纺丝沥青的性质决定其能否连续、稳定工业化生产沥青基碳纤维，也是影响碳纤维性能的重要因素，而合成方法是调控纺丝沥青性质的重要手段。对比传统热缩聚法，氯化-脱氯化法可以从分子维度调控合成，以制得纺丝性优异的沥青前驱体。迄今，针对采用热缩聚法和氯化-脱氯化法合成的纺丝沥青分子结构特征差异研究鲜有报道。采用元素分析、傅里叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）、基质辅助激光解吸/电离飞行时间质谱（MALDI TOF-MS）及固态核磁共振（13C-NMR）表征纺丝沥青的分子组成与结构，采用平均分子模型方法构建纺丝沥青的分子模型。结果表明，采用氯化-脱氯化法合成的纺丝沥青具有更高的碳含量，且在FTIR中1 490和696 cm-1波长处和XPS C1s中287.1 eV结合能处均表现出特有由氯化反应产生的特征峰；由MALDI TOF-MS和13C-NMR 分析可知，由氯化-脱氯化法合成的纺丝沥青具有更高的聚合度、分子量和芳香度，其平均分子量达857，芳香度达0.87，且纺丝沥青的分子结构更趋向于在一维方向上发展的线性结构。根据表征分析结果，采用Shoolery-Budde提出的平均分子模型，构建了由氯化-脱氯化法和热缩聚法合成的纺丝沥青的分子模型。

The property of spinnable pitch is a significant factor in determining continuously and stably industrial production of pitch-based carbon fiber, and it also affects largely the performance of final carbon fiber. Generally, the synthesis method is an important means to control the property of spinning pitch. Compared to the method of thermal polycondensation, chlorination-dechlorination method can controllably synthesize spinnable pitch from the molecular dimension to improve the spinnability. However, there are few reports on the differences in the molecular structure characteristics of spinnable pitches synthesized by thermal polycondensation and chlorination-dechlorination methods, respectively. In this work, the molecular composition and structure of the spinnable pitches were determined by elemental analysis, Fourier transforms infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF-MS), and solid-state nuclear magnetic resonance (13C-NMR). The average molecular model method was used to construct the molecular model of spinning pitch. The results show that the spinnable pitch synthesized by the chlorination-dechlorination method has higher carbon content and the characteristic peaks is shown at 1 490 cm-1 and 696 cm-1 and XPS C 1s spectra at 287.1 eV in FTIR spectra. From MALDI TOF-MS and 13C-NMR analysis, spinnable pitch synthesized by chlorination-dechlorination has a higher polycondensed degree, molecular weight, and carbon aromaticity, with the average molecular weight of 857, and the carbon aromaticity of 0.87. The molecular structure of the spinnable pitch tends to be more linear in the one-dimensional direction. According to the results of characterization analysis, the molecular models of spinnable pitch synthesized by chlorination-dechlorination and thermal polycondensation were established using the average molecular model proposed by Shoolery-Budde.

0 引言

1 材料与表征

   1.1 纺丝沥青的合成

   1.2 表征分析

2 结果与讨论

3 结论