Bio-Based Adhesives in Wood Composites

Wood composites rely traditionally on synthetic resins such as urea–formaldehyde and phenol–formaldehyde to achieve high bonding strength and durability. Growing environmental and health concerns have driven research towards adhesives derived entirely or predominantly from renewable biomass. Key feedstocks include lignin, tannin, plant proteins and polysaccharides, which offer functional groups capable of forming robust interfacial bonds with wood fibres. Advances in extraction and chemical modification have enabled direct application of uncondensed lignin suspensions, biomimetic co-crosslinking with catechol moieties and light-activated polymerisation of aqueous systems. These innovations promise lower emissions of volatile organic compounds, reduced reliance on fossil resources and enhanced recyclability. Applications span structural plywood and particleboard to high-performance joinery, supporting a circular-economy model in the timber sector and responding to stringent indoor-air quality regulations.

Research from Nature Portfolio

Recent studies have demonstrated a simple route to isolate uncondensed lignin directly from lignocellulosic biomass and apply it as a waterborne adhesive for wood veneers. Plywood panels bonded with such lignin suspensions exhibit comparable mechanical performance across a range of pressing temperatures and enhanced environmental credentials compared with formaldehyde-based resins. Mechanistic investigations reveal that water plasticises the lignin, enabling vessel filling and in situ crosslinking with cell-wall phenolics to yield strong interfacial adhesion. Foundational work on soybean-meal adhesives enhanced by natural catechol-inspired crosslinkers has further shown that polyphenol–protein networks can achieve wet bonding strengths that meet interior plywood standards, highlighting the potential of biomimetic chemistry to replace synthetic binders in humid conditions.

Bio-Based Adhesives in Wood Composites publication trend

The graph below shows the total number of articles in bio-based adhesives in wood composites across all publications each year (not limited to Nature Index journals).

Technical terms

Lignin: An abundant aromatic biopolymer in plant cell walls used to confer phenolic functionality in wood adhesives.

Crosslinking: Chemical bonding between polymer chains that enhances adhesive cohesion and mechanical stability.

Catechol moiety: A di-hydroxybenzene unit that mimics mussel adhesion chemistry to improve wet bond strength.

Polyacrylic acid (PAA): A water-soluble polymer platform capable of multiple non-covalent interactions and photocatalytic curing.

Non-isocyanate polyurethane (NIPU): A polyurethane analogue formed without toxic isocyanates, using cyclic carbonates or amines to react with polyols.

References

1. Bonding wood with uncondensed lignins as adhesives. Nature (2023).
2. Light‐Driven PAA Adhesive: A Green Bonding Platform Integrating High‐Performance, Environmental Resilience, and Closed‐Loop Recyclability. Advanced Science (2025).
3. A self‐adhesive bark veneer for all‐natural plywood. EcoMat (2023).
4. The synergy between natural polyphenol-inspired catechol moieties and plant protein-derived bio-adhesive enhances the wet bonding strength. Scientific Reports (2017).
5. Recent Developments in Lignin- and Tannin-Based Non-Isocyanate Polyurethane Resins for Wood Adhesives—A Review. Applied Sciences (2021).