Laminated composites with an ultra-high cellulose content exhibit high strength and toughness

Wood-based laminated composites with excellent strength and toughness have attracted much attention, but it is a challenge to process fast-growing natural poplar wood with poor mechanical properties into high-performance laminated composites without the use of adhesives. In this study, natural poplar wood was delignified and TEMPO-oxidized by a “top-down” strategy to obtain a wood scaffold with a cellulose content of up to 98%, which was then used as a substrate and impregnated with Ca²⁺ and PVA to form a large number of hydrogen and ionic bonds within the wood. Finally, under the action of hot pressing, laminated composites with high tensile strength (237 MPa), flexural strength (246 MPa) and impact toughness (50.45 KJ/m²) were obtained, which also displayed excellent thermal stability and water resistance. This work demonstrates that the utilization of renewable fast-growing poplar wood as a substrate and glue-free bonding method can produce low-cost, sustainable and high-performance wood-based laminated composites.