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Abstract
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High density polyethylene (HDPE) films were produced using cast film extrusion process with different
draw ratios, ranging from 16.9 to 148.8. Morphology, crystallinty and orientation state of crystalline and
amorphous phases of the cast films were investigated using scanning electron microscopy (SEM), differential
scanning calorimetry (DSC) and polarized Fourier transform infrared spectroscopy (FTIR) analyses, respectively.
The anisotropic crystalline structures of row-nucleated lamellar morphology were observed for the films produced
with high draw ratios. The crystalline phase axes orientation functions were found to be significantly dependent on
the applied draw ratios. As expected, annealing increased the crystallinity and melting point temperature (Tm) of the
cast films and on the other hand, it also enhanced the crystalline phase orientation. However, the results revealed
that annealing also promoted non-twisted lamellar structures, since it increased the fc values (c-axis orientation
function) and decreased the fa values (a-axis orientation function) simultaneously. Additionally, it was found that
the annealing induced enhancement in c-axis orientation function was more significant for the cast films with lower
draw ratios, therefore, it was dependent on the draw ratio.
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