One Step to Simultaneously Improve the Antibacterial Activity and Compatibility with PBAT of Nanolignin via Surface Modification

Lignin is a natural and nontoxic biomass material. It not only has antibacterial activity but also exhibits antioxidation and UV shielding properties, which has great potential application in food packaging, and the medical fields. However, with the complex structure, the antibacterial efficiency of lignin is quite low. It is therefore necessary to improve the antibacterial performance of lignin to broaden its applications. In this study, LZM hybrid nanoparticles with ZnO, long-chain quaternary ammonium salt structures were prepared by simple self-assembly method. Antibacterial activity and compatibility with PBAT of nanolignin was achieved in one step via surface modification. The antibacterial rates against E. coli and S. aureus of LZM nanoparticles reached up to 100%. Subsequently, LZM hybrid nanoparticles were filled into PBAT by solvent casting to prepare PBAT/LZM composite films, which showed a good compatibility between LZM and PBAT. LZM hybrid nanoparticles exhibit reinforcing and toughening effects on the composites. Especially, the tensile strength of the PBAT-3%LZM composite film is increased from 33.2 to 37.6 MPa. Meanwhile, the bacterial adhesion concentration of PBAT-3%LZM composite to E. coli decreases from 14 × 105 CFU/mL to 6 × 104 CFU/mL, while PBAT-3%LZM no longer adheres to S. aureus. Furthermore, the UV shielding of PBAT-2%LZM at λ = 320 nm is more than 99.0%. These interesting results will support the composite films to be applied in food packaging and medical devices. Hence, LZM has simultaneously LNPs’ antibacterial activity and compatibility with PBAT.