The influence of micromechanical properties and reinforcement architecture on the mechanical response of recycled composites

Technologies for recycling carbon–fibre composites are now becoming mature, so a key challenge is to establish applications for the recycled products. This paper aims to further our understanding on the mechanical response of recycled composites, so as to guide the optimisation of recycling processes and support their use in non-critical structural components. This work thoroughly characterises three recycled composites and analyses the relations between fibre and interfacial properties, reinforcement architecture, and macroscopic mechanical response. An unequivocal relationship between the architecture of a recycled composite and its fracture toughness is established; this proves that fibre bundles are not necessarily a recycling defect, but can actually toughen the material by at least up to an order of magnitude without significantly reducing stiffness or strength.