Selective Ethylene-Permeable Zeolite Composite Double-Layered Film for Novel Modified Atmosphere Packaging

The composite double-layered films, for the packaging application of postharvest fruits and vegetables, were prepared by laminating low-density polyethylene (LDPE) and poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) modified with zeolite ZSM-5. The film was characterized by scanning electron microscope and differential scanning calorimeter and tested for permeation of ethylene (C2H4), oxygen (O-2), carbon dioxide (CO2), and water vapor. It was found that the C2H4 permeability of the films was improved because of an enhanced adsorption of C2H4 by the incorporated zeolite (0-10 wt%). The preconcentrated layer (zeolite/SEBS) leads to a higher C2H4 concentration gradient across the film. Moreover, the high dispersion of zeolite increased the C2H4 permeation. When compared with O-2 and CO2, the composite films were more selective to C2H4. However, the C2H4 permeation decreased in the presence of O-2 because of a competitive adsorption. In addition, the films possessed appreciate tensile properties for packaging application. POLYM. ENG. SCI., 51:1264-1272, 2011. (C) 2011 Society of Plastics Engineers