Determination of the mass transport properties of chemical additives in polypropylene material/simulated food system

摘要

The mass transport process (migration) of five additives from three different types of polypropylene (PP) films into selected food simulants was studied. The migration tests were carried out at different time-temperature conditions, and the concentration of additives in polymer matrix and food simulants were analysed by high-performance liquid chromatography (HPLC). With all data, the mass transport properties for migration kinetics (partition and diffusion coefficients) were determined. Results showed that the partition coefficient was affected significantly by the temperature and simulants' properties, whereas little affected by the types of PP film and molecular weight of substance. The polarity, structure and shape of substances can also have an influence in their partition between the polymer matrix and food simulants. Additionally, comparison results between the experimental diffusion coefficients and the calculated values by Piringer model suggested that the current migration model with the default modelling parameters for PP does not describe realistically the diffusion coefficients of additives. The calculated diffusion coefficients were greater than the experimental values, as a consequence, the migration of chemical additives will be overestimated. For more realistic migration calculations, more accurate modelling parameters in Piringer model should be established and the effect of food on migration should be high interest in future work.