聚丙烯腈基炭纤维对比分析:(一)微观结构

A comparative analysis of polyacrylonitrile-based carbon fibers:(Ⅰ) Microstructures

利用X射线广角衍射/小角散射、Raman光谱及高分辨透射显微镜对不同型号聚丙烯腈基炭纤维的晶态结构、孔结构、径向结构不均匀性、石墨化度、内部残余应力、结构取向性及分形现象进行了对比分析。结果表明,MJ炭纤维的微晶结构比T系列提升明显,内部残余应力逐步释放,结构取向性显著提升,石墨化程度也显著增强;但其微孔尺寸有所增大,径向结构不均匀性增加,体现了石墨化过程对炭纤维微观结构的显著影响。

X-ray wide angle diffraction/small angle scattering,Raman spectroscopy and high resolution transmission electron microscopy were used to characterize the crystalline structure,pore structure,radial structural heterogeneity,degree of graphitization,internal residual stress,crystalline orientation and fractal phenomena of various grades(T and MJ)of polyacrylonitrile-based carbon fibers made by Toray Inc,Japan.Results showed that compared with the T series fibers,the MJ series fibers had a significantly lower internal residual stress,better structural orientation and a much higher degree of graphitization,but the dimensions of the microvoids and the radial inhomogeneity were increased,which revealed the significant influence of graphitization conditions in making MJ series fibers on the microstructures of carbon fibers.