Ultraviolet-cured p-phenylenediamine functionalized polypropylene film as a non-migratory antioxidant

Abstract

Ultraviolet (UV) induced modification is a simple technique to render the interface of inert materials into a functional property. In this study, a curable copolymer coating was synthesized using glycidyl methacrylate and 4–benzoylphenyl methacrylate via atom transfer radical copolymerization. Butyl acrylate was also introduced to the copolymer, which in turn improved the ductility and facilitated the surface modification using copolymer with bulky groups. The chemical structure of this copolymer was identified using 1H NMR and FTIR. Accordingly, the monomers in the feed were also observed in the copolymer backbone. Ultraviolet (UV) cure potency of the copolymer was monitored using UV–visible spectroscopy in which 90 s UV–irradiation (365 nm) enabled one-step functionalization of polypropylene (PP) surface. Additionally, the existence of the pendant oxirane ring of copolymer on the PP surface after coating assisted in the immobilization of p–phenylenediamine, which realized antioxidant film. The oxidation and reduction abilities of the antioxidant film were assessed using cyclic voltammetry, supporting the free radical scavenging ability of the film. This antioxidant film remarkably (p < 0.05) delayed the lag time of vitamin C degradation and olive oil oxidation. Moreover, the antioxidant film did not leave any migrant behind after incubation with simulant solvents, showing a non-migratory feature. Therefore, this non-migratory antioxidant film can be practically applied in packaging, cosmetic, and biomedical fields.