Synthesis of tri-arm star di-block co-polymer containing poly(tetrahydrofuran-b-methyl methacrylate) arms via combination of cationic ring-opening polymerization and photosensitized free radical polymerization routes

Trimesic acid trichloride was used as a core to prepare a tri-arm star di-block copolymer, namely poly(tetrahydrofuran-b-methyl methacrylate) (PTHF₃-b-PMMA₃), via combination of cationic ring-opening polymerization (CROP) and photo-induced radical polymerization routes. First, a trimesic acid trichloride-AgSbF₆ or -AgCF₃SO₃ initiation system was utilized for the CROP of THF. The tri-arm star PTHF thus obtained was in situ terminated by 2-methyl pyridine N-oxide. Second, a sensitized irradiation of PTHF with a 2-methyl pyridinium N -oxide photoactive endgroup in the presence of anthracene initiated the radical polymerization of MMA in order to give resulting star di-block co-polymer. The obtained polymers were characterized with gel-permeation chromatography (GPC) and ¹H-NMR.