Cold plasma-enhanced polylactic acid/chitosan films incorporating zein nanoparticles: a promising strategy for developing food packaging materials
Mahdi Norozi, Seyed Hadi Peighambardoust, Sirous Khorram, Hamed Hamishehkar
Abstract
This study developed packaging films using polylactic acid (PLA) and chitosan incorporated with zein nanoparticles (Z-NPs) for active packaging applications. Dielectric barrier discharge (DBD) air plasma treatment was applied to improve adhesion between PLA and the nanocomposite film, resulting in a bilayer film. The plasma treatment reduced the water contact angle from 98.2° to 42.6° and increased surface roughness from 19.75 nm to 31.5 nm, as confirmed by atomic force microscopy. The optimally plasma-treated PLA showed an 80% increase in tensile strength, while the bilayer film exhibited improved water vapor permeability of 0.64 × 10 −7 g/m.h.Pa. The incorporation of 15% Z-NPs into the chitosan matrix enhanced the mechanical properties, with a 20 % increase in tensile strength and a 15 % decrease in water vapor permeability. The bilayer film demonstrated a 40 % increase in tensile strength and a 30 % decrease in water vapor permeability compared to the neat PLA film. Additionally, the bilayer film showed enhanced antibacterial activity against S. aureus , with a 6mm inhibition zone. The results demonstrate that the combination of plasma treatment and Z-NPs incorporation significantly enhances the properties of biodegradable packaging materials, offering a sustainable alternative for the food industry with improved mechanical and barrier properties.