Chemical recycling of carbon fibre composites using alcohols under subcritical and supercritical conditions

• Published in: The Journal of supercritical fluids Vol. 46; no. 1; pp. 83 - 92
• Main Authors: Piñero-Hernanz, Raúl, García-Serna, Juan, Dodds, Christopher, Hyde, Jason, Poliakoff, Martyn, Cocero, María José, Kingman, Sam, Pickering, Stephen, Lester, Edward
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2008
• Subjects: Alcohol; Carbon fibre reinforced composites; Chemical recycling; Degradation; Elimination; Epoxy resin; Degradation; Epoxy resin; Alcohol; Chemical recycling; Carbon fibre reinforced composites; Elimination
• ISSN: 0896-8446; 1872-8162
• DOI: 10.1016/j.supflu.2008.02.008

Chemical recycling of carbon fibre reinforced composites (CFRCs) has been investigated using subcritical and supercritical alcohols as reactive-extraction media. The epoxy resin that joins the fibres is degraded during the process, producing fibres that retain 85–99% of the strength of the virgin fibres. Methanol, ethanol, 1-propanol and acetone were employed as solvent-reagents to conduct experiments in batch and semi-continuous-type reactors at temperatures ranged from 200 to 450 °C. The impact of flow rate and the addition of alkali catalysts (i.e. NaOH, KOH and CsOH from 0.016 to 0.50 M), was also investigated. Experiments performed in the semi-continuous flow system enhanced the mass transfer steps and reduced temperature requirements, thus eliminations of resin of 98 wt.% were achieved using at 350 °C and 1.1 kg-alcohol/kg-fibre/min and, at the same solvent flowrate at 275 °C using 0.02 mol/L of KOH 96.5 wt.% was obtained.