聚丙烯腈预氧化纤维组织结构的遗传与演变研究

Research on Microstructural Evolution of Polyacrylonitrile Fibers during the Pre-oxidative Stabilization Process

采用扫描电镜(SEM)和透射电镜(TEM)仪器和方法,对聚丙烯腈(PAN)原丝和不同温度阶段预氧丝的表面形貌、断面形貌和内部组织结构进行了系统的分析。结果表明,PAN原丝的原纤结构在整个预氧化过程中是具有遗传性的,随着预氧化的不断进行,原纤的韧性逐渐降低,原纤之间的结合更为紧密;预氧化反应由纤维外部向芯部逐步进行,形成了组织致密、脆性高的皮层和组织疏松、韧性高的芯部。皮层区域的晶粒尺寸细小,分布均匀,无择优取向,非晶组织较为致密;而芯部区域的组织粗大,呈现出沿纤维轴向排列的层片状结构,越靠近芯部,层片的取向越明显。

The surface morphologies,cross-sectional fractrure morphologies and inner microstructure of polyacrylonitrile（PAN） precursor fibers and oxidative stabilized fibers at different temperature stages were systematically analyzed by scanning electron microscope（SEM） and transmission electron microscope（TEM）.The results show that the oxidative stabilized fibers have the same fibril structures with PAN fibers.The fibrils toughness gradually decreases and the bond becomes stronger during the process.Oxidative stabilization reactions develop from the outside of fibers to inner part,as a result,a kind of skin-core structure forms.The skin region has compact microstructure and higher brittleness,while the inner region has loose microstructure and higher toughness.The crystallites are fine and even distributed without orientation in the skin region;The microstructure in the core region is coarse with the lamellas arranging along fiber axis.The closer to core region,the more obvious orientation of lamellas.