Sha Yang, Liu Wei, Li Yue, Cao Weiyu
State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, China.
The Key Laboratory of Education Ministry on Carbon Fiber and Functional Polymer, Beijing University of Chemical Technology, Beijing, 100029, China.
Nanoscale Res Lett. 2019 Mar 13;14(1):93. doi: 10.1186/s11671-019-2926-x.
Although it has been half a century since polyacrylonitrile (PAN)-based carbon fibers were first developed, the exact formation mechanism of skin-core structure of PAN-based carbon fibers, especially the stabilized PAN fibers, was still not well clarified from the viewpoint of the chemical structure. In order to address this aforementioned challenge, a powerful tool with nanoscale resolution named photo-induced force microscopy was applied to map the chemical group distribution in the cross section of stabilized PAN fibers and reveal the evolution mechanism of skin-core structure throughout the whole stabilization process. The results indicated that the formation of skin-core structure of stabilized PAN fiber was attributed to the complex and overlapped chemical reactions caused by gradient of oxygen along radial direction and the formation of dense crystal layer at the interface between the skin and core part. Finally, the crystal layer was destroyed and the monofilaments tended to be homogeneous with further oxidation.
尽管聚丙烯腈（PAN）基碳纤维首次被开发出来已有半个世纪，但从化学结构的角度来看，PAN基碳纤维，尤其是稳定化PAN纤维的皮芯结构的确切形成机制仍未得到很好的阐明。为了应对上述挑战，一种具有纳米级分辨率的强大工具——光诱导力显微镜被应用于绘制稳定化PAN纤维横截面中的化学基团分布，并揭示整个稳定化过程中皮芯结构的演变机制。结果表明，稳定化PAN纤维皮芯结构的形成归因于沿径向的氧梯度引起的复杂且重叠的化学反应，以及在皮层和芯层之间的界面处形成致密的晶体层。最后，随着进一步氧化，晶体层被破坏，单丝趋于均匀。
