Processing Waste Lignocellulose Biomass into Eco-Friendly Structural Material Via a Scalable Binder-Free Lamination

To achieve the goal of carbon neutrality, it is great significance to develop the high-performance and sustainable structural material. In this work, an eco-friendly, high-strength, super-hydrophobic, and thermally stable structural material based on low-value waste biomass (e.g., wood residues, crop straw and waste paperboard) was fabricated through a scalable binder-free lamination process. The waste biomass was first separated into cellulosic fibers by the simple pulping technology, which were further molded into mat and laminated into structural material without commercial adhesives. The moisture content in mat was used for regulating fiber plasticity during lamination process. In virtue of the water-induced cell wall plasticization, the laminated material showed high internal bonding strength of 2.24 MPa (e.g., 0.7 MPa required for plywood) and excellent flexural strength of 134.81 MPa (e.g., 83.13 MPa for wooden composites). Benefitting to the silica modification, the laminated materials exhibited a super-hydrophobic surface with the water contact angle as high as 154.1°, and superior mechanical stability with 94.3% flexural strength remained even after two months of ultraviolet radiation, which were much better than those of commonly used polypropylene and wooden composites. The finite element model demonstrated the mechanically enhanced laminated materials possess stress delamination advantages, favoring to the buffering improvement. Moreover, the dynamic mechanical analysis revealed that the glass transition temperature was reduced after water swelling fiber cell wall. This work provides a new strategy to develop co-friendly structural materials with high strength, super-hydrophobic and thermally stable performance having huge potential in furniture applications.