Development of Oriented Strand Boards Using Leftovers of Veneer-Wood and Non-formaldehyde Lignin or Tannin Adhesive Formulations

The urgent need for sustainable construction materials has catalyzed research into formaldehyde-free adhesives for wood composites and the effective valorization of industrial wood residues. This study addresses the growing demand for sustainable alternatives to formaldehyde-based adhesives in the wood composites industry. The present research focuses on developing oriented strand board (OSB) panels using veneer-wood leftovers bonded with two formaldehyde-free adhesives: phenol-lignin-glyoxal (PLG) and phenol-tannin-glyoxal (PTG) resins. The adhesive formulations were developed with a focus on environmental compatibility, mechanical strength, and moisture resistance, following procedures and compositions previously reported in scientific literature. Thus, while the adhesive systems themselves are not novel, their application in the valorization of wood veneer residues for OSB manufacturing represents a significant advancement. Furthermore, this study presents an innovative approach to mitigate these challenges by repurposing veneer-wood leftovers-a byproduct constituting approximately 20% of plywood manufacturing-as a sustainable feedstock for OSB panels, thereby reducing dependence on raw timber. OSB panels were fabricated through a hot-pressing process and evaluated for physical and mechanical performance, including density, modulus of rupture (MOR), water absorption, and thickness swelling over time. The OSB/PLG panels demonstrated superior mechanical strength, while OSB/PTG panels showed enhanced water resistance, highlighting the distinct advantages of each formulation. Notably, OSB manufacturing typically relies on juvenile hardwoods, raising concerns over deforestation and short-rotation forestry. In contrast, utilizing veneer-wood waste as feedstock offers an environmentally beneficial route to reduce raw wood consumption and promote circular resource use. This research contributes to the advancement of bio-based adhesives for engineered wood products by validating the performance of glyoxal-crosslinked lignin and tannin systems in OSB applications. The findings support the industrial feasibility of replacing conventional synthetic resins with renewable alternatives, aligning with environmental regulations and sustainability goals.