Recycling Process of a Basalt Fiber-Epoxy Laminate by Solvolysis: Mechanical and Optical Tests

Basalt fibre epoxy composites well suit various engineering applications for their mechanical properties and chemical stability. However, after basalt/epoxy product lifespan, there are not many established ways to treat and recycle the fibers without deteriorating their physical, mechanical and chemical properties. In this study, a chemical recycling method for basalt fiber reinforced polymers is presented. The process is based on previous studies concerning carbon fibers epoxy composites in which the fibers are separated from the polymeric matrix through a solvolysis reaction at temperature below 160 °C. Firstly, the specimens are thermally pre-treated in a heater set over the glass transition temperature, to promote the polymeric swelling of the matrix. The chemical degradation is obtained by means of a solution of glacial acetic acid (AcOH) and hydrogen peroxide (H2O2): compact, clean, resin-free, recycled woven fabrics are obtained and the original length of the yarns is maintained. Breaking tenacity of the recycled basalt fibers is kept up to 90.5% compared to the virgin ones, while, with a pyrolysis treatment, this value cannot exceed the 35%.