Effect of Post Spinning Modification on the PAN Precursors and Resulting Carbon Fibres

The impregnation of a special grade polyacrylonitrile （PAN） precursor fibres was carried out in a 8 wt. % KMnO4 aqueous solution to obtain modified PAN precursor fibres. The foctts is primarily on the effects of modification on the chemical structure and the physical mechanical properties of precursor ribres, them-aft stabilised and their resulting carbon fibres, which were characterized by the con-bination use of densities, wide-angle X-my diffraction （WAXD）, X-my photoelectron spectrosopy （XPS）, Elemental analysis （EA）, Fourier transform infrared （FT-IR） and scanning clectronmicroscope （SEM）, etc. KMnO4 as a strong oxidizer can swell, oxidize and corrode the skin of a precursor fibre, tin, form partly C≡N groups to C=N ones, decrcase the crystal size, increase the orientation index, increase the crystallinity index, furthermore increase the densities of modified PAN precursors and resulting thermal stabiliscd fibres. As a result, the carbonfibres developed from modified PAN fibres show an improvement in tensile strength of 31.25% and an improvement in elongation of 77.78%, but a decrease of 16.52% in Young＇s modulus.