Block and star block copolymers by mechanism transformation. VI. Synthesis and characterization of A4B4 miktoarm star copolymers consisting of polystyrene and polytetrahydrofuran prepared by cationic ring‐opening polymerization and atom transfer radical polymerization

Abstract

The synthesis of A 4 B 4 miktoarm star copolymers, where A is polytetrahydrofuran (PTHF) and B is polystyrene (PSt), was accomplished with orthogonal initiators and consecutive cationic ring-opening polymerization (CROP) and atom transfer radical polymerization (ATRP). The compound formed in situ from the reaction of 3-{2,2-bis[2-bromo-2-(chlorocarbonyl) ethoxy] methyl-3-(2-chlorocarbonyl) ethoxy} propoxyl-2-bromopropanoyl chloride [C(CH 2 OCH 2 CHBrCOCl) 4 ] with silver perchlorate was used to initiate the CROP of tetrahydrofuran. The obtained polymer contained four secondary bromine groups at the ␣ position to the original initiator sites and was used to initiate the ATRP of styrene with a CuBr/2,2Ј-bipyridine catalyst to form a C(PTHF) 4 (PSt) 4 miktoarm star copolymer. The miktoarm copolymer was characterized by gel permeation chromatography and 1 H NMR. The macroinitiator C(PTHF) 4 Br 4 was hydrolyzed to afford PTHF arms.

Atom transfer radical copolymerization of N‐phenylmaleimide and styrene initiated with dendritic polyarylether 2‐bromoisobutyrate

“…Recently, significant progress has been made in the field of living free‐radical polymerization such as nitroxide‐mediated stable free‐radical polymerization,1–4 atom transfer radical polymerization (ATRP),5–12 reverse ATRP,13–16 and reversible addition–fragmentation chain transfer 17–20. Among them, ATRP has been extensively investigated and successfully applied to the synthesis of well‐defined macromolecular architectures such as comb,21–23 star,24–26 hyperbranched, and dendritic macromolecules 27–30…”

Cationic polymerization of styrene on the surface of graphite expanded

“…In our previous research19–21 on cationic ring‐opening polymerization, CO + ClO was used as the initiator and was also an initiator for cationic polymerization of St. Therefore, the cationic solution polymerization of St in CH 2 Cl 2 was carried out with EG‐COCl in conjunction with AgClO 4 .…”

Poly(styrene‐b‐tetrahydrofuran)/clay nanocomposites by mechanistic transformation

“…Mechanistic transformation provides a facile route to synthesis of block copolymers that cannot be made by a single polymerization mode 36–40. In this concept, a polymer, obtained by a particular polymerization mechanism, is functionalized either by initiation or termination steps 41–44. The polymer is isolated and purified, and finally, the functional groups are converted into another kind of species capable of initiating the polymerization of the second monomer 45, 46.…”