Fossil-Free Fibreboard: Material Properties of an IonoSolv-Derived All-Wood Biocomposite

Fibreboard plays a central role in the global wood products industry, converting large volumes of residues into uniform, high-value panels. However, despite its reputation as a sustainable material, commercial fibreboards rely on petrochemical adhesives—such as urea- and phenol-formaldehyde resins—that emit volatile organic compounds and undermine the material’s green credentials. This study presents a fully bio-based, additive-free alternative to conventional fibreboard, manufactured using the ionoSolv process. In this one-pot route, lignin is extracted and chemically modified to act as a dry-form binder, then precipitated onto cellulose fibres and hot-pressed without any synthetic resin. This work systematically evaluates the resulting biocomposite’s mechanical, physical, and optical properties, and develops a predictive model linking production conditions to performance. The material achieves tensile strengths up to 30 MPa and Young’s moduli up to 14 GPa—matching or exceeding MDF in strength and all conventional fibreboards in stiffness—with densities similar to tempered hardboard. At less than 300 µm thick, the material blocks over 99.7% of UV radiation, and under backlighting displays vivid colour shifts from black or brown to orange, pink, or purple—depending on process conditions—unlocking interior design applications where both dynamic visual effects and mechanical performance are valued. The developed model allows users to tailor mechanical, physical, and optical properties for a given use case by tuning extraction and pressing conditions. These findings demonstrate that industrial wood residues can be transformed into structurally competent, optically dynamic fibreboard alternatives using a fossil-free process, advancing both material performance and sustainability in the engineered wood sector.