Recycling, remanufacturing and applications of semi-long and long carbon fibre from waste composites: A Review

Carbon fibres can be reclaimed and processed to different forms as feed material to make remanufactured carbon fibre composites. Use of semi-long (25-100 mm) and long (>100 mm) reclaimed carbon fibres in composites has the potential to enhance the overall mechanical performance of composites made from reclaimed carbon fibres. However, the present processes of recycling of carbon fibres lead to shortening of fibre length, surface degradation, alignment, which in turn, decrease the load bearing capacity and matrix bonding in the composites. To increase the structural performance and mechanical characteristics of reclaimed carbon fibres-based composites, possible pre-treatment methods to semi-long/long reclaimed carbon fibres should be explored. This paper presents a detailed review of various preparation and remanufacturing processes for semi-long/long reclaimed carbon fibres and evaluation of their performance and potential applications. It is found that among all the recycling methods, the Electrically driven Heterocatalytic Decomposition method can produce semi-long/long reclaimed carbon fibres with minimal damages. After reclaiming the carbon fibres, they must be opened and separated from the fluffy form for further processing; long staple carding is one of the mostly used methods for opening and producing randomly aligned mats and tapes. To enhance the performance of composites made from semi-long/long reclaimed carbon fibres, it is essential that fibres are aligned unidirectionally as much as possible. Friction spinning is found to be an efficient method to achieve high alignment of semi-long/long fibres. Furthermore, this paper advocates the use of advanced manufacturing techniques for fibre alignment and customization, which could result in improved repeatability, reduced variability, reduced material waste, and increased suitability for specific applications.