Determination of Carbon Fibre Structure by Electron Spin Resonance

Abstract

THE structure and properties of carbon fibres are currently receiving considerable attention. As part of a fundamental study of the processes of carbonization and graphitization of these fibres we are at present examining the electron spin resonance (ESR) characteristics of these materials. The use of this technique in studies of amorphous carbons and graphites is well known¹; however, ESR seems to have been little applied specifically to carbon fibres. The structure of these fibres was the subject of two recent communications^2,3 in which the results of studies using electron microscopy and electron and X-ray diffraction techniques were presented. These reports generally substantiated Shindo's classic studies⁴ of the carbonization of polyacrylonitrile (PAN) fibres indicating that the polynuclear aromatic planar fragments became strongly orientated with their planes parallel to the fibre axis. In this communication we report some results of an ESR study of the structure of these materials.