| Abstract |
The copolymerisation of epsilon-caprolactone (epsilon-CL) and trimethylene carbonate (TMC) catalysed by methanesulfonic acid was investigated. Preliminary copolymerisation tests using a monofunctional initiator confirm that the side bidirectional propagation previously detected in the homopolymerisation of TMC is also present in the copolymerisation. The comonomers in the a-CL/TMC system do not follow first order kinetics. The values of the reactivity ratios obtained by the Kellen-Tficlos method (r(epsilon-CL) = 2.90; r(TMC) = 0.62) suggest that random copolymerisation can be achieved, although the copolymer will be richer in epsilon-CL. Dihydroxyl-telechelic epsilon-CL/TMC random copolymers were prepared using a bifunctional initiator. H-1 and C-13 NMR, SEC and DSC measurements show that the poly(TMC-co-epsilon-CL) samples presented the expected microstructural characteristics, a unimodal molarmass distribution and a very narrow polydispersity. Based on these features a novel route for the preparation of block copolyesters with tuned properties, and highly regarded in the development of materials for biomedicine, may be foreseen. (C) 2013 Elsevier Ltd. All rights reserved. |
