RECYCLING METHODS FOR FIBERS IN CARBON FIBER REINFORCED POLYMERS

Thanks to their superior mechanical properties, Carbon Fiber Reinforced Polymers (CFRPs) are used as advanced materials in different sectors and their application has been extended from aerospace sector to automotive industry, sporting goods, renewable energy and construction. Therefore, the global demand of these type of material has seen an increase during the last years. Nevertheless, an increase of this production goes hand in hand with an increase of non-biodegradable waste (that are expected to be more than 263 ktons by 2030). Currently, unsatisfactory solutions are adopted for the disposal of these materials, since methods such as landfilling or incineration will lead to a serious environmental pollution. Unfortunately, to date, the literature does not present much content inherent to disposal of these type of materials, and the main technologies for the recovery of the fibers are not yet applied at the industrial level. Furthermore, also the production of carbon fibers lead to the pollution of the environment, since the carbon fibres manufacturing is an energy intensive process. Due to this, the recycling technique based on the reclamation of carbon fibers are continuously under innovative investigation. So, by means of this thesis, innovative and eco-friendly strategies for the disposal of CFRPs composite materials are defined and analysed in depth. These techniques are mechanical, thermal and chemical recycling. The first is based on crushing and milling the waste, while the other two on decomposing the waste by means of thermal (pyrolysis and fluidized bed) and chemical (solvolysis) processes. The properties and the composition of the recycled carbon fibers are discussed for each technique. While, at the end of the report, the most promising method is selected, discussing what can be recovered in energy terms and evaluating if the method can be self-sustainable or not.