两种不同原料中间相沥青分子结构的研究

MOLECULAR STRUCTURES OF MESOPHASE PITCHES PREPARED FROM DIFFERENT RAW MATERIALS

采用偏光显微镜、族组成分析、红外光谱(FI-IR)、核磁共振(NMR)等研究手段,对两种不同中间相沥青FCC-MP(石油渣油热缩聚中间相沥青)和AR-MP(萘系催化合成中间相沥青)的组成结构进行研究,结果表明:100%中间相沥青在稠环芳烃区都有3个平行的红外特征峰(870,810,750cm-1),且3个吸收峰的强度相近;FI-IR和NMR测试都表明,不同中间相沥青的支链比例差别很大,AR-MP分子上含有较多的甲基支链和环烷结构,非芳香碳占总碳原子的21%,FCC-MP分子上的支链和环烷比例较少,非芳香碳占总碳原子的14%,分子结构中支链和环烷结构有利于形成大融并体,降低软化点和熔融态黏度;根据1H-NMR和13C-NMR谱图计算出两种沥青吡啶可溶物(PS)的H、C分布数据和分子结构参数,并推导出两种中间相沥青PS组分的平均分子结构模型。

The characters of molecular structures of mesophase pitches prepared from different raw materials, FCC- MP（prepared by two- stage thermal condensation method from FCC slurry） and AR- MP（prepared catalytically from naphthalene）, are analyzed using polarized microscope,fraction analysis, FI-IR,NMR, and etc. The results indicate that three bands at 870, 810 and 750 cm^-1 in IR spectra were observed in 100% mesophase pitches which reflects aromatic hydrogen. In comparison with FCC- MP, AR-MP possesses more alkyl and naphthenic groups which are about 21% among total carbons. Such groups are favorable for the formation of bulk mesophase which are essential for the mesophase pitch with low softening point and low viscosity. Average molecular structure parameters and models of PS fraction of FCC -MP and AR- MP were obtained from ^1H- NMR and ^13C -NMR spectra.