Submitted to: Journal of Applied Polymer Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/2/2009
Publication Date: 2/5/2010
Citation: Netramai, S., Rubino, M., Aurus, R., Annous, B.A. 2010. Effect of chlorine dioxide gas on physical, thermal, mechanical, and barrier properties of polymeric packaging materials. Journal of Applied Polymer Science. 115:1742-1750. Interpretive Summary: In 2001, the FDA approved the incorporation of chlorine dioxide gas (ClO2), a strong oxidizing agent, within food packaging materials to be used for uncooked meats, such as poultry and seafood. If the package is going to be considered as a strategy for the release and application of ClO2 gas, the mass transfer properties of ClO2 need to be determined since it will impact the selection of material with appropriate barrier to such gas. In the first part of our study, permeability, diffusion, and solubility coefficients of ClO2 were determined for 10 types of polymeric packaging materials. However, the exposure of polymeric material to oxidizing agents under different applied conditions could lead to changes in the overall performance of the polymeric materials. Thus, the specific objectives of this work were to determine and evaluate the effects of exposure of gaseous ClO2 on a) chemical, b) physical, c) mechanical, and d) barrier properties of the 10 types of polymeric packaging materials. Changes in characteristics of these packaging materials following exposure to ClO2 varied. Currently, we are evaluating the incorporation of different polymeric material for the development of a film with optimal performance in the presence of ClO2.
Technical Abstract: In the first part of our study we determined permeability, diffusion, and solubility coefficients of gaseous chlorine dioxide (ClO2) through the following packaging material: biaxial-oriented polypropylene (BOPP); polyethylene terephthalate (PET); poly lactic acid (PLA); multilayer structure of ethylene vinyl acetate (EVA) and ethylene vinyl alcohol (EVOH) [EVA/EVOH/EVA]; polyethylene (PE); polyvinyl chloride (PVC); polystyrene (PS); nylon. However, strong oxidizing agents such as ClO2 can cause oxidative degradation of these packing materials. The effects of ClO2 on properties, and performance of selected polymeric packaging materials were assessed by their IR spectrum, physical, mechanical, barrier, and color properties. The samples were exposed to 3,600 ppm ClO2 at 23 C for up to 14 days. The IR spectra of the exposed samples indicated many changes in their chemical characteristics, such as the formation of polar groups in polyolefins, the changes in functional groups, the main chain scission degradation, as well as, the possible chlorination in several sample types. The exposed PEs samples showed a decrease in tensile properties. Decreases in barrier to moisture, oxygen and/or carbon dioxide were observed in PVC, PET and multilayer EVA/EVOH/EVA. On the other hand, significant increase in barrier to O2 was observed in the exposed nylon, which could be the result of the molecular reordering in the exposed sample, as implied through the increase in the crystallinity of the material.