The effect of composition and draw-down ratio on morphology and oxygen permeability of polypropylene nanocomposite blown films

Polypropylene nanocomposite blown films containing organoclay were prepared by melt extrusion followed by film blowing. The effect of quantity of organically modified montmorillonite, and the compatibilizer (polypropylene-g-maleic anhydride, PP-g-MA), also the draw-down ratio on the morphology and oxygen permeability of nanocomposite films were investigated. Various characterization instruments were employed to identify the morphology, crystallinity, and dynamic mechanical properties of nanocomposite films. The oxygen permeability coefficient was evaluated based on ASTM D 1434. X-Ray diffractometry pattern for the most impermeable sample shows that the morphology of nanocomposite film is a coexistence of intercalated tactoids and exfoliated layers which is confirmed by transmission electron microscope micrographs. The results show that the oxygen permeability coefficient is influenced by the quantity of organoclay and compatibilizer, also the morphology and orientation of layered silicate. (C) 2007 Elsevier Ltd. All rights reserved.