Migration of phthalates from polyvinyl chloride film to fatty food simulants: experimental studies and model application

Phthalates (PAEs) are used as plasticizer for producing food contact materials. However, PAEs can contaminate foodstuff through chemical migration and present serious environmental concerns. This study aims to investigate the migration of five common PAEs (diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, butyl benzyl phthalate, and di(2-ethylhexyl)phthalate) from polyvinyl chloride into fatty food simulants (n-hexane, isooctane, and 95% ethanol). The migration levels of the five PAEs into different food simulants were compared after reaching equilibrium with the plastic additive. The migration rate was higher when the molar mass was lower, whereas K-o/w and the migration temperature were higher. Key parameters (diffusion and partition coefficients) of the migration processes were calculated and compared at different temperatures using a mathematical model based on Fick's second law. The diffusion coefficients ranged from 1.08 x 10(-11) cm(2)/s to 5.50 x 10(-10) cm(2)/s at 60 degrees C, 2.46 x 10(-13) cm(2)/s to 3.61 x 10(-11) cm(2)/s at 40 degrees C, and 8.30 x 10(-14) cm(2)/s to 3.60 x 10(-12) cm(2)/s at 20 degrees C. The diffusion coefficients well fit the Arrhenius relationship in the range of 20-60 degrees C.