聚丙烯腈基炭纤维的扫描隧道显微镜研究

STUDY BY SCANNING TUNELING MICROSCOPE ON POLYACRYLINITRILE BASED CARBON FIBERS

用扫描隧道显微镜（STM）研究聚丙烯腈（PAN）基炭纤维的表面结构以及经过电化学腐蚀、拉伸试验和高温处理后的表面变化．未处理的纤维表面由沿纤维轴向排列的宽度不等的带状细纤维组成.随着放大倍数增加，表面显得粗糙，细纤维上分布着许多小晶粒．另外，还发现了构成炭纤维的细纤维呈螺旋结构环绕，沿轴向伸长．经电化学腐蚀后，纤维内部仍存在螺旋结构经过拉伸的炭纤维，在其临近断裂的区域里，观察到了扩展的孔洞及周围不均匀区．

Scanning tunneling microscope (STM) was used to characterise the surface topography of Polyacrylonitrile (PAN) based carbon fibers beforc and after electrochemical treatment, stretch resistance test and high temperature-treatment. A new kind of structure, the spiral structure was found not only on the sur-face but also in the inner layer. This kind spiral structure was caused by spinning process. The structure of fi-bers contained the shape of the precursor. There were some large cracks in the carbon fibers after stretching resistance test. The large cracks would result in carbon fibers breaking under certain stress condition. The dif ference in carbon fibers before and after the high temperaturc-treatment was compared- The change of the crystalline grains was also analysed.