Water vapor permeability and mechanical properties of chitosan composite films

Chitosan films or membranes can be obtained by casting chitosan solutions in acetic acid at 1% w/v concentration at room temperature. The films set were elaborated from 2% chitosan solutions mixed with three plasticizers (Polyethylene glycol 200 (PEG), sorbitol and glycerol) and two surfactants (Tween 60 and Tween 80) at two concentrations. The goal was to decrease the water vapor permeability and to improve the mechanical properties of chitosan films. The effects of plasticizers (PEG, sorbitol and glycerol) and emulsifiers (Tween 60 and Tween 80) at two concentrations from chitosan solution on water vapor permeability and mechanical properties of cast films were evaluated. Water vapor permeability ranged from 3.64 to 6.56 g mm/h m(2) KPa., tension force from 7.23 to 48.3 MPa and elongation percentage from 22.9 to 167.02 were obtained. Chitosan two percent with 0.3% Tween 80 produces films that showed the lowest permeability value. Chitosan with 0.6% glycerol has the highest percentaje of elongation, being 4.5 times higher than chitosan films. Chitosan with 0.6% Tween 80 improved the hydrophobicity of the chitosan film in 1.14 times. The highest value for tension force was found for chitosan with 0.6% of Tween 60. These values are similar to some polymers based on mineral oil