For the production of I-PET sheet, after the polymer is melted in the extruder, it is shaped while it is in the molten state (T-285 C), immersed in a water bath with an average temperature of 7 C and cooled.

a) A sample taken from this film is then kept at T-210 C for 1 hour and then cooled to room temperature at a rate of 5 C/min.

b) The sample taken from this film is immersed in ethylene glycol (EG) and the EG is absorbed at room temperature for 24 hours (no chemical change occurs).

For these PET samples, plot the DSC selling thermograms that will be obtained immediately after production, immediately after the process specified in (a), and immediately after the process specified in (b) (on the same DSC thermogram). Discuss the differences that occur. (For pure PET; T, -65 C, T.-145 C and T-268C)