Abstract: The configuration of the microvoids in polyacrylonitrile(PAN)-based carbon fibers was studied by multi-orientated one-dimensional small angle X-ray scattering. The microvoids show a preferred orientation and have needlelike shape elongating along the fiber axis,and the oriented angle is Φ=14°. the cross-section radius of the microvoids projected onto the fiber cross section is R=1.14 nm and the length projected onto the fiber axis is L=17.98 nm. The method developed in this paper reveals some aspects of the configuration of the microvoids which were only available with two-dimensional small angle X-ray scattering technique such as Φ and L,and can be applied to the characterization of the configuration of the microvoids or the microfibrils in other fiber systems.

Key words: Multi-orientated one-dimensional SAX, Carbon fiber, Microvoids