Migration of TiO2 from PET/TiO2 Composite Films Used for Polymer-Laminated Steel Cans in Acidic Solution

Abstract

Nano-TiO2 is widely used as a commercial food contact material (FCM), which poses potential risks to food. Therefore, the migration of TiO2 is crucial for the safety of FCM. Since PET/TiO2 composite films are food contact layers used for producing polymer-laminated steel cans and the majority of beverages contained in cans are acidic, it is necessary to study the migration of TiO2 from PET/TiO2 composite films in acidic solutions. The migration of TiO2 in 4% (v/v) acetic acid was studied through the ICP-OES method. The corrosion process that occurred during the migration process was studied using electrochemical impedance spectroscopy (EIS). The morphology of Ti nanoparticles and films was measured by SEM, TEM, and dynamic light scattering (DLS) techniques. The results indicate that, at a temperature of 60 °C, the maximum migration concentration of TiO2 is 0.32 mg/kg. The TiO2 particles released during the migration process are unstable and tend to aggregate in the simulated material, with most of the Ti being present in the form of particles. Therefore, the migration of TiO2 does not follow the Fick law of diffusion but rather conforms to the Weibull model based on the non-Fick law of diffusion.