Abstract: Functionalized poly(ethylene glycol) methyl ether end capped with fivemembered cyclic carbonate (mPEGGC) was synthesized from mPEG, succinic anhydride and glycerol1,2carbonate. Reaction rate constants and activation energy were determined from the model reaction between mPEGGC and amines at different temperatures. The carbonate conversion increased with the reaction time, amine dosage and temperature, while showed a maximum upon increasing the reactant concentration. The activation energy (Ea) in the reaction of mPEGGC with heptyl amine is the lowest(5.63 kJ/mol). The reaction rate constant for mPEGGC with cyclohexyl amine is larger than that with 2aminoheptane at the same temperature.