Lignin Nanoparticles for Enhancing Physicochemical and Antimicrobial Properties of Polybutylene Succinate/Thymol Composite Film for Active Packaging

Abstract

The natural abundance polymer stability biodegradability and natural antimicrobial properties of lignin open a wide range of potential applications aiming for sustainability. In this work the effects of 1% (w/w) softwood kraft lignin nanoparticles (SLNPs) on the physicochemical properties of polybutylene succinate (PBS) composite films were investigated. Incorporation of SLNPs into neat PBS enhanced Td from 354.1 ?C to 364.7 ?C determined through TGA whereas Tg increased from ?39.1 ?C to ?35.7 ?C while no significant change was observed in Tm and crystallinity analyzed through DSC. The tensile strength of neat PBS increased to 35.6 MPa when SLNPs were added to it. Oxygen and water vapor permeabilities of PBS with SLNPs decreased equating to enhanced barrier properties. The good interactions among SLNPs thymol and PBS matrix and the high homogeneity of the resultant PBS composite films were determined through FTIR and FE-SEM analyses. This work revealed that among the PBS composite films tested PBS + 1% SLNPs + 10% thymol showed the strongest microbial growth inhibition against Colletotrichum gloeosporioides and Lasiodiplodia theobromae both in vitro through a diffusion method assay and in actual testing on active packaging of mango fruit (cultivar 揘am Dok Mai Si Thong�). SLNPs could be an attractive replacement for synthetic substances for enhancing polymer properties without compromising the biodegradability of the resultant material and for providing antimicrobial functions for active packaging applications. ? 2023 by the authors.