ABA type triblock copolymer and method for producing the same

摘要

To provide a novel ABA-type triblock copolymer of vinyl ether series, comprising polyvinyl ether and an oxystyrene-series unit, and a process of producing the ABA-type copolymer at a series of steps. The invention relates to a novel ABA-type triblock copolymer comprising Segment A comprising an oxystyrene-series repeat unit (a) and Segment B comprising a vinyl ether-series repeat unit (b), in which the Segment A and the Segment B are bonded together with a single bond, and to a simple process of producing the same. The triblock copolymer can be produced at a series of steps in a simple manner, comprising living cationic polymerization of a vinyl ether-series monomer such as ethyl vinyl ether in the presence of a bifunctional initiator and a Lewis acid, and subsequently adding an oxystyrene-series monomer such as p-hydroxystyrene for living cationic polymerization.