A Gallic Acid–Acrylic Acid Graft Copolymer With High Oxygen Absorption Properties

Abstract

Gallic acid (GA), a potential deoxidizer utilized in food packaging, exhibits a robust oxygen-absorbing effect, yet suffers from poor stability. When integrated into polymers, its oxygen-absorbing properties undergo a significant decline. This research is focused on graft copolymerizing GA with acrylic acid (AA) to create a water-absorbing resin (GA-PAA) that boasts high-oxygen-absorbing capabilities. This minimizes GA loss during production and eliminates the need for an alkaline environment for oxygen absorption. The single-variable method is being employed to investigate the impact of synthesis conditions on GA-PAA's performance. Initial findings indicate optimal performance with synthesis mass ratios of 7% GA, 0.6% initiator, and 0.2% cross-linking agent, along with an 80% degree of neutralization and a reaction temperature of 80°C. The GA-PAA is characterized as highly absorbent for both oxygen and water, confirming the successful grafting of GA. Well-synthesized resins exhibit a water absorption capacity of 452.2 g/g and an oxygen scavenging of 105.3 mL/g before hydration. Posthydration, oxygen scavenging displays a pattern of an initial sudden decrease, followed by a gradual increase, dependent on the amount of water added. These findings suggest that grafting AA with GA enhances GA's stability during synthesis, enabling the production of efficient oxygen-scavenging materials.