中间相沥青分子结构对其可纺性和纤维结构的影响

Influence of molecular structure of mesophase pitch on its spinnability and structure of carbon fibers

中间相沥青(MP)结构是获得高性能中间相沥青基石墨纤维(MPGF)的关键。为探究中间相沥青分子结构对其可纺性及纤维结构的影响,本文以2种中间相沥青(MP1和MP2)为研究对象,对比分析了它们的分子结构特征、可纺性和所得石墨纤维结构之间的差异。研究结果表明,分子量大、分子平面刚性强、侧基和环烷基占比少的MP1,倾向于获得石墨微晶呈褶皱状紧密规整排列且尺寸较大的MPGF;而分子量相对小、烷基结构含量相对高的MP2,具有更低的可纺温区,所获得的MPGF中石墨微晶尺寸较小且沿纤维径向呈辐射状排列。

The structure of mesophase pitch(MP)is the key for high-performance mesophase pitch-based graphite fiber(MPGF).In order to investigate the influence of molecular structure of MP on the spinnability and structure of carbon fibers,two MPs(MP1 and MP2)were studied comparatively.The differences of their molecular structure characteristics,spinnability and the structures of the corresponding graphite fibers were analyzed.The results show that MP1 has relatively high molecular weight,high molecular plane rigidity with less contents of alkyl chains and naphthenic groups.As a result,the graphite microcrystals in the obtained GFs originated from MP1 are more regular with big size,and arrange in a disorganized folded-layer structure.On the contrary,MP2 with relatively smaller molecular weight,has higher contents of side alkyl and naphthenic structures.Thus,MP2 has a lower spinnable temperature zone compared with MP1,and the obtained graphite fibers have relatively smaller graphite microcrystals that show a radial arrangement.