Preparation and evaluation of oxygen scavenging nanocomposite films incorporating cellulose nanocrystals and Pd nanoparticles in poly(ethylene-co-vinyl alcohol)

There is current interest in active packaging, where the packaging material exhibits desirable functions in addition to containment of product. One of these functions is to reduce the oxygen content in the package in order to minimize product oxidation and spoilage, and prolong product shelf-life. In this work, we have developed novel nanocomposites, comprising cellulose nanocrystals and Pd nanoparticles embedded in an ethylene–vinyl alcohol copolymer (EVOH). The nanocellulose is a critical component in the nanocomposite because it acts not only as reducing agent for PdCl₂ but also as support for the dispersion of Pd nanoparticles on EVOH film and enhances the physical properties of the EVOH. Pd nanoparticles react with oxygen to serve as oxygen scavenger. The cellulose nanocrystals have also been optionally oxidized, and the increased presence of carboxyl groups favored a better distribution of the Pd nanoparticles, thereby enabling improved oxygen absorption. These features make the nanocomposites promising candidates as active packaging materials. Included in this work are the preparation and the characterization of these materials.