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Fully bio-based coating protects Lyocell from fire and bacteria
Researchers have developed a fully bio-based phosphorus-nitrogen synergistic coating for Lyocell fabrics using phytic acid and gelatin. The coating delivers strong flame retardancy and antibacterial activity while preserving the wearability of the treated textile.
Cellulosic textiles such as Lyocell are valued for their sustainability and comfort, but their high flammability and susceptibility to microbial growth limit their use in protective applications. A new study presents a fully bio-based coating system that addresses both challenges without compromising fabric properties. The coating, designated PAGe, combines phytic acid (PA) and gelatin (Ge) to form a phosphorus-nitrogen synergistic network on the fibre surface.
With a loading of only 3.2 wt% PAGe, the treated Lyocell fabrics reached a limiting oxygen index (LOI) of 28.9 % and successfully passed the vertical burning test (VBT). Compared with untreated Lyocell, the peak heat release rate (pHRR) was reduced by 50.5 %, indicating a marked improvement in fire safety.
Synergistic charring mechanism and antibacterial activity
Mechanistic analyses showed that PAGe catalyses the early dehydration of both itself and the underlying Lyocell fibres, promoting the formation of an intumescent, dense and continuous protective char layer. This layer effectively insulates the substrate from heat and restricts mass transfer during combustion. In parallel, the presence of phytic acid salts and protonated amine groups (-NH3+) in the coating delivered antibacterial inhibition rates exceeding 99.99 % against both Staphylococcus aureus and Escherichia coli.
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Preserved wearability and sustainable potential
Beyond flame retardancy and hygiene performance, the coating enhanced the tensile strength of the fabrics while maintaining air permeability and hand value, all of which are critical for textile applications. The authors highlight that the fully bio-based formulation, combined with its multifunctional performance, offers a sustainable strategy for the development of protective Lyocell textiles. The approach may also serve as a blueprint for eco-friendly multifunctional coatings on other cellulosic substrates.
Source: Hu, L. et al., Construction of fully biomass coating on Lyocell fabrics by gelatin containing phosphorus for superior fire safety, antibacterial performance and wearability. Progress in Organic Coatings, 110117 (2026).
