Synthesis of Poly[(ethylene carbonate)-co-(ethylene oxide)] Copolymer by Phosphazene-Catalyzed ROP

Poly[(ethylene carbonate)- co -(ethylene oxide)] is synthesized by ROP of 1,3-dioxolan-2-one using 1- tert -butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)phosphoranylidenamino]-2Λ5,Λ5-catenadiphosphazene as the catalyst. NMR spectroscopy shows that the copolymer chain consists of EO-EC-EO-EO sequences. GPC measurements indicate a PDI of 1.43–1.66 and show that the molecular weight increases with monomer conversion. Thermal analysis demonstrates that the copolymer is amorphous with a glass transition temperature of about –42 °C and an onset decomposition temperature of about 200 °C.