Comparative Numerical Study of Titanium and Silver Nano-particles Migration from Nano-composite of Polystyrene into Simulants on Experimental Data Basis

Nano-titanium dioxide and nano-silver combined with polystyrene granules to form a nano-composite film. Migration assess were performed by using food simulants 3% acetic acid (indicative acidic food) and 95% ethanol (indicative fatty food) at 40°C on different times of 2, 4, 6, 8 and 10 days. It was found that nanoparticle migration rate in acidic food was higher than fatty food. Diffusion coefficients of nanoparticles into simulants were estimated by inverse simulation of the migration process using finite-element method and experimental data of varied concentration. Simulation revealed an acceptable consistency between experimental data and predicted values. The numerical results indicated that the greatest diffusion coefficient was obtained by nano-titanium (2.8E-10 to 4.1E-9 m s ) in the 3% acetic acid. Results of concentration distribution confirmed a higher release rate and more uniformed distribution of nanoparticles for nano-titanium in the 3% acetic acid. It also found that in the migration process the diffusion coefficient is more important than the amount of nanoparticles concentration.