Microwave-assisted ring-opening polymerization (MROP) of trimethylene carbonate (TMC) was carried out with four different types of zinc lactate, as the catalyst. Poly(trimethylene carbonate)s (PTMC) with a number-average molar mass ranging from 2990 to 75,410 g/mol and a TMC conversion ranging from 85.2% to 98.2% were synthesized effectively in 30 min at 120 degrees C under microwave irradiation. The effects of the catalyst type, catalyst concentration, and microwave irradiation time on the MROP of TMc were studied. The MROP of TMC was much faster that under conventional heating conditions. Thermal analysis suggested that PTMC with higher molar mass exhibited higher glass trtansition temperature (T-g) and thermal stability. (c) Wiley Periodicals, Inc.