Wood Fibre Processing

Wood fibre processing transforms raw timber into materials and products through mechanical, chemical and thermo-chemical pathways. In the pulp and paper sector, wood chips undergo pulping—either by high-yield mechanical refining or by chemical delignification—to liberate cellulose fibres while separating lignin and hemicellulose. Mechanical pulping yields nearly all the wood mass but consumes large amounts of energy and produces fibres with high opacity and moderate strength. Chemical pulping (notably the kraft process) employs caustic soda and sulphide at elevated temperature to remove lignin, delivering strong, flexible, hydrophilic fibres for paper, board and dissolving grades. Subsequent bleaching and refining tailor brightness, purity and fibre fibrillation. Beyond pulping, wood‐fibre streams feed composite panels and densified timbers: engineered products exploit fibre–matrix interactions to achieve enhanced stiffness, damage tolerance and moisture resistance. Meanwhile, wood-based adhesives have evolved from petrol-derived resins to bio-derived and non-isocyanate systems, leveraging lignin, tannin, proteins and polysaccharides to bond veneers, particleboards and structural composites with reduced VOC emissions and improved recyclability. Emerging technologies in hydrothermal densification, microfibrillation and nanoparticle reinforcement further expand the functional palette of wood‐fibre materials, underpinning applications in construction, packaging, energy and beyond.

Research from Nature Portfolio

Recent studies have demonstrated that uncondensed lignins isolated directly from lignocellulosic biomass can serve as waterborne adhesives for plywood. By suspending these lignins in water and applying conventional hot-pressing, panels match the mechanical performance of formaldehyde-based resins across a broad temperature range. Mechanistic work indicates that water plasticises the lignin, enabling vessel infiltration and in situ crosslinking with cell-wall phenolics to yield robust interfacial adhesion. In a parallel advance, fast-growing bamboo has been transformed into high-performance structural composites via delignification, in situ growth of titanium dioxide nanoparticles and hot pressing. The resulting densified bamboo exhibits double the flexural strength and stiffness of native culms, while acoustic-emission analysis reveals that nanoscale TiO2 induces microfibrillation and energy-dissipating fracture mechanisms, substantially raising toughness and damage tolerance.

Research from all publishers

An all-natural plywood has been produced using self-adhesive bark veneers from rubber trees without added resins. Through delignification, epoxidation and densification, intrinsic biopolymers in the bark form “self-adhesive” networks, yielding plywood with high hardness, hydrophobicity and wear resistance. This approach eliminates synthetic binders, lowers thermal conductivity and offers large-scale, low-cost production of structurally robust panels. Complementary work has advanced light-activated polyacrylic acid (PAA) adhesives for bonding wood and bamboo substrates. A visible-light-catalysis platform affords mild curing, integrating hydrogen bonding, electrostatic interactions and mechanical interlocking to achieve bond strengths exceeding 20 MPa. The resulting bonds withstand extreme temperatures (−196 °C to 200 °C), long-term storage and solvents, and permit closed-loop recyclability via water-mediated dissociation.

Wood Fibre Processing publication trend

The graph below shows the total number of articles in wood fibre processing across all publications each year (not limited to Nature Index journals).

Technical terms

Delignification: Chemical removal or modification of lignin to expose and individualise cellulose fibres during pulping or densification.

Crosslinking: Formation of covalent bonds between polymer chains (e.g., lignin–phenolic, protein–catechol) that reinforces adhesive networks.

Densification: Compression of porous wood or bamboo matrices, optionally after chemical treatment, to raise density, strength and stiffness.

Thermomechanical pulping (TMP): Mechanical refining of wood chips at elevated temperatures to liberate fibres while retaining lignin.

Non-isocyanate polyurethane (NIPU): A polyurethane analogue synthesised without toxic isocyanates by reacting cyclic carbonates or other precursors with polyamines.

Waterborne adhesive: A bonding formulation in which the active polymer (e.g., lignin suspension) is dispersed or dissolved in water for environmentally friendly application.

References

1. Light‐Driven PAA Adhesive: A Green Bonding Platform Integrating High‐Performance, Environmental Resilience, and Closed‐Loop Recyclability. Advanced Science (2025).
2. A self‐adhesive bark veneer for all‐natural plywood. EcoMat (2023).
3. Bonding wood with uncondensed lignins as adhesives. Nature (2023).
4. Robust flexural performance and fracture behavior of TiO2 decorated densified bamboo as sustainable structural materials. Nature Communications (2023).