Block and Star Block Copolymers by Mechanism Transformation. 7. Synthesis of Polytetrahydrofuran/Poly(1,3-dioxepane)/Polystyrene ABC Miktoarm Star Copolymers by Combination of CROP and ATRP

Polytetrahydrofuran (PTHF)/poly(1,3-dioxepane) (PDOP)/polystyrene (PSt) ABC miktoarm star copolymers were synthesized by combination of cationic ring-opening polymerization (CROP) and atom transfer radical polymerization. Two different functional groups, carboxylic acid and CHBr, were capped at one end of PTHF through the reaction of PTHF−OH with 2-bromosuccinic anhydride (BSA). After PTHF−OOCCHBrCH 2 COOH reacted with thionyl chloride, block copolymer PTHF- b -PDOP was synthesized by CROP of DOP at −30 to −35 °C with PTHF−OOCCHBrCH 2 COCl and AgClO 4 as catalyst. Finally, (PTHF) (PDOP)−Br was used to initiate the polymerization of St in the presence of CuBr and bipyridine at 110 °C, and ABC miktoarm star polymer, s-[(PTHF) (PDOP) (PSt)] was successfully prepared. The copolymers obtained were characterized by 1 H NMR and gel permeation chromatography measurements.