The changes in the chemical structure of the co-polymers before and after degradation were also evaluated by the infrared spectroscopy in the attenuated total reflection mode (FTIR-ATR). To obtain ATR-FTIR, a Bruker Alpha spectrophotometer (Bruker Optik, Ettlingen, Germany) was used. The samples were prepared as 100 µm thick films and the spectra were recorded over the range of 400 to 4000 cm-1 at a resolution of 2 cm -1 with 32 scans.