Copolymerisation of ε-caprolactone and trimethylene carbonate catalysed by methanesulfonic acid

Abstract The copolymerisation of e-caprolactone (e-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 e-CL/TMC system do not follow first order kinetics. The values of the reactivity ratios obtained by the Kellen–Tudos method ( r e-CL  = 2.90; r TMC  = 0.62) suggest that random copolymerisation can be achieved, although the copolymer will be richer in e-CL. Dihydroxyl-telechelic e-CL/ TMC random copolymers were prepared using a bifunctional initiator. 1 H and 13 C NMR, SEC and DSC measurements show that the poly(TMC- co -e-CL) samples presented the expected microstructural characteristics, a unimodal molar-mass 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.