Rapid and efficient preparation of cationized lignin for downstream high value-added utilization of biodegradable antimicrobial nanofibrous membranes

Industrial lignin is underutilized as an abundant natural aromatic resource, resulting in a serious waste of biomass resources. In this study, a strategy was developed to efficiently achieve cationization of industrial lignin, which not only could increase the water solubility of the industrial lignin for good compatibility with polyvinyl alcohol (PVA), but also incorporated quaternary ammonium groups to improve the antimicrobial performance. The results showed that the cationized lignin products could be obtained by reacting at 75 °C for only 20 min and had good compatibility with PVA in aqueous systems, which not only shortened the lignin cationization time, but also reduced the amount of cationization reagent. By integrating the electrospinning technique, the nanofiber membranes with excellent antimicrobial performance can be produced for the field of medical dressing. With the addition of 7 wt% of the cationized lignin, the novel developed antimicrobial nano-medical dressing exhibited excellent breathability (61.08 mm/s), anti-UV properties, and compatibility with portable spinning technique. In addition, the cationized lignin-based nanofiber membranes had excellent antimicrobial performance, with an antimicrobial ratio of 100 % (Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli), as well as being biodegradable. In conclusion, this strategy could realize the cationization modification of industrial lignin while expanding the application in medical dressings and improving the economic sustainability of biorefinery strategies.