Effects of Ozone Exposure on the Structural, Mechanical and Barrier Properties of Select Plastic Packaging Films By Banu F. Ozen, 1 Lisa J. Mauer 1 * and John D. Floros 2 1 Food Science Department, Purdue University, 745 Agriculture Mall Drive, West Lafayette, IN 47907, USA 2 Food Science Department, Pennsylvania State University, 111 Borland Laboratory, University Park, PA 16802, USA The effects of ozone (O 3 ) gas exposure at various concentrations and treatment times on structural, mechanical and barrier properties of polyethylene and polyamide ®lms were investigated. Changes in the structure of the ®lms were monitored using an FT-IR spectrometer. The results showed that O 3 treatment affectedpolyethyleneandpolyamide®lmsdifferently.WhileO 3 treatmentcaused formation of oxygen-containing functional groups and degradation of polymeric chains in polyethylene ®lms, O 3 treatment of polyamide ®lms signi®cantly increased the ±C±N± stretch observed at 1125 cm À1 in the FT-IR spectra. The changes in the mechanical properties of polyethylene ®lms depended on the O 3 treatment conditions (temperature and O 3 concentration were the most signi®cant), but an increase in tensile strength of polyamide ®lms was observed regardless of the treatment conditions. Permeability to O 2 forbothtypesof®lms decreased with increasing O 3 treatment time. Copyright O 2003 John Wiley & Sons, Ltd. Received 15 July 2002; Accepted 15 January 2003 KEY WORDS: ozone; FT-IR; polyethylene; polyamide INTRODUCTION Ozone (O 3 ) gas has increasingly been used to treat or sterilize foods, potable water, food processing equipment and packaging materials due to its oxidizing and disinfectant properties. Several characteristics of O 3 gas, including its wide range of antimicrobial activity and easy degradation without toxic by-products, make it particularly attractive for treatment of food and food-contact surfaces. Treatment of a food product with O 3 gas could be performed in several ways: (a) treat the food product with O 3 gas and then package it; 1 (b) store the packaged product in a O 3 gas-controlled environment to allow the O 3 to diffuse into the package; 2,3 or (c) ¯ush the packaged food with the desired O 3 gas mixture. To achieve the desired sterility of the food product, O 3 treatment times and concentrations are often higher than those used for package sterilization alone, and it is important to understand how these treatment conditions could affect packaging materials. O 3 treatment has been shown to modify polymer surfaces to control the surface adhesion of bacterial cells. 4±6 Since O 3 is a very strong oxidizing agent, exposure to O 3 results in changes in the properties of polymeric materials. Recent research related to O 3 and packaging has focused PACKAGING TECHNOLOGY AND SCIENCE Packag. Technol. Sci. 2002; 15: 301±311 DOI:10.1002/pts.602 Copyright  2003 John Wiley & Sons, Ltd. * Correspondence to: L. J. Mauer, Food Science Department, Purdue University, 745 Agriculture Mall Drive, West Lafayette, IN 47907, USA. Email: mauer@foodsci.purdue.edu.