The synthesis of poly(trimethylene carbonate) via carbene catalyzed ring-opening polymerization (ROP) was investigated. The N-heterocyclic carbenes were protected as CO2-adducts to improve their handling (e.g., carbene generation without base). The influence of catalyst structure, different solvents and microwave radiation on conversion, molecular weight and end groups was investigated to gain an insight into the reaction mechanism. Different NHC structures were investigated for their catalytic activity toward the ROP of trimethylene carbonate. The analytic studies were performed by using NMR spectroscopy, SEC and ESI-IMS mass spectrometry. It was found that the reaction can be performed in acetonitrile, toluene, THF and CH2Cl2. Synthesis in CH2Cl2 allows the best control over the resulting polymer with regards to polydispersity and molecular weight. Microwave radiation accelerates the reaction at 80 degrees C. (C) 2016 Wiley Periodicals, Inc.