The high softening point and mosaic optical textures of coal tar pitch (CTP)-derived mesophase pitches are the main factors limiting their application in high performance carbon fibers. Spinnable mesophase pitch was prepared using CTP hydrogenation process, and the effect of hydrogenation process on the preparation of mesophase pitch and the crystal structure of carbon fibers was investigated. Molecular structure characterization results show that the naphthenic structures and the aliphatic groups in hydrogenated CTP were generated by the hydrogen addition reaction of aromatic rings and the subsequent naphthenic cracking reactions, respectively. The naphthenic structures and aliphatic groups introduced during the CTP hydrogenation process of CTP have a significant effect on improving the homogeneity of anisotropic textures, molecular weight distributions and the molecular stacking heights of mesophase pitches. The prepared mesophase pitch has lower viscosity and enhanced flowability, significantly improving its spinning stability and the molecular orientation of their as-spun pitch fibers. Benefits from this, the optimized carbon fibers present distorted graphite lamellar structures and possess a larger crystal size than commercial coal tar-based carbon fibers K13D2U. The work provides some valuable insights for enhancing crystal structures of carbon fibers via molecular structure regulations of their precursors.

煤焦油沥青（CTP）衍生的中间相沥青的高软化点和马赛克光学织构是限制其在高性能碳纤维中应用的主要因素。采用CTP加氢工艺制备可纺中间相沥青，并研究加氢工艺对中间相沥青制备及碳纤维晶体结构的影响。分子结构表征结果表明，氢化CTP中的环烷结构和脂肪族基团分别是由芳环的加氢反应和随后的环烷裂解反应生成的。CTP加氢过程中引入的环烷结构和脂肪族基团对于提高各向异性织构的均匀性有显着效果，中间相沥青的分子量分布和分子堆积高度。所制备的中间相沥青具有较低的粘度和增强的流动性，显着提高了其纺丝稳定性和初纺沥青纤维的分子取向。受益于此，优化后的碳纤维呈现出扭曲的石墨层状结构，并且比商用煤焦油基碳纤维K13D2U具有更大的晶体尺寸。这项工作为通过其前体的分子结构调控来增强碳纤维的晶体结构提供了一些有价值的见解。受益于此，优化后的碳纤维呈现出扭曲的石墨层状结构，并且比商用煤焦油基碳纤维K13D2U具有更大的晶体尺寸。这项工作为通过其前体的分子结构调控来增强碳纤维的晶体结构提供了一些有价值的见解。受益于此，优化后的碳纤维呈现出扭曲的石墨层状结构，并且比商用煤焦油基碳纤维K13D2U具有更大的晶体尺寸。这项工作为通过其前体的分子结构调控来增强碳纤维的晶体结构提供了一些有价值的见解。