Permeability of ethanol solution through poly(lactic acid) film

The permeation properties of ethanol solution through poly(lactic acid) (PLA) films were investigated. The total flux of ethanol solution through PLA films was strongly depended on the flux of water. In addition, the diffusion coefficient of water was 1000 times higher than that of ethanol, and decreased with increasing feed concentration. After the permeation measurement, crystallization (XC-DSC=1-2%) was observed. However, the crystallinity was not dependent on the feed concentration. On the other hand, the mole ratio of ethanol and water molecules in the PLA film strongly depended on the feed concentration. Based on the results, we concluded that the interaction with ethanol molecules caused the decrease in diffusion coefficient of water in PLA film. Thus, the permeation mechanism of the ethanol solution to the PLA film was investigated in detail. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42031.