Isocyanate-free Route to Starch-graft-Polycaprolactone via Carbonyldiimidazole (CDI)-mediated End Group Conversion

This paper reports on the synthesis of biodegradable starch-graft-poly ε-caprolactone (starch-g-PCL) in two steps. First, poly ε-caprolactone (PCL) was modified on the terminal groups by using carbodiimidazole (CDI) as coupling agent. Then, the starch graft copolymers with PCL were prepared through a carbonate bond using carboimidazole function. Monofunctional and bifunctional reactive end-group PCL terminated with carboimidazole groups were prepared and reacted with hydroxyl groups of starch. The resulting starch-g-PCL copolymers were characterized by FT-IR, NMR, HR-MAS-NMR, DSC, MEB and XRD.