Carbon fibre fluorination: Surface and structural properties

Knowing that carbon fibre reinforced polymers are sensitive to moisture through their interphases, carbon fibres sized with Bisphenol A diglycidyl ether were fluorinated under a N-2/F-2 atmosphere, which confers them a hy-drophobic behaviour, as highlighted by wettability measurements. Low fluorination temperatures (< 23 degrees C) lead to a sizing perfluorination and even overfluorination without carbon fibre fluorination, while higher tempera-tures (> 25 degrees C) result in a carbon lattice fluorination with a complete desizing of the fibre through decompo-sition, that has been evidenced through X-Ray Diffraction and Raman spectroscopy studies. For both fluorination mechanisms, F-19 Nuclear Magnetic Resonance, X-Ray Photoelectron and infrared spectroscopies have been used to study the nature of fluorine bonds. Scanning Electron Microscope and Energy-Dispersive X-Ray Spectroscopy have evidenced a core-shell structure for the fluorinated fibres with a fibre degradation at the highest tem-peratures, also highlighted by tensile tests, Atomic Force Microscopy and Electron Paramagnetic Resonance.