MJ系列碳纤维微观结构的剖析

Analysis on the microstructure of MJ series carbon fibers

利用SEM、XRD和Raman光谱研究了高强高模PAN基碳纤维M40J、M55J、M60J的表面形貌和微观结构参数。结果表明:3种纤维的表面均存在沟槽,说明其原丝可能均为湿法纺丝。但沟槽的深度与均匀性又有所不同。XRD结果显示:M40J的石墨化程度最低,M55J次之,M60J最高。Raman光谱数据显示,M40J的RS、RC、RSC值均相对较大,M55J次之,M60J最小。说明M60J的表面和内部的石墨化程度均较高,但皮芯结构也最严重,这可能是导致其抗拉强度较低的原因之一。

The microstructure of high strength and high modulus PAN-based carbon fibers M40J, M55J, M60J were studied by scanning electron microscopy （SEM）, X-ray diffraction （XRD） and Raman spectroscopy. SEM results showed that the ridges and grooves were much more prominent in the three kinds of carbon fibers, indicating their precur- sors might be wet spirming. There were also some difference between them about their surface grooves depth and uniformi- ty. The grooves of M40J surface were lower and ununiform, while the grooves of M60J surface were deep and uniform. XRD results showed that M40J carbon fiber had the largest apparent crystallite layers spacing（d002） and porosity rate（Vp）, the smallest apparent crystallite size （Lc, La） and preferred orientation （g） in the three kinds of carbon fibers, while M60J carbon fiber was quitely contrary. Raman results showed that the Rs, Rc, Rsc of M40J were respectively determined to be 0. 998, 1. 322, 0. 745, while these of M60J were 0. 450, 0. 946, 0. 476 severally. It implied that M60J had the highest graphitazation degree in the surface and core, and the most severe skin-core structure, which accounted for the lowest ten- sile strength of M60J fiber.