This paper describes a new synthetic route to poly-epsilon -caprolactone. A new cationic polymerisation has been developed which uses a borontrifluoride catalyst to open the caprolactone monomer, and glycerol to increase the molecular weights of the products. A post-treatment method has also been developed to reduce the amount of residual catalyst in the final product. This reduces the extent of borontrifluoride catalysed hydrolysis and therefore allows variation of the degradation rate of the material. (C) 2001 Elsevier Science Ltd. All rights reserved.