Abstract:In order to solve the problem that trace transition metal ions can catalyze the oxidation of food, acrylic acid (AA) was grafted onto the surface of PP film by ultraviolet surface grafting technology to prepare PP-g-PAA film. The PP-g-PAA film could restrain oxidation with metal ion chelating ability. The structure and morphology of the film were characterized by FT-IR, SEM and metallographic microscope. The results show that a dense and uniform poly(acrylic acid) (PAA) grafting layer on the PP-g-PAA film is obtained. Different carboxyl density can be obtained by controlling the grafting time. The carboxyl group density, Cu2+ chelating amount and the ratio of the two were studied by dyeing method and atomic absorption spectrometry. When the carboxyl group density of PP-g-PAA film is less than 4.24 μmol/cm2, the ratio of the carboxyl group to the Cu2+ chelating amount is about 4, indicating that they can form a stable five-membered ring chelating structure to inhibit the catalytic oxidation of metal ion. The effect of UV grafting reaction on the mechanical properties and barrier properties of the film was investigated, when the grafting time reaches 20 min, the elongation at break of the film is drastically reduced, but the oxygen barrier performance is significantly improved.