Alignment of recycled carbon fibre and its application as a reinforcement

A fluidised bed process has been developed for recycling carbon fibre from scrap polymer composites. The recycled carbon fibre is clean and no further surface treatment is needed for it to be suitable for reuse in polymer composites. The recycled carbon fibre is recovered as short, individual filaments in a fluffy form with fibre lengths typically between 5 and 20mm. In this work, a hydrodynamic alignment method was assessed to process the fluffy form of the recycled carbon fibre into a high performance aligned mat. The alignment of the fibre was characterised by manufacturing the aligned mat into epoxy resin composite. Optical microscopy of the cross-section of the composite and the ratio of the mechanical properties along and transverse the fibre direction indicate a good degree of fibre alignment. It was found that shorter fibres, 5mm in length, can be aligned more easily than longer fibres of 20mm length. The research shows that carbon fibres, produced as fluffy, short filaments in their recycled form, can be upgraded to produce an aligned product suitable for higher grade applications.