Zhou Yiran, Sha Yang, Liu Wei, Gao Teng, Yao Zhuwei, Zhang Yaxin, Cao Weiyu
The Key Laboratory of Education Ministry on Carbon Fibre and Functional Polymer, Beijing University of Chemical Technology Beijing 100029 China
Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Materials, AECC Beijing Institute of Aeronautical Materials Beijing 100095 China.
RSC Adv. 2019 May 31;9(30):17051-17056. doi: 10.1039/c9ra02125f. eCollection 2019 May 29.
Electron probe micro-analysis (EPMA), micro-beam wide angle X-ray diffraction (Micro-beam WAXD), micro-Raman and nano-infrared (nano-IR) spectroscopy were performed to characterize the hierarchical radial structure within polyacrylonitrile (PAN) fibre which was obtained by the wet-spinning method, including morphology, aggregation structure and molecular chain conformation. The results indicated that along the radial direction of the PAN fibre, the skin layer reflects denser morphology compared to the core region. The crystallinity, -spacing of the (100) Miller plane and crystalline orientation in PAN fibres were gradually decreased from the skin layer to the central part, while the crystalline size shows opposite distribution tendency which was affected by the diffusion depending on the coagulation environment. As to the molecular chain structure, PAN chains tend to keep the helical conformation rather than planar zigzag conformation and packed more orderly in the skin layer of fibres.
采用电子探针微分析（EPMA）、微束广角X射线衍射（微束WAXD）、显微拉曼光谱和纳米红外（nano-IR）光谱对通过湿法纺丝制备的聚丙烯腈（PAN）纤维内部的分级径向结构进行表征，包括形态、聚集结构和分子链构象。结果表明，沿PAN纤维的径向方向，皮层比芯区呈现出更致密的形态。PAN纤维的结晶度、（100）密勒面的面间距和结晶取向从皮层到中心部分逐渐降低，而晶体尺寸呈现相反的分布趋势，这取决于凝固环境下的扩散作用。至于分子链结构，PAN链倾向于保持螺旋构象而非平面锯齿构象，并且在纤维皮层中排列更为有序。
