序结构、IPCFs 的物理性质根据碳化温度进行三个不同的步骤：沥青的小芳香结构的融合、融合结构的随机堆叠和转化为大部分无序的碳结构。此外，我们发现化学和有序结构的变化与物理性质（如密度、拉伸模量和强度）的增强之间存在相关性。