The effect of recycling on the mechanical response of carbon fibres and their composites

The development of processes for recycling carbon–fibre composite waste rises a question yet to be answered: how good can the performance of recycled composites be? This paper analyses fibres reclaimed in commercial facilities, and compares the performance of subsequently manufactured recycled woven composites to that of the virgin precursor (with the same fibre architecture). Different pyrolysis cycles resulted into different compromises between complete resin removal and full fibre strength retention. At the composite level, this paper shows how strength varies with the reclamation cycle, re-impregnation process and loading direction, while stiffness remains virtually unaffected. It is shown that composite tensile strength is favoured by gentle pyrolysis cycles generating little fibre damage, while compressive strength is fully retained after more aggressive cycles which completely remove the matrix. This work proves that the mechanical response of recycled composites can rival that of virgin precursors, while highlighting the benefits of application-driven optimisation of reclamation processes.