Interphase Engineering of Epoxy/Wool Biocomposites via Lignin Coating: Effects on Mechanical and Hygrothermal Performance
5 affiliations
- 1Department of Chemical Engineering Materials Environment, Sapienza University of Rome, 00184 Rome, Italy
- 2Institute for Materials Research and Innovation, University of Greater Manchester, Bolton BL3 5AB, UK
- 3Luxembourg Institute of Science and Technology (LIST), L-4362 Esch-sur-Alzette, Luxembourg
- 4Department of Materials Engineering, University of Leuven (KUL), 3001 Leuven, Belgium
- 5Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123 Perugia, Italy
Abstract
This work has investigated epoxy composites reinforced with wool fabrics modified by an organosolv lignin coating deposited via a sustainable protocol. The lignin layer was introduced to tailor the fiber/matrix interphase, aiming to improve adhesion and reduce water-related degradation associated with the intrinsic hygroscopicity of wool. Laminates were manufactured by vacuum-assisted resin transfer molding (VARTM) and systematically characterized. Thermogravimetric analysis demonstrated improved thermal stability and higher char yield in lignin-coated composites. Mechanical tests revealed enhanced flexural strength (+21%) and modulus (+31%), together with a modest increase in interlaminar shear strength. SEM analysis of the fracture surfaces provided additional evidence of changes in fiber–matrix interfacial interactions. Low-velocity impact and DMA results further supported the role of the coating in improving load transfer and viscoelastic response. Water absorption tests indicated reduced equilibrium uptake and slower diffusion kinetics, highlighting the hydrophobic barrier function of the lignin layer. Collectively, these results show that the lignin coating acts primarily as an interphase modifier and water-barrier layer, enabling low-value wool fabrics to be upgraded into functional reinforcements for more durable epoxy biocomposites.
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BibTeX
@article{pantaleoni2026interphase,
title = {{Interphase Engineering of Epoxy/Wool Biocomposites via Lignin Coating: Effects on Mechanical and Hygrothermal Performance}},
author = {Alessia Pantaleoni and Baljinder K. Kandola and A. Richard Horrocks and Irene Bavasso and Maria Paola Bracciale and Erika Palazzi and Carlos A. Fuentes and Khouloud Tilouche-Guerdelli and Jacopo Tirillò and Assunta Marrocchi and Fabrizio Sarasini},
journal = {Polymers},
year = {2026},
month = nov,
doi = {10.3390/polym18212756},
url = {https://www.mdpi.com/2073-4360/18/21/2756},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Interphase Engineering of Epoxy/Wool Biocomposites via Lignin Coating: Effects on Mechanical and Hygrothermal Performance
AU - Alessia Pantaleoni
AU - Baljinder K. Kandola
AU - A. Richard Horrocks
AU - Irene Bavasso
AU - Maria Paola Bracciale
AU - Erika Palazzi
AU - Carlos A. Fuentes
AU - Khouloud Tilouche-Guerdelli
AU - Jacopo Tirillò
AU - Assunta Marrocchi
AU - Fabrizio Sarasini
PY - 2026
DA - 2026/11/05
JO - Polymers
DO - 10.3390/polym18212756
UR - https://www.mdpi.com/2073-4360/18/21/2756
AB - This work has investigated epoxy composites reinforced with wool fabrics modified by an organosolv lignin coating deposited via a sustainable protocol. The lignin layer was introduced to tailor the fiber/matrix interphase, aiming to improve adhesion and reduce water-related degradation associated with the intrinsic hygroscopicity of wool. Laminates were manufactured by vacuum-assisted resin transfer molding (VARTM) and systematically characterized. Thermogravimetric analysis demonstrated improved thermal stability and higher char yield in lignin-coated composites. Mechanical tests revealed enhanced flexural strength (+21%) and modulus (+31%), together with a modest increase in interlaminar shear strength. SEM analysis of the fracture surfaces provided additional evidence of changes in fiber–matrix interfacial interactions. Low-velocity impact and DMA results further supported the role of the coating in improving load transfer and viscoelastic response. Water absorption tests indicated reduced equilibrium uptake and slower diffusion kinetics, highlighting the hydrophobic barrier function of the lignin layer. Collectively, these results show that the lignin coating acts primarily as an interphase modifier and water-barrier layer, enabling low-value wool fabrics to be upgraded into functional reinforcements for more durable epoxy biocomposites.
SN - 2073-4360
ER -