Reactive Layer Assembly Sustains an Interlocked Structure in Green Processed and Scalable High-Performance Layered Wood
E. I. Akpan, K. Friedrich, Stefan Jacob, Eckhard Thines, Bernd Wetzel
Abstract
Wood can be processed into structural materials by partial removal of lignin and subsequent hot compression. The fundamental challenge of this process is achieving a cost-effective, green, and scalable production without compromising on performance. This article reports a green and scalable alternative method for producing high-performance wood-based materials. Thin wood veneers are pretreated in water at 160 °C to increase porosity and alter the structure, rendering it susceptible to subsequent delignification accomplished with dilute alkaline hydrogen peroxide solution. The modified veneers are assembled in layers by reactive functional bonding with an environmentally friendly resin (3 wt %). Densification is achieved in 4 h at 40 °C and the layer binding is activated at 150 °C for 15 min. The total process is limited to 6 h with the engineered layered wood showing specific strength and modulus (425 ± 29 MPa cm3 g–1 and 41 ± 3 GPa cm3 g–1) exceeding most high-performing structural materials. The layered wood exhibits over 14 times improvement in UV weathering behavior and 40 °C increase in thermal stability over natural wood, making it a low-cost, high-performance, lightweight alternative material for structural and semi-structural applications. Using a functional water-based binder, moisture-triggered formability in the wet state is assured and the need for external hydrophobic coatings to keep the interlocked state is eliminated.