Chitosan Film Mechanical and Permeation Properties as Affected by Acid, Plasticizer, and Storage

Abstract

ABSTRACT The effects of acid (acetic, formic, lactic, propionic) concentrations, plasticizer concentrations, and storage time (up to 9 wk) on mechanical properties, water vapor permeability, and oxygen permeability of solution‐cast chitosan films were determined. Measured water vapor permeability coefficients ranged from 5.35 to 13.20 × 10 −1 g/m·day·atm. Oxygen permeated coefficients ranged from 0.08 to 31.67 × 10 −3 cc O 2 m·day·atm. Neither property was affected by storage time. Tensile strength (6.85–31.88 Mpa) also was not time dependent, but elongation (14–70%) decreased with storage time. Lactic acid solutions produced the lowest oxygen permeability values, formic acid the highest. Films formed with 7.5% lactic acid solutions had uniquely high values for elongation at break.