Hydrophilicity, Solubility and Optical Properties in Composite Films of Gelatin and Bentonite Clay in its Natural Form or Modified

Bentonite clay was initially treated with a quaternary ammonium salt to increase its hydrophobicity, and then was dispersed in a gelatin matrix to serve as barrier to water vapor. The clays were characterized by IR spectroscopy in the infrared (FTIR), and X-ray diffraction (XRD), before and after ion exchange. The ion exchange held in the clay provokes on gelatin film a reduction of 65% in the water vapor permeability (WVP); a decrease in solubility of 55%; an increase of 35º in drop contact angle of water on the surface of the film; and 30% of raise in opacity.