By: Ms. Sheikhi

Abstract
In this study, starch film and starch/chitosan composite film were modified by a low pressure air and O2 plasma at different durations. The effects of plasma on the topography, wettability, chemical surface composition, mechanical properties, optical properties, oxygen permeability and water vapor permeability of the films
were examined. The mechanical properties of the both films were significantly improved. It is shown that air plasma is more efficient in improving tensile strength of the films due to more crosslinking at the air plasma treated film surface. No significant change in the starch film ҆s elongation at break was observed although
starch/chitosan composite film ҆s elongation at break was increased due to polymer degradation. After plasma treatment the roughness of the treated film surface increased due to etching effects of plasma. A significant increase in the hydrophilicity of the films was observed due to formation of oxygen-containing groups after plasma treatment. FTIR analysis illustrated a decrease in C-H groups
that caused an increase in C-O and COC groups in air treated films and carbonyl groups in O2 –treated films. Although an increase was found in hydrophilic groups on the film surface after plasma treatment, no significant change was observed in WVP of films, however oxygen permeability of the films were decreased.