Migration Analysis Of Compounds From Food Packaging Material

With the development of material science, polymeric materials have been widely applied in food packaging industry with different shapes. However, polymeric materials have specific performance and manufacturing method which resultes in producing lots of free monomers with low molecular weight. And these free monomers bring big hidden trouble for food safety and public health. In order to solve this problem, we should analyze the migration of low-molecular-weight components from polymeric materials and take into account of migration substances in markets before choosing materials.This paper mainly analyzes migration modeling and its influencing factors (diffusion coefficient and partition coefficient). And using current experimental conditions, I measured the migration quantity of components (chlorobenzene and phenol) from PET bottle, then analyze and compare the migration modeling and experimental data. In this paper, monolayer's and two-layers'migration modeling are discussed, including influence of boundary layer's limited conditions, food liquid's dissolving and its mucosity. Diffusion coefficient and partition coefficient play important roles in migration modeling. This paper analyzes the semi-experienced equations and free-volume formulae of diffusion coefficient and the normal liquid modeling and UNIFAC modeling of partition coefficient.Because the PET bottle used in market has few chlorobenzene and phenol, I adopt high-concentration method to advance the components'concentrations. In order to ensure the need of migration experiment's analyzing and not change the property of polymer, I choose 2000ppm as the measuring aim. In this experiment, I use n-hexane, 15% ethanol, 3% acetic acid and water as food simulants. With different migration time from four simulants, I measure the migration quantities of chlorobenzene and phenol from four simulants by using GC and do quantitative analysis by internal standard method (n-pentadecane as internal standard). The result is that the experimental data satisfy Fick migration kinetics charcteristic.