Using higher rates of stabilization of a wet-spun pan fibre to understand the effect of microstructure on the tensile and compressive properties of carbon fibre

The transformation of a polyacrylonitrile (PAN) precursor fibre into carbon fibre using varying stabilization times during carbon fibre manufacture is presented in this work. The wet-spun precursor fibre is a specifically designed PAN co-polymer made up of acrylonitrile, methyl acrylate and 3 wt% itaconic acid. The residence or stabilization times in the oxidation ovens are varied from 32, 64 and 96 min, enabling investigation of the impact upon microstructure upon tensile and compressive properties. Using a continuous pilot scale carbonization line for faster cyclization and dehydrogenation, the precursor fibres exhibited lower oxygen uptake contributing to the formation of a less dense and more amorphous carbon fibre. Synchrotron based SAXS-WAXS characterisation and Raman spectroscopy of the carbon fibre microstructure displays lower orientation and crystallinity, with higher void concentration. This led to lower electrical conductivity, lower tensile strength (19 %) but higher compressive strength (27 %) when reducing stabilisation times from 96 to 32 min.