Preparation and characterization of chitosan/poly(vinyl alcohol) composite packaging films

A novel chitosan/poly(vinyl alcohol) composite packaging films were prepared by the casting method, and the effects of chitosan concentration on the structures, mechanical properties, permeability for oxygen and water vapor were discussed in this study. Mechanical properties of these films, which were evaluated by the tensile test and the barrier properties showed that the elongation at break (E) of the composite films decreased rapidly with the addition of chitosan, whereas, the tensile strength (TS) presented an almost opposite trend. Both the water vapour and oxygen transmission rate values were increased with the increasing amount of the chitosan in the composite films. Based on the obtained results, the better property of the composites films would be prepared chitosan/poly(vinyl alcohol) blends at a weight ratio of 3/5, and the tensile strength and elongation at break of the packaging films were 34.12 MPa, 40.24% respectively. It was also observed that the water vapor permeability coefficient (P-v) and the oxygen permeability coefficient (P) of chitosan/poly(vinyl alcohol) composite packaging films prepared with weight ratio of 3/5 were 1.99x10(-15) g.cm/cm(2).s.Pa and 7.98x10(-16) cm(3).cm/cm(2).s.Pa respectively. The composite films in this paper can be used in fresh-keeping or other fields as a kind of green packaging material.