PET recycled and processed from flakes with different amount of water uptake: characterization by DSC, TG, and FTIR-ATR

Recycled PET from bottles was processed from flakes, which containing different amounts of water uptake. After this process, they are subjected to characterization by differential scanning calorimetry (DSC), thermogravimetry (TG), and Fourier-transform infrared spectroscopy with an attenuated total reflectance accessory (FTIR-ATR). From the DSC and TG results it can be postulate an increase in the proportion of short-molecular-weight distribution in the PET chains, due to the hydrolytic degradation of recycled PET during the thermopressing in presence of water. This hydrolytic degradation probably formed more polar groups on the surface of the processed and recycled PET, like carboxyl groups, as observed by FTIR-ATR.