Polymerisation of trimethylene carbonate (TMC) and its copolymerisation with L-lactide (LA) using the SmI2/Sm initiator system is reported. The reactions were carried out at different temperatures to optimize the reaction conditions. Reactivity ratio values evaluated using the Kelen-Tiidos method were 7.24 and 0.25 for LA and TMC, respectively. Microstructure of the copolymers and its change with the reaction time is reported using 1D (H-1 and C-13) and 2D heteronuclear multiple-bond correlation NMR spectroscopic techniques. Electrospinning of the resulting copolymers was tried for the generation of fibres. Drastic deviations of the thermodynamic state from equilibrium were seen in the first heating cycle of the DSC trace of the electrospun fibres and are also reported here. (c) 2005 Society of Chemical Industry.