Release of propyl paraben from a polymer coating into water and food simulating solvents for antimicrobial packaging applications

The release phenomena of propyl paraben from a polymer coating to water and three food simulating solvents (10% aqueous ethanol, 50% aqueous ethanol, n-heptane) were studied for antimicrobial packaging applications. The effects of food simulating solvent, initial concentration in the coating and temperature on the propyl paraben release were examined. The initial concentration of propyl paraben in the coating ranged from 1.26 x 10(4) to 10.52 x 10(4) g/m(3) and the temperature from 5.5 to 30C. For water, the release was controlled by Fickian diffusion with constant diffusion coefficient (7 similar to 11 x 10(-11) cm(2)/s at 30C), and independent of the initial concentration For 10% ethanol, the release followed again the Fickian model with constant diffusion coefficient (30 similar to 40 x 10(-11) cm(2)/s at 30C). For 50% ethanol and n-heptane, the release was instantaneous and not controlled by Fickian diffusion. For the release into water the activation energy for diffusion from the Arrhenius relationship was around 88 kJ/mole.