Synthesis and characteristics of a novel aliphatic polycarbonate, poly[(propylene oxide)‐ co ‐(carbon dioxide)‐ co ‐(γ‐butyrolactone)]

A novel aliphatic polycarbonate, poly[(propylene oxide)‐ co ‐(carbon dioxide)‐ co ‐(γ‐butyrolactone)] [P(POCO 2 GBL)], was synthesized by the copolymerization of carbon dioxide, propylene oxide (PO) and γ‐butyrolactone (GBL). The resulting copolymers were determined by FTIR and NMR spectral analysis with viscosity‐average molecular weights ( M v ) from 50 000 to 120 000 g mol −1 . According to elemental analysis, the calculated data of elemental contents in P(POCO 2 GBL)44 were close to the found data. The result showed that GBL was inserted into the backbone of poly[(propylene oxide)‐ co ‐(carbon dioxide)] successfully. GBL offered an ester structural unit that gave the copolymer better degradability. The correlations between reaction conditions and properties were studied. When GBL content increased, the M v and the glass transition temperature ( T g ) of the copolymers improved relative to an identical copolymer without GBL. Prolonging the reaction time of the copolymerization resulted in increases in M v and T g . P(POCO 2 GBL) exhibited a high T g above 40 °C. The rate of backbone degradation increased with increasing GBL content.