Simulating diffusion model and determining diffusivity of potassium sorbate through plastics to develop antimicrobial packaging films

A diffusion model was simulated by computer programming and diffusivities of potassium sorbate through various plastic films were determined by a lag time method. The simulation showed that partition coefficient affected the flux of total penetration but did not affect the lag time, Therefore, the lag time method is appropriate in determining diffusivity, using any value for the partition coefficient. The diffusivities of potassium sorbate were 1.83 x 10(-8) cm(2)/s, 4.26 x 1(0-13) cm(2)/s, 4.65 x 10(-13) cm(2)/s, and 5.47 x 10(-13) cm2/s through low density polyethylene (LDPE), high density polyethylene, polypropylene, and polyethylene terephthalate, respectively at 25C. Arrhenius equation shows very good fit between the diffusivity and the temperature by the linear regression analysis. D-o and E-a of potassium sorbate through LDPE film resulted in 1.98 x 10(-6) cm(2)/s, and 11.83 KJ/mole K. The concentration of potassium sorbate was insignificant and did not contribute to the statistical model. This result verifies that the diffusion of potassium sorbate in LDPE film is typical case of Fickian diffusion.