Effect of clay content, homogenization RPM, pH, and ultrasonication on mechanical and barrier properties of fish gelatin/montmorillonite nanocomposite films

The effect of clay content, homogenization RPM, and pH on the mechanical and barrier properties of fish gelatin/nanoclay composite films was investigated. The addition of 5% nanoclay (w/w) increased the tensile strength from 30.31 +/- 2.37 MPa to 40.71 +/- 3.30 MPa. The 9 g clay/100 g gelatin film exhibited the largest improvements in oxygen and water barrier properties. Oxygen permeability decreased from 402.8 x 10(-6) 0.7 x 10(-6) g m/m(2) dayatm to 114.4 x 10(-6) +/- 16.2 x 10(-6) g m/m(2) day atm and the water vapor permeability decreased from 31.2 X 10(-3) +/- 1.6 x 10(-3) ng m/m(2) s Pa to 8.1 X 10(-3) +/- 0.1 X 10(-3) ng m/m(2) s Pa. The XRD and TEM observation suggested that the ultrasonication treatment (30 min at 40% output) resulted in exfoliation of the silicates. (C) 2008 Published by Elsevier Ltd.