Towards green carbon fibre manufacturing from waste cotton: a microstructural and physical property investigation

Abstract

The work presents the usefulness of cotton fibre waste as a source of carbon fibre (CF) by pyrolysis. Different pyrolysis temperatures were studied to assess the surface and structural changes during carbonisation. The structural and surface modification of fibres during carbonisation was studied by thermogravimetric analysis (TGA), Field Emission Scanning Electron Microscopy (FESEM), and Raman spectroscopy. Low-pressure plasma employed for surface functionalization treatment in presence of oxygen was conducted. The surface modification was analysed and compared by X-ray Photoelectron Spectroscopy (XPS) and contact angle analysis. Carbon fibre structural strength was studied using nanoindentation. The carbon fibres before and after functionalization revealed a significant change in surface hydrophilicity. In nanoindentation, the maximum displacement of carbon fibre produced at 400 °C is higher when compared to treatment of 600 °C and 800 °C, for identical applied load, revealing lower resistance to applied load, while the carbon fibre produced at 600 °C has the least displacement, i.e. higher resistance to applied load. Enhancement of material strength (through resistance to applied load) after surface functionalization is evidenced for the case of carbon fibre produced at 400 °C and no effect for carbon fibre (both plain and functionalized) produced at 800 °C.

Keywords

• waste cotton
• carbon fibres
• nanoindentation
• surface tension
• pyrolysis