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.