University of
Oxford

Research Summary

Polyacrylonitrile (PAN) is the leading precursor in carbon fibre manufacturing because of its high carbon yield and mechanical strength. The performance of carbon fibres is directly determined by the properties of the PAN precursor fibres. However, current production methods do not fully exploit the theoretical mechanical potential of PAN.

Enhancing the mechanical performance of PAN fibres by incorporating graphene is promising, but commercial graphene typically exhibits low quality, with high defect densities and multiple layers (>10 layers), with dispersion being an additional challenge.

In Situ Graphene Synthesis in PAN Solutions

This study addresses these limitations by introducing a novel approach: incorporating in situ synthesised graphene into PAN precursor solutions, achieving a uniform dispersion of 0.21 mg/ml graphene with an average of nine layers. The key steps of the novel synthesis process are summarised in the schematic below:

Electrospinning of Graphene-Reinforced PAN Fibres

The precursor solution is then used to produce fibres via electrospinning on a drum collector, rotating at approximately 8000 rpm, corresponding to a linear velocity of ∼67 m/s. The schematic on the left illustrates the electrospinning process, while the right shows a high-speed drum collector I independently developed — teaching myself mechanical design and Fusion 360 to deliver a custom-built 8000 RPM prototype that outperformed commercial alternatives:

This process produces uniform, graphene-reinforced fibres with an average diameter of 228±45 nm, demonstrating a threefold improvement in stretchability over non-reinforced fibres. The left image shows the electrospun fibre mat, while the right image presents high-resolution scanning electron microscope (SEM) images and a diameter distribution plot, revealing the aligned structure and uniform thickness of the fibres: