Regenerating performance of glass fibre recycled from wind turbine blade

Abstract

The value of recycled glass fibres is reduced significantly due to loss in strength and surface functionality during recycling. This work investigates the potential of a variety of treatments to regenerate the strength and surface functionality of glass fibres recycled from retired wind turbine blades using an in-house developed fluidised bed process. It was found that soaking in hot NaOH solution could provide approximately a 130% increase in the tensile strength of recycled glass fibre; concluding that changes to surface morphology due to etching was the re-strengthening mechanism. The interfacial adhesion between recycled glass fibre and polypropylene was also examined. A significant reduction in interfacial shear strength was observed after recycling which is attributed to the loss of original sizing after recycling. Regenerating the interfacial shear strength between recycled glass fibre and polypropylene proved challenging with the use of aminopropyltriethoxysilane coupling agent alone, however, a twofold increase in the interfacial shear strength was attained by modifying the polypropylene matrix with maleic anhydride. It was found that NaOH and silane treatments restored the interfacial shear strength between interfacial shear strength and epoxy to that obtained with as received glass fibres. This work shows that substantial improvements in recycled glass fibre strength and fibre-polymer adhesion can be achieved after utilising various regeneration treatments, in turn producing recycled glass fibres with significantly enhanced reinforcement potential.