Morphology and mechanical property relationship in linear low-density polyethylene blown films

Linear low-density polyethylene (LLDPE) blown films fabricated under two different processing conditions, namely a non-stalk bubble configuration and a stalk bubble configuration, were investigated. Morphological characterization was performed using small-angle X-ray scattering, transmission electron microscopy, infrared dichroism, and differential scanning calorimetry. The findings on crystal orientation characteristics of the films suggest that modification on the widely accepted row orientation model of Keller and Machin may be needed. In comparison to the conventional non-stalk bubble geometry for LLDPE film blowing, the stalk bubble configuration can produce a more randomly orientated lamellar texture, resulting in less anisotropy in mechanical properties and a higher dart impact resistance. A good correlation between mechanical properties and morphological features was found. (C) 2000 Kluwer Academic Publishers.