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Lignin-based composite coatings enhance UV protection and barrier performance of paper packaging
A new study demonstrates how lignin-based composite coatings significantly improve the strength, barrier properties and UV shielding of cellulosic paper – offering a sustainable pathway for advanced food packaging.
The demand for sustainable food packaging with reliable UV protection is rising, as light exposure can cause off-flavours, discolouration and nutrient loss. Researchers have now developed a novel multifunctional composite coating combining cellulose nanocrystals (CNCs) and sodium lignosulfonate (SL), cross-linked with polyvinyl alcohol (PVA).
This coating forms a hydrogen-bonded network, enhancing mechanical integrity and barrier performance. In particular, the SL-4/C/P formulation with an SL/CNC mass ratio of four to one achieved 98 % UV shielding in the UVA region and almost complete UVB blocking.
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Improved strength and reduced permeability
Beyond UV protection, the coating increased the paper’s tensile index by 126 % and folding endurance by 308 %. The Cobb30 value dropped from 66 g/m² to 56 g/m², indicating better water resistance, while air permeability was reduced from 124 mm/s to 52 mm/s.
These findings present a sustainable strategy for upgrading food packaging paper, while promoting the high-value use of lignin and cellulose nanocrystals in the paper industry.
Source: Xie, K., Luo, T., Wang, L., Wang, J., Liu, W. & Tang, Y., Fabrication of multifunctional lignin-based composite coatings for enhanced strength, barrier properties and UV protection of cellulosic paper. Progress in Organic Coatings, 207, 109429 (2025).
