The compression molding of PEFA resulted in flexible and translucent films (Figure ). The initial step of the film synthesis was a thermal treatment for 3 h and 15 min at 150 °C. The duration was designed to carry out the melt polycondensation reaction and obtain a sample that would still melt in the following pressing stage to generate a homogeneous film. The sample strongly adhered to the Teflon sheets used in the thermoforming process, and could only be removed without damage after 5 days. We hypothesize that the cross-linking reaction slowly continues over the 5 days, during a curing phase, since the glass transition temperature (Tg) was below room temperature of the polyester (thermal properties discussed later in this paragraph). The removal of one of the Teflon sheets was necessary to prevent the film from losing its shape during final curing, where the polymer would still partially melt and diffuse unevenly if left between the sheets. The 10 h duration of the curing step was chosen to eliminate the stickiness of the PEFA film, observed after shorter curing times. The esterification reaction was monitored using FT-IR spectroscopy (Figure ). After 3 h and 15 min of melt polycondensation, the rising band at 1733 cm -1 confirmed successful esterification, while a noticeable band at 1714 cm -1 indicated nonesterified carboxyl groups. Following the curing step, the intensity of the PEFA film's ester band grew stronger, showing that the reaction had progressed even further. However, the signal from unreacted carboxyl groups remained (Figure ). The epoxide band at 846 cm -1 disappeared upon the initial thermal treatment while the intensity of the hydroxyl band (3100-3600 cm -1 ) progressively decreased during the process and showed a shift towards higher wavenumbers. These findings are consistent respectively with the consumption of the