Synthesis and enzymatic degradation of poly(ε-caprolactone-co-ethylene carbonate-co-ethylene oxide) copolymer

Poly(epsilon-caprolactone-co-ethylene carbonate-co-ethylene oxide) (CL-co-EC-co-EO) copolymer was synthesized via ring-opening copolymerization of epsilon-caprolactone (CL) and 1,3-dioxolan-2-one with a metal-free phosphazene catalyst (t-BuP4). The monomer conversion and molecular weight in CL-co-EC-co-EO copolymer were characterized by nuclear magnetic resonance and gel permeation chromatography, respectively. Moreover crystallization behavior of CL-co-EC-co-EO copolymer was investigated by differential scanning calorimeter and wide-angle X-ray diffraction. The enzymatic degradation of the copolymer has been investigated by quartz crystal microbalance with dissipation. Our studies demonstrate that as PCL content in the copolymer decreases, the degree of crystallinity and crystal size decrease, while the enzymatic degradation rate increases. The copolymer exhibits layer-by-layer degradation.