Carbon fibres with ordered graphitic-like aggregate structures from a regenerated cellulose fibre precursor

Abstract

The production and characterisation of low modulus carbon fibres is reported from a commercially available regenerated cellulose fibre (CordenkaTM). The fibres were heat treated before the graphitisation at a temperature of 200 °C. Fibres were further heat treated and graphitised at a temperature of 2000 °C. Polarised Raman spectra of carbonised/graphitised fibres were recorded. The ratio of two Raman peaks located at ∼1350 cm-1 (D-band) and at ∼1600 cm-1 (2D band) – the ID/IG ratio – were used to follow the onset and development of the carbon/graphitic structure. It is shown that single carbon fibres processed at 2000 °C have a modulus of ∼70 GPa and strain at break >2%. A Raman spectroscopic method that follows the shift in the position of the 2D band suggests a modulus of ∼77 GPa. Transmission Electron Microscope imaging of the fibres reveals a sub-structure containing aggregates of oriented concentric turbostratic carbon domains, some of which are reminiscent of carbon nanotubes. These relatively high strength fibres (1.5 GPa) could be possible alternatives to E-glass fibres in low weight (∼30% lighter than E-glass), high volume automotive and marine applications. It is also shown that these fibres can be converted in a woven precursor form to a carbon fibre fabric without the need to weave brittle filaments.