Preparation of low‐density polyethylene‐ and poly (lactide)/poly (butylene adipate‐co‐terephthalate)‐based antibacterial films integrated with elemental sulfur and sulfur nanoparticles

Abstract

Antibacterial low‐density polyethylene (LDPE)‐ and poly (lactide)/poly (butylene adipate‐co‐terephthalate) (PLA/PBAT)‐based films incorporated with elemental sulfur (ES) and sulfur nanoparticles (SNPs) were prepared using a blow extrusion method for food packaging applications. Flexible and free‐standing films were manufactured using an industrial processing method without any modification. The films were characterized using ultraviolet (UV)–visible spectroscopy, field emission scanning electron microscope (FESEM), X‐ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). Also, film properties include optical, mechanical, surface hydrophobicity, thermal stability and antibacterial activity. The addition of ES and SNP significantly reduced the light transmittance (both UV and visible light) of LDPE‐ and PLA/PBAT‐based films and slightly reduced mechanical properties but did not affect thermal stability. The ES‐ and SNP‐added films showed apparent antibacterial activity against the Gram‐positive foodborne pathogenic bacteria (Listeria monocytogenes). In general, SNP showed superior film properties and antibacterial properties compared to ES, but ES also showed comparable properties as SNP. Antibacterial LDPE‐ and PLA/PBAT‐based films can be produced on an industrial scale and used in the packaging of refrigerated foods susceptible to L. monocytogenes contamination.