Lignin nanoparticles modified with tall oil fatty acid for cellulose functionalization

In this study, tall oil fatty acid ester of softwood kraft lignin (TOFA-L) was used to prepare TOFA lignin nanoparticles (TLNP) in water. The average diameters for two prepared TLNPs in 0.1 mg/ml concentration were 140 nm and 160 nm. TLNPs were attached covalently onto modified and unmodified cellulose fibres to form an antimicrobial composite material. The modified cellulose fibres contained reactive allylic double bonds with a degree of substitution of 0.05. The antimicrobial properties of both TLNPs and TLNP coated fibres (TLNP-C) were studied against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa using silver nanospheres (average size 10 nm) and Lignoboost lignin particles with 300 and 400 nm sizes as references. Antimicrobial activity of the samples was stronger against Gram-positive S. aureus cells than against Gram-negative target microbes E. coli and P. aeruginosa.