The Tg of the system
• The Tg of the pure PET
Fig. 4 shown the computed density as a function of temperature for the pure polymer phase. The procedure to determine the Tg was demonstrated in a first rough estimate of the kink position, which was obtained by visual inspection of the data points. Then, these points were divided into two parts corresponding to the region below (glassy) and above (rubbery) of this estimate The final value of Tg was resulted from the intersection of these two lines. The curve of density vs. temperature for the bulk PET shown a distinct break characteristic of vitrification. The calculated Tg was about 357.2 K.