Properties of poly (vinyl alcohol) films with embedded zeolitic imidazolate framework (ZIF‐8) nanoparticles for food packaging applications

Abstract

AbstractThis study evaluated the physical, mechanical, barrier properties, and transition temperatures of poly (vinyl alcohol) (PVA) films with embedded zeolitic imidazolate framework‐8 (ZIF‐8) nanoparticles carrying a natural antimicrobial, trans‐cinnamaldehyde (TC). The ZIF‐8 nanoparticles were synthesized using a sonochemical method and incorporated into polymeric matrices at mass ratio concentrations of 0% (control film) to 5% weight of ZIF‐8@TC to PVA. Solutions were mixed, cast onto Petri dishes and dried for 12 h at 37°C in a ventilated oven. The film samples were stored in airtight containers at room temperature and used within 1 week. The engineering properties of the PVA/ZIF‐8@TC films were compared with those of low‐density polyethylene (LDPE) film commonly used for packaging of spinach leaves. The glass transition, melting, and crystallization temperatures of PVA compositive films all increased (p < 0.05) with ZIF‐8@TC concentration. When exposed to high relative humidity environments, the PVA/ZIF‐8@TC films had lower equilibrium moisture content (p < 0.05) than the LDPE film. Although the composite films have different tensile properties from the LDPE film, embedding ZIF‐8@TC into PVA films improved the tensile strength by 17%, making the PVA/ZIF‐8@TC films suitable for low load‐bearing applications such as food packaging. The gas barrier properties of PVA‐based films differed only slightly with added ZIF‐8@TC (p < 0.05).Practical ApplicationPVA/ZIF‐8@TC films are appropriate environment‐friendly alternatives to polymeric food packaging in terms of their functional properties.