Nucleophile-initiated and thermal bulk polymerizations of cyclic trimethylene carbonate in the absence of added catalysts

Nucleophiles such as alcohols and diols, water and amines initiate the bulk polymerization of cyclic trimethylene carbonate (TMC, 1,3-dioxan-2-one) at 100–120°C in the absence of added catalysts. TMC is ring-opened by attack of the carbonyl carbon by the lone pair of the oxygen or nitrogen atom of the nucleophilic agent and scission of the acyl-oxygen bond. With diols and water as initiators, the number-average molar mass (Mn) of polyTMCs is controlled, up to 5–6 000, by the monomer/initiator molar ratio. In the case of amines, the residual water present in the monomer, activated by complexation with the amine, participates, from the beginning, in the initiation. The structure of prepared polyTMCs was studied by 1H and 13C NMR spectroscopies. TMC purified by sublimation undergoes “spontaneous” thermal polymerization in bulk at 100–120°C. Quantitative yields and high molar mass polyTMCs could be obtained within 48 h. The structure of polyTMCs and the existence of an early intermolecular transesterification were confirmed by MALDI-TOF mass spectrometry.