초록 |
The copolymerization of propylene oxide (PO) with carbon dioxide (CO2) catalyzed by double metal cyanide (DMC) catalysts, prepared by reacting aqueous zinc chloride (II) and potassium hexacyanocobaltate (III) with P123 as a co-complexing agent and various complexing agents (CAs) were systematically studied. The CAs used in this study include hydroxyl, ketone, dicarboxylic acid, diester, keto-ester and alkoxy substituted organic compounds. The activity and CO2 selectivity of DMC catalysts depend on the types of CAs. The resultant polycarbonate polyols produced in the presence of poly(propylene glycol) (PPG) starter were analyzed by using FT-IR, NMR, GPC, TGA, DSC, hydroxyl value. The types of CAs also influences the molecular weight and glass transition of polycarbonate polyols. The hydroxyl functionality of polycarbonate polyols is successfully controlled by the type of PPG starter. |