The influence of non-catalysed steam explosion on lignocellulosic materials: A review to produce self-adhesive boards

Although research since 1980 has provided insight into the steam explosion process to exploit wood as a self-adhesive furnish in boards, a deeper understanding of the relationships between process parameters and the resulting self-bonding mechanisms remains essential. This review analyses the influence of non-catalysed SE pre-treatment on the performance of lignocellulosic materials used for the manufacture of binderless particleboards. The study focuses on three key operational parameters ‒ initial moisture content, particle size, and severity factor ‒ and their combined effect on the physical, mechanical, and environmental performance of the resulting boards. The analysis integrates findings from recent studies that employ SE as a green pre-treatment to promote lignin plasticisation, hemicellulose solubilisation, and lignin–polysaccharide cross-linking, thereby enhancing internal bond (IB) strength, modulus of rupture (MOR), and dimensional stability without the use of synthetic adhesives. Particular attention is also given to process-related emissions, including volatile organic compound emissions and carbon dioxide (CO₂), as well as to the rinsing of steam-exploded substrates as a factor influencing fibre chemistry and environmental performance. Overall, this review provides an updated synthesis of experimental evidence from 1980 to 2025 and identifies optimal pre-treatment conditions ‒ such as moderate severity (log R₀ = 3.5–4.0) and intermediate particle size (<2 mm) ‒ that enhance fibre cohesion and board quality. The work highlights promising research avenues for developing fully lignocellulosic, adhesive-free materials as sustainable alternatives in the wood-based panel industry.