Preparation of poly(lactide)/lignin/silver nanoparticles composite films with UV light barrier and antibacterial properties

Organosolv lignin was used as a reducing agent for the preparation of silver nanoparticles (AgNPs) and their incorporation into poly(lactide) (PLA) polymer to prepare composite films. The composite films were characterized using UV-vis spectroscopy, FE-SEM, FTIR, XRD, and TGA. The optical, mechanical, water vapor barrier, and antibacterial properties of the composite films were evaluated. The UV-vis spectra of films exhibited two characteristics peaks around 300 and 450 nm attributed to lignin and AgNPs, respectively. XRD results indicated that the crystalline AgNPs had been formed. The transmission of light at 280 nm decreased significantly after incorporation of lignin and AgNPs. FTIR results showed that there was no change in the chemical structure of PLA after incorporation of lignin and AgNPs. The mechanical and water vapor barrier properties of the composite films increased after lignin and AgNPs incorporation, The films containing AgNPs exhibited potent antibacterial activity against Escherichia coli and Listeria monocytogenes.