FORMATION OF BLOCK-COPOLYMERS BY TRANSFORMATION OF CATIONIC RING-OPENING POLYMERIZATION TO ATOM-TRANSFER RADICAL POLYMERIZATION (ATRP)

Transformation of cationic ring-opening polymerization to atom transfe r radical polymerization (ATRP) to form AB and ABA type block copolyme rs was performed. Syntheses of AB type block copolymers initiated by p olyTHF (poly(tetramethylene glycol)) containing one bromopropionyl end group were successful for styrene, methyl methacrylate (MMA), and met hyl acrylate (MA). Block copolymers were characterized by GPC, H-1 NMR spectroscopy, and thermal analysis (DSC). An ABA type triblock copoly mer formed from a telechelic bifunctional polyTHF backbone that contai ned bromopropionyl groups at both ends was clearly formed in the case of successive ATRP of MMA. The triblock copolymer was characterized by GPC, H-1 NMR, and DSC. In the case of styrene and MA, the formation o f triblock copolymers was significantly slower.