Vigilancia Tecnológica

Particle dispersion assessment of the EVOH composite films with NC, MCC, SiO2 and CNC, and subsequent production of multilayer films, with an EVOH inner layer (or EVOH with NC or MCC incorporation) and LDPE in the outer layers, to analyze optical and barrier properties, to examine the feasibility for use in flexible packaging.AbstractTo preserve food from moisture and oxygen, polymers, such as ethylene vinyl alcohol (EVOH) are used in multilayer structures to provide oxygen barrier, while low?density polyethylene (LDPE) is used for a water vapor barrier. While this material combination is functionally ideal, it may not comply with the new packaging recycling guidelines. Some European markets have implemented rules that limit the weight percentage of EVOH in LDPE films. One way to increase recyclability is by reducing the amount of EVOH in the film structure while maintaining the packaging's oxygen barrier properties. To achieve this, it is necessary to improve the barrier properties of EVOH. With this objective in mind, this study evaluated the incorporation of nanoclays (NC), cellulose microcrystals (MCC), silicon dioxide nanoparticles (SiO2), and cellulose nanocrystals (CNC) into an EVOH matrix. The results indicate that NC and MCC facilitate a stable blown film extrusion process and have a better dispersion in the EVOH matrix. Based on this finding, three?layer films (with an ABA configuration) consisting of LDPE (A) and EVOH (7??m layer) with 0.5 or 1?wt.% MCC or NC (B) were produced to protect the EVOH from moisture and enable blown film processing. The oxygen transmission rate (OTR) values were lowest for 0.5?wt.% NC and 1?wt.% MCC incorporation. Although the films with micro and nanoparticles had increased haze, this did not affect the visibility of the packaged food.