Zeolite Additives for Flexible Packaging Polymers: Current Status Review and Future Perspectives

Zeolites are interesting inorganic additives that could be employed for plastic packaging applications. Polyethylene (PE) and polypropylene (PP) are intensively used for packaging as they provide great performance at low cost, even though they have poor environmental sustainability and may be more valorized. Biodegradable polymers may therefore represent a more eco-friendly alternative, but still, they have limited applications due to their generally inferior properties. Therefore, this review focuses on the use of zeolites as additives for flexible packaging applications to mainly improve the mechanical and barrier properties of PE, PP, and some biodegradable polymers, possibly with antimicrobial and scavenging activities, by exploiting zeolites' cation exchange ability and adsorption properties. Film preparation and characterization have been investigated. The obtained enhancements regard generally higher gas barriers, elastic moduli, and strengths, along with thermal stability. Elongation at break decreased for all PE composites and tended to increase for other matrices. The use of zeolites as additives for polymer films is promising (mainly for biodegradable polymers); still, it requires overcoming some limiting drawbacks associated with the additive concentration and dispersion mainly due to matrix-additive incompatibility.