Synthesis of cyclic diblock copolymers by interfacial condensation

Abstract

The well-defined α, ω-dibromopropyl polyisoprene- block-polystyrene- block-polyisoprene copolymer was prepared by coupling of corresponding triblock dianion end-capped with 1,2-diphenylethylene with a large excess of 1,3-dibromopropane. End-to-end ring closure of the α, ω-dibromopropyl triblock copolymer was performed by interfacial condensation between the aqueous phase (1,6-diaminohexane) and the organic phase (difunctional triblock copolymer). The limited field of reactions such as at the interface was very effective for ring closure. In the strongly segregated state, the lamellar domain spacing of cyclic diblock copolymer was smaller than that of linear A–B diblock copolymer with the same molecular weight.