Phenolated lignin nanoparticle-reinforced regenerated cellulose films via ZnCl2/AlCl3 hydrate dissolution for food packaging

Petroleum-based plastic packaging stays in the environment longer and raises safety concerns, prompting the development of sustainable bio‑based alternatives. Herein, high‑performance regenerated cellulose (RC) films reinforced with phenolated lignin nanoparticles (P‑LNPs) were developed by dissolving softwood pulp in an ZnCl 2 /AlCl 3 inorganic molten salt hydrate system and regenerating it in water. Phenolation increased lignin’s phenolic–OH content, and nanolization allowed for uniform nanoparticle dispersion and strong interfacial interactions within the cellulose matrix. At 3 wt% P‑LNPs (RCPL‑3), the composite film showed a balanced profile: tensile strength of 89.14 MPa; elongation at break of 9.47%; water vapor permeability of 0.91 × 10⁻¹ ² g·cm/(cm²·s·Pa); visible‑light transmittance of 83.78%; UV blocking over 90%; and a water contact angle of 103.2°. The films possess antioxidant activity and inhibit the growth of Escherichia coli and Staphylococcus aureus . In a model application, RCPL-3 effectively slowed banana peel browning and reduced 7-day weight loss to 18%. Soil burial tests confirmed biodegradability with 71% mass loss after 60 days. These findings show that P-LNPs work together with regenerated cellulose to produce transparent, barrier-improved, antioxidant, and antibacterial films suitable for active, biodegradable food packaging.