Preparation of metal chelating active packaging materials by laminated photografting

Active packaging materials with surface immobilized metal chelating ligands were prepared by laminated photografting technique. The resulting materials presented transition metal scavenging properties with potential application in non-migratory antioxidant active packaging materials. Photografting of functional polymer ligands is typically performed in an oxygen-free environment, requiring a nitrogen inerting step, which limits potential industrial scale-up. Laminated photografting eliminates the need for nitrogen inerting by sandwiching the monomer solution between base material and an oxygen barrier layer. In this study, we demonstrated the ability to synthesize metal chelating active packaging materials, previously prepared by standard batch photografting, using a laminated photografting technique. The polypropylene-graft-poly(acrylic acid) and polypropylene-graft-poly(hydroxamic acid) chelating films prepared by laminated photografting presented similar surface chemistry as those reported previously, as characterized by infrared spectroscopy, and presented ferric ion chelating capacity of 182 ± 29 and 89 ± 10 nmol/cm², respectively, at pH 5.0. The reported laminated photografting represents a coating technology with potential for adaptation to roll-to-roll manufacture of metal chelating films on an industrial scale.