The FTIR spectrum of metalized surface of PET (side2 – PET metalized) presents only noise in the characteristic PET
absorbing region indicating that its surface is completely covered
by aluminum.
Thermal analysis was employed in order to verify whether the
delamination process influences the stability of polymers. Fig. 2
shows the DSC curves of film and of PE and PET polymers after
delamination. As it could be observed in the DSC curve of film, the
peak at ca. 120 ◦C is related to the melting of polyethylene, which
could be confirmed by the DSC PE curve. This peak has a broad shape
due to the presence of different kinds of polyethylene: linear lowdensity
polyethylene – LLDPE (melting temperature of 109 ◦C) and
low-density polyethylene – LDPE (melting temperature of 118 ◦C).
Therefore, the studied package is composed of PET, aluminum and
a mixture of LLDPE and LDPE. Such mixture (LLDPE/LDPE) is used
because pure LLDPE presents high shear resistance, which makes it
more difficult to be processed than pure LDPE [29]. However, films
made of LLDPE present better mechanical and optical properties
than LDPE. The second peak at 253 ◦C, in the DSC curve relative
to the film, is attributed to melting of PET, also observed in the
DSC PET curve. For temperatures higher than 400 ◦C the polymers
degradation is observed; such temperature range was not changed
by the delamination process, as can be seen in the DSC curves of
pure components. The thermogravimetric analyses (Fig. 3) confirm
the delamination process did not change the thermal properties ofmaterials. The temperature in which the weight loss rate is greatest
for the film and both polymers (after delamination) is ca. 400 ◦C.