Polymerization of epsilon-caprolactone initiated by Y alkoxide grafted onto porous silica

Ring-opening polymerization of c-caprolactone has been initiated by Y isopropoxide grafted onto silica, in the presence of 2-propanol, in toluene at 40degreesC. The degree of polymerization is controlled by the initial monomer/(alcohol + alkoxide) molar ratio. Deactivation of the chains by an alcohol is essential for them to be detached from the support and to be collected totally free of metal and silica residues. The alkoxide is also regenerated at the surface of the support, which allows for recycling the catalyst.