聚丙烯腈基炭纤维制备过程中的表面形态和结构研究  

Changes in the surface morphology and microstructure in the preparation of PAN-based carbon fibers

作　　者：王延相[1] 王成国[1] 朱波[1] 何东新[1] 井敏[1] 王强[1] 

机构地区：[1]山东大学材料科学与工程学院,山东济南250061

出　　处：《新型炭材料》2005年第1期51-57,共7页New Carbon Materials

基　　金：国家十五期间 863项目(2002AA304130);国家自然科学基金(59783002)~~

摘　　要：为了制备高性能的聚丙烯腈基炭纤维,用SEM和TEM等分析方法跟踪炭纤维生产全过程中纤维微观结构所发生的变化。在湿法纺丝中,控制预牵伸倍数为 7倍,调整凝固浴的温度为 16℃时,可纺出截面近似圆形的高质量原丝,纤维的截面和表面的微纤比较紧凑,表面缺陷和裂纹较少;原丝经过预氧化后仍保持原来的微原纤结构,纤维外部表层的石墨微晶较大,所含孔隙较少,内部的微晶较小且含有大量孔隙。用高锰酸钾改性原丝能够得到质量优异的预氧化纤维,改性预氧丝的纤维基面增加比未改性的多,基面沿纤维轴排列的程度更高。所制备的炭纤维具有由原丝演变来的微观结构,微纤沿纤维轴高度取向,微纤之间有细长的孔隙,并堆砌在一起形成枝化微纤的伸展网络,炭纤维截面形状也近似为圆形。合理调整制备工艺,得到了强度为 3.6GPa^4.2GPa,断裂延伸率为 1.6%~1.8%,模量为 235GPa^240GPa的聚丙烯腈基炭纤维。结果表明:炭纤维的微观组织结构与原丝的微观组织结构密切相关,高强度、高取向度和结构均匀的原丝是获得高强度和高模量炭纤维的前提。To obtain high performance PAN-based carbon fibers, the microstructural changes of the fibers were systematically tracked by SEM and TEM in the process of wet-spinning, preoxidation, precarbonization, and carbonization. High-quality PAN fibers with a near circular cross-section, compact microfibrils and few defects or fissures on the surface are obtained by wet spinning at a coagulation temperature of 16 degrees C and a pre-stretching ratio of 7. The microfibrils on the surface of the PAN fibers are retained after oxidative stabilization. The graphite crystallites in the outer layer of the carbon fibers are large with few pores, while the inner crystallites are small with many pores. High quality oxidative stabilized PAN fibers can be obtained by treating the precursors with potassium permanganate solution, which suggests that it can increase the number of basal planes as A ell as the degree alignment along the fiber axis. The carbon fibers inherit the microstructure of the PAN fibers, and the degree of alignment of the microfibrous graphite crystallites along the fiber axis is high, leading to the formation of fine and long pores and regularly extended networks viewed from the cross-section. At appropriate carbonization conditions, carbon fibers having tensile strength of 3.6 - 4.2 GPa, elongation at break of 1.6 - 1.8%and moduli of 235 - 240 GPa are obtained. High performance carbon fibers can be obtained from PAN fibers With high tenacity, high degree of preferred alignment, and few defects inside and on surface of the fibers.

关 键 词：聚丙烯腈原丝 预氧化 炭化过程 扫描电子显微镜 透射电子显微镜 炭纤维 制备方法 预氧化工艺 

分 类 号：TQ342.742[化学工程—化纤工业]