Optimisation of recycling process parameters of carbon fibre in epoxy matrix composites

In order to improve the mechanical properties of recycled carbon fibres, this article adopted the centre composite design method to conduct high-temperature pyrolysis recycling experiments on carbon fibre filaments. The experimental results revealed the influence of the residual resin content in the recycled carbon fibre bundles and the degree of fibre oxidation on the tensile properties. On the basis, the process parameters were further optimised for the high temperature pyrolysis recycling process of resin-matrix carbon fibre composites through multi-island genetic algorithm. The results suggest that (1) in the process of pyrolysis and oxidation, the temperature has the greatest influence on the properties of the fibres, and a small amount of resin residue helps improving the tensile strength of the recycled carbon fibres; (2) when the temperature is at a constant value in the range of 400–520 ℃, the pyrolysis time has a parabolic relationship with the tensile strength of recycled carbon fibres; (3) the tensile strength of the recycled carbon fibres reaches 80 % with 5.6 % resin residue remained in the recycled carbon fibre bundle after continuous pyrolysis at 428 °C for 4.0 h, and such a strength meets the mechanical performance requirements of recycled carbon fibre.