Temperature Dependence of Oxygen Diffusion into Clay-Doped PS Films

Abstract

Fluorescence technique was employed for the measurement of the diffusion coefficient of oxygen into polystyrene (PS) latex/modified Na-activated bentonite (MNaLB) clay composite films. Three different MNaLB content (0 5 and 20 wt%) composite films were prepared from PS/MNaLB mixtures by annealing them at 200 degrees C above the glass transition temperature of PS for 10 min. To determine the diffusivity of oxygen in PS/MNaLB composite films diffusion measurements were performed over the temperature range from 25 to 70 degrees C. Pyrene (P) was used as the fluorescent agent. The diffusion coefficients (D) of oxygen were determined by combining the fluorescence quenching method with Fickian transport model and were found as a function of temperature for each MNaLB content film. The results showed that D values are strongly dependent on both temperature and clay content in composite film. It was also observed that D coefficients obey Arrhenius behavior from where diffusion activation energies were measured. POLYM. COMPOS. 31:77-82 2010. (C) 2009 Society of Plastics Engineers