Hence the castings of the films were easier in acetic acid, which also exhibited comparatively better barrier properties. Glycerol has some plasticizing effect which promoted the mobility of the chains, thereby making diffusion of oxygen molecules through the film easier. studied the effect of different acid types on barrier properties of chitosan films and observed that inclusion of 1% acetic acid had lower WVP and OTR than that of 1% propionic acid. Oxygen permeability of chitosan films were as low as many conventional plastic films such as polyvinylidene dichloride and ethyl vinyl alcohol.