A new lignin-based polyurethane film for wood : decay, artificial weathering, physical and morphological characterization

Tamantini, Swati (author), Bergamasco, Sara (author), Humar, Miha (author), Petrič, Marko (author), Romagnoli, Manuela (author)

Lignin-based polyurethanes represent a promising strategy for developing more sustainable wood coatings by partially replacing fossil-derived polyols with renewable aromatic biopolymers. In this study, a polyurethane formulated with organosolv lignin (LPU) was synthesized and applied on two non-durable European wood species, Fagus sylvatica L. and Picea abies L., and compared with a commercial fossil-based polyurethane (CPU). Coated samples were evaluated for color stability, gloss evolution, wettability, adhesion, impact and scratch resistance, and biological durability. Accelerated ageing was performed under xenon-light irradiation, while decay resistance was assessed against Gloeophyllum trabeum and Trametes versicolor. Additional tests examined susceptibility to blue-stain fungi and surface morphology via SEM. LPU produced a matte film with intrinsically darker coloration but excellent chromatic stability and minimal gloss variation during ageing. Its initial hydrophobicity was higher on beech and comparable to CPU on spruce. Although CPU exhibited superior adhesion and slightly better mechanical resistance, LPU provided enhanced protection against blue-stain fungi—particularly on spruce—and a more uniform response to decay fungi across wood species. Overall, despite its darker appearance, the lignin-based formulation offered functional protection comparable to the commercial coating, confirming its potential as a viable bio-based alternative for above-ground wood applications.

• Language: English
• Keywords: wood durability, wood decay, beech, spruce, coating, blue stain, Gloephyllum trabeum, Trametes versicolor, contact angle, adhesion
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Publication date: 01.12.2025
• Year: 2025
• Number of pages: 20 str.
• Numbering: Vol. 30, issue 24, [article no.] 4793
• PID: 20.500.12556/RUL-177134
• UDC: 630*84
• ISSN on article: 1420-3049
• DOI: 10.3390/molecules30244793
• COBISS.SI-ID: 261712899
• Publication date in RUL: 16.12.2025

Record is a part of a journal

• Title: Molecules
• Shortened title: Molecules
• Publisher: MDPI
• ISSN: 1420-3049
• COBISS.SI-ID: 18462981

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: naravna odpornost lesa, razkroj lesa, bukev, smreka, premaz, glive modrivke, navadna tramovka, pisana ploskocevka, kontaktni kot, adhezija

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P4-0015
• Name: Les in lignocelulozni kompoziti

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: 0481-09
• Name: IC za pripravo, staranje in terensko testiranje lesa ter lignoceluloznih materialov
• Acronym: OC LES PST