A High Barrier and Sustained Release Oxygen-Absorbing Ionic Polymer for Food Packaging Applications

Development and utilization of oxygen absorbing materials for food and beverage packaging are important to protect the oxygen-sensitive foods. In this study, we developed a kind of ionic polymer with excellent oxygen absorbing ability based on reacting ethylene-acrylic acid copolymer (EAA) and sodium sulfite (Na₂ SO₃ ). By virtue of the hydrophilicity of the ionic polymer, the sulfite in Na₂ SO₃ is easily hydrolyzed and ionized. The oxygen inhalation reaction was gradually initiated and started, whereas achieved a slow and controllable oxygen absorption process. The oxygen absorbing agent can be directly added in the form of an auxiliary agent, which greatly simplifies the preparation process of the oxygen absorbing material. Furthermore, the ionic structure of the EAA/Na₂ SO₃ composites were destroyed and mechanical properties of the material did not decrease after oxygen absorption. More importantly, it can effectively prevent the entry of external oxygen because the ionic polymer itself has better barrier properties. PRACTICAL APPLICATION: Typical oxygen-sensitive objects include: beer, coffee, canned food, meat products, dairy products, and so on. The presence of oxygen in the package can cause microbial growth, odor generation, color change and nutrient loss, resulting in a significant reduction in food shelf life. Therefore, controlling the oxygen content of the food package is important to limit the rate of these spoilage and spoilage reactions in the food. Materials with active oxygen scavenging and good barrier properties and packaging performance are highly economically viable in terms of improving product quality and reducing packaging costs.