In a 5-mL vial, 10 mg of purified copolymer was dissolved in 0.5 mL of THF, followed by addition of 0.5 mL of potassium hydroxide solution (KOH, 5 wt %) in MeOH. The cloudy mixture was stirred at room temperature. Samples were collected and dried overnight under vacuum, followed by addition of 2 mL of chloroform and three washes with HCl (1 mL, 1 mol.L -1 ). After extraction, the organic phase was filtered with 0.2 μm PTFE filter and dried under reduced pressure. The degradation products were analyzed by SEC.