Metal chelating materials have a wide range of applications, such as water treatment, protein separation, catalytic chemistry, and active food packaging. Metal-chelating active packaging technology offers a ‘clean label’ alternative to synthetic metal chelators to control transition metal induced oxidative spoilage in consumer products. Prior proof of principle research established the efficacy of polymer film bound metal chelators in binding iron and preventing oxidation, yet there remain technological hurdles preventing the commercial translatability of such active packaging. In this project, we synthesized a photo-curable metal-chelating copolymer coating to enable a simple coat/cure preparation of metal chelating active packaging materials. The copolymer coating was composed of an iminodiacetic acid: n-butyl acrylate: benzophenone (2:79:19) copolymer, imparting chelating, low surface energy, and photo-curable functionality, respectively, and was synthesized by emulsion polymerization of n-butyl acrylate and functional vinyl monomers. The copolymer was applied onto polypropylene films and was photo-cured (365 nm, 225 mW/cm2, 180s) in laboratory to produce metal chelating film. Cross-linking reaction of benzophenone moieties was monitored by following the absorption band at 270 nm during the photo-curing process. The resulting film exhibited chelating capacities of 10.9 ± 1.9 nmol/cm2, 47.9 ± 5.3 nmol/cm2, and 156.0 ± 13.8 nmol/cm2 of Fe3+ at pH 3.0, pH 4.0, and pH 5.0, respectively. The metal-chelating film had antioxidant efficacy against transition metal induced ascorbic acid degradation. Tailoring the synthesis and chemistry of photo-curable polymer coatings as reported here enables scalable production of active food packaging materials with targeted surface energy and functionality.

Preparation of photo-curable metal-chelating copolymer coatings for antioxidant active packaging

256th National Meeting (2018)

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