Chitosan film mechanical and permeation properties as affected by acid, plasticizer, and storage

The effects of acid (acetic, formic, lactic, propionic) concentrations, pla sticizer concentrations, and storage time (up to 9 wk) on mechanical proper ties, water vapor permeability, and oxygen permeability of solution-cast ch itosan films were determined. Measured water vapor permeability coefficient s ranged from 5.35 to 13.20 x 10(-1) g/m.day.atm. Oxygen permeated coeffici ents ranged from 0.08 to 31.67 x 10(-3) cc O-2/ m.day.atm. Neither property was affected by storage time. Tensile strength (6.85-31.88 Mpa) also was n ot time dependent, but elongation (14-70%) decreased with storage time. Lac tic acid solutions produced the lowest oxygen permeability values, formic a cid the highest. Films formed with 7.5% lactic acid solutions had uniquely high values for elongation at break.