Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), School of Material Science and Engineering, Shandong University, Jinan, China.
School of Material Science and Engineering, Shandong Jianzhu University, Jinan, China.
Microsc Res Tech. 2019 Dec;82(12):2026-2034. doi: 10.1002/jemt.23372. Epub 2019 Sep 5.
The microfibrils served as the structural elements in polyacrylonitrile (PAN) fiber, which played an important role in the quality of the PAN precursor fibers. Their morphologies were examined by the scanning electron microscopy (SEM), atomic force microscopy (AFM) and high-resolution transmission electron microscope (HRTEM). The microfibrils existed in all of PAN fibers and arranged evenly in the cross-sections. Furthermore, the pores existed between the microfibrils. The unoriented microfibrillar network was already formed in nascent fiber during coagulated process. Although the microfibrillar network was elongated and the microfibrils oriented along the fiber longitudinal direction during the spinning process, the interconnected microfibrillar network was still existed in the fiber transverse section. Furthermore, the transverse connection of the microfibrils was reinforced and the small microfibrils were tended to aggregate into the large fibrils. For mechanical performance of PAN fibers, their tensile strength increased to 708 MPa and the elongation at break decreased to 15.5%. PAN fibers exhibited ductile rupture during the mechanical test and the microfibrils served as reinforcing elements.
微纤维作为聚丙烯腈（PAN）纤维的结构元件，对 PAN 原丝纤维的质量起着重要作用。通过扫描电子显微镜（SEM）、原子力显微镜（AFM）和高分辨率透射电子显微镜（HRTEM）对其形态进行了研究。微纤维存在于所有的 PAN 纤维中，并在横截面中均匀排列。此外，微纤维之间存在孔隙。在凝固过程中初生纤维中已经形成了无定形的微纤维网络。尽管在纺丝过程中微纤维网络被拉长并且微纤维沿纤维纵向取向，但纤维横截面上仍存在相互连接的微纤维网络。此外，微纤维的横向连接得到了加强，小的微纤维趋于聚集成长纤维。对于 PAN 纤维的力学性能，其拉伸强度增加到 708 MPa，断裂伸长率降低到 15.5%。在力学测试中，PAN 纤维表现出韧性断裂，微纤维作为增强相。
