Degradation of polylactide using basic ionic liquid imidazolium acetates

Imidazolium acetate ionic liquids show high efficiency in the degradation of polylactides (PLA): degradation degree of PLA can reach almost 100 % in imidazolium acetate ionic liquids at 170°C and 1 h under atmospheric pressure, while the degradation degree of PLA remains close to 0 % using neutral 1-butyl-3-methylimidazolium tetrafluoroborate (Bmim]BF4) and acidic ionic liquids at the same reaction conditions. With the increase of both the amount of acetate ionic liquid and the reaction temperature, the degradation degree of PLA increases. The structure of ionic liquids affects the degradation behavior of PLA: for cations, the proton from the C-2 position on the imidazolium ring is involved in the degradation of PLA; the degradation of PLA increases with the increase of the alkyl side-chain length of imidazolium cations; for anions, moderate basicity of the acetate ion contributes to the high activity of the imidazolium acetate ionic liquids in the degradation of PLA.