高分子改性对中间相沥青微观结构及炭纤维力学性能的影响

以富芳烃重馏分油（FCCDO）和聚乙二醇（PEG）为原料，在一定条件下进行共炭化反应得到可纺中间相沥青并制备力学性能优异的碳纤维。借助元素分析、X射线衍射、氢核磁共振等表征手段深入分析PEG添加量对中间相沥青结构组成及碳纤维性能的影响规律，并对共炭化机理进行推测。结果表明，随着PEG添加量增加，所得中间相沥青的软化点降低，收率增加，分子中烷烃结构数量明显增多，同时产物沥青的光学组织由中间相充分发展的广域流线型转化为小域流线型，最后转化为两相（中间相和各向同性相）共存的混合沥青。碳纤维的力学性能随着PEG添加量的增多而呈现先增大后减小的趋势。PEG添加量（w）为5%时可制备出直径为11.4 μm、拉伸强度最高可达2.4 GPa的碳纤维。

EFFECT OF POLYMERS MODIFICATION ON MICROSTRUCTURE OF MESOPHASE PITCHES AND MECHANICAL PROPERTIES OF CARBON FIBERS

Mesophase pitches were synthesized by the co-carbonization of an aromatic-rich heavy oil（FCCDO）and polyethylene glycol（PEG） under certain conditions, and the carbon fibers with excellent mechanical properties were prepared. The effects of PEG addition on the structure and properties of mesophase pitch and carbon fiber were analyzed by means of elemental analysis, X-ray diffraction and hydrogen NMR analysis et al., and the reaction mechanism of co-carbonization was speculated. The results show that with the increase of PEG addition, the softening point of mesophase pitch is gradually decreased, while the pitch yield and the number of aliphatic groups in the pitch molecular are gradually increased. At the same time, the optical structure of pitch was changed from the wide flow domain bulk mesophase to coarse flow domain mesophase, and finally to the mixed pitch with the coexistence of two phases（isotropic and mesophase components）. The mechanical properties of carbon fiber were increased at first and then decreased with the increase of PEG content. Carbon fibers with diameter of 11.4 μm and tensile strength up to 2.4 GPa were prepared by adding 5% PEG.