Recovery and reuse of carbon fibre and acrylic resin from thermoplastic composites used in marine application

Abstract : The development of new sustainable routes towards better environmental footprint of composites for marine boatbuilding is motivated by the absence of eco-friendly and economically viable recycling techniques to deal with growing end-of-life thermoset boats waste and increasing restrictive legislation. Thermoplastic composites may offer the possibility to recover raw materials from retired parts, which could have a substantial environmental and economic benefit. This study investigates the feasibility of recovery and reuse of both reinforcement and matrix from a carbon fibre reinforced thermoplastic Elium composite. An original pyrolysis process allowed the depolymerisation of the acrylic matrix and recovery of clean carbon fibres and matrix monomer. Distillation was used to purify the monomer from impurities and a recycled Elium resin was synthesized and reused as matrix with long and aligned recycled carbon fibre reinforcement. The study of the morphological and composition differences at fibre scale resulted in concluding that sizing has been decomposed during depolymerisation process and only small traces of polymer were left on fibre surface. Virgin and recycled resin reinforced with carbon fibre laminates were produced by resin infusion. While tensile modulus, strength and strain at break were nearly unchanged, interlaminar shear strength results showed enhanced fibre-matrix interphase bonding. Dynamic mechanical analysis confirmed the good quality of recovered carbon fibres as well as similar virgin and re-polymerised resin properties. The new composite made from both recycled fibre and matrix could be used in the same application field.