PAN Precursor Fibres Containing Multi-Walled Carbon Nanotubes

The spinning conditions of wet spun polyacrylonitrile (PAN) fibres containing multi-walled carbon nanotubes (MWCNTs) were investigated On the basis of images from a transmission electron microscope, it was shown that the MWCNTs are well dispersed in the fibre matrix as well as straightened and oriented in the direction of the fibre axis. The presence of MWCNTs in the fibre matter caused an increase in the crystallinity of the precursor fibres and a decrease in their porosity. The tenacity of the composite fibres was lower than that of pure PAN fibres, which was caused by the fact that carbon nanotubes hindered deformation in the drawing stages, resulting in a lower draw ratio possible to be obtained of composite fibres compared to standard fibres. For the PAN precursor fibres obtained a two stage carbonisation process was conducted: The first stage was conducted in an oxidative atmosphere (at 140 degrees C for 5 hours and then at 200 degrees C for 6 hours in air). The second stage was conducted in an inert atmosphere (at 1000 degrees C for 5 minutes in argon atmosphere). The strength of carbon fibres containing MWCNTs obtained shows, in the majority, no significant differences in comparision to reference fibres without MWCNTs. However the tensile strength was lower.