This study investigates the synthesis of mesophase pitch (MP) with varying anisotropic (mesophase) content of 19–74% by thermal soaking of isotropic coal tar pitch for different time intervals at 410 °C without using any catalyst/additive and pre-treatment processing. These mesophase pitches were converted into continuous pitch fibers by melt spinning process, then stabilized in air and carbonized at 1000 °C to obtain the carbon fibers. The anisotropic (mesophase) content increases with increasing soaking time period from 11 to 15 h and as a result, alter the various microstructural properties of carbon fibers. Physio-chemical and microstructural properties of prepared MP were systematically studied with TGA, FTIR, Raman spectroscopy, XRD and ¹H‐NMR. The overall result suggested enhancement in aromaticity and naphthenic hydrogen with increased anisotropy. Rheological studies were carried out to understand the spinning behavior of MPs. Furthermore, transformation of mesophase pitch into carbon fibers at 1000 °C, showed a decline in the microcrystal properties due to the evolution of gases which create disorderness in the lattice structure. It was observed that the increased anisotropic content improves the microstructure of the mesophase pitch and their resultant carbon fibers as the microstructure attained during mesophase formation is retained during its carbonization.

本研究在不使用任何催化剂/添加剂和预处理工艺的情况下，通过在 410 °C 下对各向同性煤焦油沥青进行不同时间间隔的热浸泡，研究了各向异性（中间相）含量为 19-74% 的中间相沥青 (MP) 的合成. 这些中间相沥青通过熔融纺丝工艺转化为连续的沥青纤维，然后在空气中稳定并在1000℃下碳化以获得碳纤维。各向异性（中间相）含量随着浸泡时间从 11 小时增加到 15 小时而增加，结果改变了碳纤维的各种微观结构特性。^{用 TGA、FTIR、拉曼光谱、XRD 和1}系统地研究了制备的 MP 的物理化学和微观结构特性H-NMR。总体结果表明芳香性和环烷氢随着各向异性的增加而增强。进行流变学研究以了解 MP 的旋转行为。此外，在 1000 °C 下，中间相沥青向碳纤维的转变表明，由于气体的释放导致晶格结构无序，微晶性能下降。据观察，增加的各向异性含量改善了中间相沥青及其所得碳纤维的微观结构，因为在中间相形成期间获得的微观结构在其碳化过程中得到保留。