Effects of Ag ion substitution in zeolite and use of citric acid on the efficacy of antimicrobial properties of EVA‐PE composite films

Abstract

Porous zeolites substituted with Ag ions (Ag[zeolite]) or citric acid‐dealuminated Ag[zeolite] (CA‐Ag[zeolite]) were incorporated into an ethylene–vinyl acetate (EVA) and polyethylene (PE) copolymer using an extrusion process. The antimicrobial effects of the resulting films were evaluated against Escherichia coli, Staphylococcus aureus, and Human coronavirus 229E, and their physical and tensile properties were examined. CA‐Ag[zeolite] exhibited superior antibacterial results compared to Ag[zeolite] for both bacteria, and the CA‐Ag[zeolite]‐EVA‐PE film demonstrated higher antimicrobial effects against the tested microorganisms than the Ag[zeolite]‐EVA‐PE film. Surface elemental analysis, determination of the specific surface areas, and pore size investigations demonstrated that CA‐Ag[zeolite] possessed higher hydrothermal stability than the zeolite or Ag[zeolite] alone. Furthermore, the CA‐Ag[zeolite]‐EVA‐PE film exhibited a higher L* value and lower a* and b* values than the Ag[zeolite]‐EVA‐PE film along with lower absorbance. The former also demonstrated higher tensile strength and moisture permeability, in addition to lower roughness values on both its cross‐section and surface. Moreover, the Ag[zeolite]‐EVA‐PE and CA‐Ag[zeolite]‐EVA‐PE films exhibited higher thermal decomposition temperatures than the EVA‐PE composite. Overall, the CA‐Ag[zeolite]‐EVA‐PE film showed potential for use as a novel antimicrobial film for application in food packaging and kitchen utensil coating materials.Highlights Antimicrobials were prepared with EVA/PE, Ag[zeolite], and citric acid (CA) EVA/PE films containing Ag[zeolite] and CA showed strong antimicrobial effects CA addition improved Ag[zeolite] distribution in the film and the film color CA addition enhanced the tensile, moisture barrier, and thermal properties Potential applications include antimicrobial packaging and utensil coatings