Analysis of permeability of low density polyethylene/clay nanocomposite films

Abstract

The goals of this research were two folds, (i) to study the effects of loading of organoclay and compatibilizer on the permeability of LDPE/PE-g-MA/Org-MMT nanocomposite films, and (ii) to verify the applicability of the modified Nielsen model on prediction of permeability LDPE/PE-g-MA/Org-MIMT nanocomposite films. The LDPE/PE-g-MA/Org-MMT nanocomposites were prepared in the twin screw extruder in three-step mixing procedure and the blown into films. Gallery spacing between clay platelets of the Org-MMT and nanocomposite films were measured by X-ray diffraction. Transmission Electron Microscope (TEM) was used to study the distribution of clays in nanocomposite films. The Oxygen Transmission Rate (OTR) of the nanocomposite films were measured by the Oxygen Permeation Analyzer. The experimental permeability data were fitted by the modified Nielsen model. The experimental results showed that the nanocomposite films of LDPE with Org-MMT and PE-g-MA as compatibilizer having lower oxygen permeability properties than pure LDPE film can be obtained by melt mixing. The obtained LDPE/PE-g-MA/Org-MMT nanocomposite films were mainly the intercalated type. The oxygen gas permeability was reduced by about 50% at 3.14-5.09 wt% inorganic clay loading. The transparency of nanocomposite films slightly decreased with increasing clay content. The 9 wt% PE-g-MA was the optimum loading found. The modified Nielsen model can be used to predict the relative permeability of nanocomposite films providing that the aspect ratio, orientation angle, and volume fraction of inorganic clay could be found accurately.