Synthesis of styrene and tetrahydrofuran block copolymers by in situ transformation

In order to transfer the halogen terminus of polymers for block copolymer s ynthesis, the in situ transformation of living free radical polymerization of styrene into living cationic ring-opening polymerization of tetrahydrofu ran was successfully performed. Three different initiator/catalyst systems of styrene were employed, i.e. (a) PhCH2Cl/Bpy/CuCl, (b) 1-PEBr/Bpy/CuCl an d (c) CCl4/BDE/CuCl system. With these monofunctional initiator or difuncti onal initiator, both AB and ABA type block copolymers of styrene and tetrah ydrofuran were obtained using a silver salt with strong acid (AgClO4) as th e transformation agent in the transformation of polymerization type. Charac terization of these copolymers by nuclear magnetic resonance hydrogen spect ra (H-1-NMR), gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) indicated this method is simple and feasible.