Nacre-inspired gradient design and multifunctional wood-based composites using recycled GFRP from decommissioned wind turbine blades

Abstract

Traditional wood-based composites (WBC), typically composed of wood and polymer precursors, often exhibit limited stability and performance in diverse application scenarios, leading to material failure. Although novel multifunctional WBCs with enhanced strength, stability, ease of processing, and cost-effectiveness have been developed, challenges remain due to the high costs of functional additives and the complexity of interface engineering. This study proposes a gradient-distributed WBC reinforced with glass fiber-reinforced polymers (GFRP) derived from recycled decommissioned wind turbine blades (WTBs). Inspired by the natural layered structure of the nacre, we optimize the distribution of GFRP with varying mesh sizes across individual layers. The results demonstrate that WBC@GFRP composites show significant improvements in mechanical properties, with a 49% increase in modulus of rupture (MOR), 49% in modulus of elasticity (MOE), and 64% in internal bonding (IB) strength compared to pristine WBCs. Additionally, the composites exhibit enhanced dimensional stability, decay resistance, and flame retardancy, with a limiting oxygen index (LOI) of 30.1% and a 23% reduction in the average adequate heat of combustion. Accelerated weathering tests confirm the exceptional stability of the nacre-inspired structure under fluctuating environmental conditions, including water exposure, high humidity, and extreme temperature variations. This enhanced resilience is attributed to the gradient-distributed structure, which mitigates substrate deformation, prevents moisture penetration, and maintains mechanical integrity. These findings highlight the potential of WBC@GFRP for long-term performance in challenging applications, particularly in construction, packaging, and furniture industries, and present a novel approach for recycling WTBs and developing high-performance composites.