Naphthene-based aromatic-rich fraction was modified by tetrahydronaphthalene and polyethylene glycol to obtain modified materials which were selected to prepare mesophase pitches by a direct condensation method. The structural composition of modified materials were characterized by simulated distillation (SIMDIS), elemental analysis, Fourier transform infrared spectrometry (FTIR) and ¹H nuclear magnetic resonance (¹H NMR) spectroscopy. Influences of the naphthenic structures and alkyl chains in modified materials on the formation and development of mesophase structures were investigated by analyzing variations in optical texture, softening point, carbon residue, molecular and microcrystal structure of mesophase pitch. Results showed that the alkyl structures in modified materials treated by tetrahydronaphthalene and polyethylene glycol were mainly naphthenic structures and alkyl chains, respectively. The existence of alkyl structures in modified materials was beneficial for the formation of mesophase with high quality. Moreover, the naphthenic structures had a better improving effect than alkyl chains. Abundant naphthenic structures or an appropriate amount of alkyl chains in feedstock contributed to the preparation of mesophase pitch with large domain structure, low softening point, high carbon residue and ordered microcrystal structure.

中文翻译：

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环烷基富芳烃馏分的加氢烷基化改性及其对中间相发展的影响

采用四氢萘和聚乙二醇对环烷基富芳烃馏分进行改性，得到改性材料，选用直接缩合法制备中间相沥青。通过模拟蒸馏（SIMDIS）、元素分析、傅里叶变换红外光谱（FTIR）和¹ H核磁共振（¹H NMR)光谱。通过分析中间相沥青的光学织构、软化点、残碳、分子结构和微晶结构的变化，研究了改性材料中环烷结构和烷基链对中间相结构形成和发展的影响。结果表明，经四氢萘和聚乙二醇处理的改性材料中的烷基结构分别以环烷结构和烷基链为主。改性材料中烷基结构的存在有利于高质量中间相的形成。此外，环烷结构比烷基链具有更好的改善效果。