Advances in the circularity of end-of-life fibre-reinforced polymers by microwave intensification
Ignacio Julián, A. García-Jiménez, A. Aguado, C. Arenal, A. Calero, V. Campos, Gabriela Barrera Escobar, Ángel M. López-Buendía, D. Romero, Eva Verdejo, N. García-Polanco
Abstract
The growing use of fibre-reinforced polymer (FRP) composites and the increasing global generation of FRP waste implies an urgent need to develop a circular economy strategy to promote the recovery of fibres and the valorisation of resins. This review paper analyses the current scenario of FRP recycling technologies and evaluates the potentials of microwave-assisted heating as a technology to provide an intensification in terms of energy-efficiency, selective heating and processing speed, as well as an electrified thermal treatment for FRP recycling. The paper presents an overview of the estimated FRP production and waste generation per sector in the coming decennia and the current and envisioned international legislation related to the management of end-of-life FRP. The paper also discusses the strong and weak points of the existing FRP recycling technologies, their readiness level and overall environmental impact in terms of equivalent CO2 emissions. Furthermore, the emerging microwave-assisted FRP recycling technology is evaluated, showcasing the potentials and obstacles for its implementation and the potential end-use and characteristics of the recycled components. A literature survey on the existing prototypes, MW-assisted waste-to-value processes and reported energy demand is conducted. Finally, the required resources and framework for the consolidation of the MW-assisted FRP recycling as an alternative and economically viable technology are assessed.