Water vapor transmission rates and sorption behavior of chitosan films

This study measured the water vapor transmission rates (WVTR) and moisture sorption of chitosan films over a range of water vapor pressures at 25 degr eesC. Films of a constant thickness were made using chitosan with 3 levels of deacetylation. Films were tested at test relative humidity (RH) differen ce between RH values of 84%, 75%, 69%, 53%, 43%, 33%, 23%, 11%, and 0 at 25 degreesC using ASTM F1249-90 or ASTM E 96-80. The equilibrium moisture con tent in the films ranged from 3.1% to 31.8% (dry basis) corresponding to 11 % to 84% RH, WVTRs of films increased with increase in water vapor pressure . The mean WVTR ranged from 6.7 to 1146 (g/m(2)/d) over the range of water vapor pressure from 2.68 (11% RH) to 19.9 mmHg (84% RH). The percentage of deacetylation of chitosan films and the viscosity of the cast solution did not have an effect on the WVTR properties of chitosan films.