The chemical structure of the copolymers before and after degradation was analyzed using proton nuclear magnetic resonance ( 1 H NMR) spectroscopy. To prepare the samples for analysis, the copolymers were dissolved in deuterated chloroform at a concentration of 40 mg/mL and allowed to soak overnight. The solution was then filtered through a pipette fitted with cotton wool on the tip. The NMR spectra were recorded using a Bruker DPX 400 spectrometer (400 MHz) with 128 scans and a 1 s relaxation delay.