Changing paradigm of wood adhesives: sustainable resins based on high-consistency lignin dispersions
- Federica Maria Camilla Ferruti
- The pursuit of renewable resources for sustainable materials has drawn attention to lignin, a major component of wood and byproduct of pulp and paper industry. The present study exploits the polyfunctionality of lignin for the development of phenol- and formaldehyde- free adhesives suitable for wood substrates. An original procedure allowed obtaining high-consistency lignin waterborne nanoformulations which were then used as binders in bicomponent adhesives in mixture with appropriate hardeners. The selection of all materials and processes was inspired by principles of safety, energy efficiency, and sustainability, ensuring scalability to 5 kg and beyond. The resulting adhesives granted excellent mechanical strength and water resistance to plywood prototypes, outperforming the technological requirements outlined in the EN 314-2 standard for class 1 and class 2 adhesives. The adhesion performance of the developed formulations, along with their low carbon footprint associated to the high lignin content, make them promising and competitive alternatives to traditional fossil-based adhesives for indoor and outdoor wood furniture and constructions. This research is embedded in the TREECURE project, funded by the Knut och Alice Wallenbergs Stiftelse under the Wallenberg Launch Pad (WALP) Proof-of-Concept programme, promoting research initiatives making an impact in industry and society. The project aims at the development of wood adhesives for safe built environments, relying on technologies alternative to phenol-formaldehyde resins.