THE EFFECTS OF SOLUTION COMPOSITION AND DRYING TEMPERATURE ON CRYSTALLINITY, PERMEABILITY AND MECHANICAL-PROPERTIES OF METHYLCELLULOSE FILMS

The effects of film drying temperature (100C for 35 min, 80C for 1 h, 50C for 1.5 h or room temperature overnight) and ethanol concentration (0, 25, 50 or 75%) in the aqueous film solution on the physical properties of methylcellulose (MC) films were investigated. Increased drying temperatures increased crystallinity in all films. MC films prepared from a 75% water-25% ethanol solvent exhibited smaller permeabilities to oxygen and water vapor, greater crystallinity (when the higher drying temperatures were used), greater tensile strength, and greater percent elongation than films prepared from other water or water/ethanol solvents. Ethanol, at a 25% concentration, may enhance intermolecular hydrogen bonding of MC, while higher concentrations of ethanol may have prevented complete hydration of MC. Extensive association of MC by hydrogen bonding and hydrophobic association (which induces crystallization) likely reinforces the film matrix and presumably produces a film with greater resistance to oxygen and water vapor.