Abstract

Carbon fibre reinforced composites (CFRP) are key in different industrial sectors as they combine lightness and robustness. This circumstance and the growing need to take advantage of the resources of any product, has triggered a strong demand to establish sustainable technological solutions that allow the effective use of composite materials: resins (matrix) and fibres (reinforcement).

Limited to mechanical recycling, recycling alternatives for CFRP with thermosetting resins have focused on thermochemical treatments, usually pyrolysis to recover the fibres, degrading the matrix. In addition to thermal routes, solvent treatments under supercritical conditions have also been studied. However, these processes exclude resin recovery and involve a partial loss of mechanical properties of the fibres due to the heat treatment (450-550 °C).

As an alternative, a solvolysis using mild conditions is proposed to treat CFRPs with amine-hardened epoxy resins, so that the fibres are recovered with all their properties and the organic matrix is materially valorised. This process is applied to reference materials of known composition and validated with real residues with good results in terms of degree of resin decomposition. The recovered fibres show almost resin-free surface and seem to have mechanical properties comparable to those of virgin fibres.