Carbon fiber recovery using water and benzyl alcohol in subcritical and supercritical conditions for chemical recycling of thermoset composite materials

Recovery of carbon fibers by recycling thermoset composites is highly desirable from both economic and environmental perspectives. This reduces waste disposal of scrap from production parts and end-of-life products. In this study, benzyl alcohol and water in subcritical and supercritical conditions were used to recover carbon fibers from composite materials for potential reuse in high-performance components. The reaction temperature and time duration were the experimental parameters. The methods were evaluated by measurement of the decomposition rate of epoxy resin, which reached up to 89.1 and 93.7 % with supercritical water and subcritical benzyl alcohol, respectively. The samples were characterized by scanning electron microscopy (SEM). SEM analysis showed complete separation of the composites as indicated by the clean recovered carbon fibers.