Oxygen permeability coefficients (OP), water vapor permeability coefficients (WVP), ethylene permeability coefficients (EP), tensile strength (TS) and percent elongation (%E) at break values were determined for chitosan films plasticized with glycerin at two concentrations (0.25 and 0.50 mL/g chitosan). Film samples were tested after 0, 2, 4, 8 and 12 wk of storage. After an initial drop in permeability during the first 2 wk of storage, mean OP (4.6 ϫ 10 Ϫ5 cc/m⅐day⅐atm) and mean EP (2.3 ϫ 10 Ϫ4 cc⅐/m⅐day⅐atm) remained constant while mean WVP (2.2 ϫ 10 Ϫ1 g/m⅐day⅐atm) decreased with respect to storage time. TS values (15-30 MPa) decreased and %E values (25%-45%) increased with respect to storage time. The stability of OP and EP values with storage was not expected, while the change in mechanical properties was as expected.
This study measured the water vapor transmission rates (WVTR) and moisture sorption of chitosan films over a range of water vapor pressures at 25°C. Films of a constant thickness were made using chitosan with 3 levels of deacetylation. Films were tested at test relative humidity (RH) difference between RH values of 84%, 75%, 69%, 53%, 43%, 33%, 23%, 11%, and 0 at 25°C using ASTM F1249-90 or ASTM E 96-80. The equilibrium moisture content in the films ranged from 3.7% 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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.