TEM study of some recent high modulus pan-based carbon fibers

Commercial Torayca high modulus PAN-based fibers were investigated by transmission electron microscopy, in relation to their tensile properties. It was found that, although it is often difficult to obtain quantitative parameters, tensile strength σ is mostly related to data pertaining to cross sections. However, not only the transverse but also the longitudinal radius of curvature of aromatic layers is to be taken into account, as already mentioned in previous papers. In addition, a high stacking order is also found favorable for reaching high σ values. The Young's modulus is mostly related to data issued from longitudinal sections: It increases as misorientations within a stack decrease, as the average nanopore length increases, and as La increases.