Method of preparing lactone block copolymers

A method of preparing a lactone copolymer which comprises the steps of:

• (a) providing a lithium-terminated polymer of the form A--D--Li).sub.y wherein A is a polymer segment comprising one or more polymer blocks of one or more conjugated dienes and/or monovinylarenes, D is a polymer segment comprising one or more polymer blocks of one or more lactones, and y is 1, 2, 3 or 4, the lithium-terminated polymer being present in a diluent selected from the group consisting of paraffins, cycloparaffins and aromatic hydrocarbons;
• (b) contacting the lithium-terminated polymer with water to form (1) a lactone copolymer of the form A--D).sub.y which is present in an organic phase comprising the lactone copolymer A--D).sub.y and the diluent and (2) a water-soluble lithium hydroxide termination product which is present in a separate phase from the organic phase, the separate phase comprising water and lithium hydroxide;
• and
• (c) recovering the lactone copolymer of the form A--D).sub.y.