Synthesis of a novel graft copolymer with hyperbranched poly(glycerol) as core and “Y”‐shaped polystyrene‐b‐poly(ethylene oxide)₂ as side chains

Abstract

The graft copolymers composed of “Y”‐shaped polystyrene‐b‐poly(ethylene oxide)2 (PS‐b‐PEO2) as side chains and hyperbranched poly(glycerol) (HPG) as core were synthesized by a combination of “click” chemistry and atom transfer radical polymerization (ATRP) via “graft from” and “graft onto” strategies. Firstly, macroinitiators HPG‐Br were obtained by esterification of hydroxyl groups on HPG with bromoisobutyryl bromide, and then by “graft from” strategy, graft copolymers HPG‐g‐(PS‐Br) were synthesized by ATRP of St and further HPG‐g‐(PS‐N3) were prepared by azidation with NaN3. Then, the precursors (Bz‐PEO)2‐alkyne with a single alkyne group at the junction point and an inert benzyl group at each end was synthesized by sequentially ring‐opening polymerization (ROP) of EO using 3‐[(1‐ethoxyethyl)‐ethoxyethyl]‐1,2‐propanediol (EEPD) and diphenylmethylpotassium (DPMK) as coinitiator, termination of living polymeric species by benzyl bromide, recovery of protected hydroxyl groups by HCl and modification by propargyl bromide. Finally, the “click” chemistry was conducted between HPG‐g‐(PS‐N3) and (Bz‐PEO)2‐alkyne in the presence of N,N,N′,N″,N”‐pentamethyl diethylenetriamine (PMDETA)/CuBr system by “graft onto” strategy, and the graft copolymers were characterized by SEC, 1H NMR and FTIR in details. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Hyperbranched aliphatic polyether polyols

“…Moreover, block copolymer arms were attached using the same ATRP strategy, for example, to polymerize polystyrene‐ block ‐poly( tert butyl acrylate) and polystyrene‐ block ‐poly(acrylic acid) arms171 or polystyrene‐ block ‐poly(ethylene oxide) arms. In the latter case, poly(ethylene oxide) blocks were attached by a radical coupling reaction after the ATRP of styrene from the core172 or by azide‐alkyne click chemistry 173. Reversible addition–fragmentation chain transfer polymerization (RAFT)174, 175 is another versatile controlled radical polymerization technique that can be used for the synthesis of MSPs after attachment of suitable functional groups to the hb PG core.…”

“…In the latter case, poly(ethylene oxide) blocks were attached by a radical coupling reaction after the ATRP of styrene from the core 172 or by azidealkyne click chemistry. 173 Reversible addition-fragmentation chain transfer polymerization (RAFT) 174,175 is another versatile controlled radical polymerization technique that can be used for the synthesis of MSPs after attachment of suitable functional groups to the hbPG core. For example, hbPG with poly(N-isopropylacrylamide) arms, that exhibits thermoresponsive properties, have been described.…”

Controlling the formation of long‐subchain hyperbranched polystyrene from seesaw‐type AB2 macromonomers: Solvent polarity and solubility

“…Actually, there are other synthetic routes which may occasionally lead to the topology of lsc ‐hp, including to the introduction of small AB monomers to AB 2 system,29 self‐condensed vinyl polymerization,30 and ring‐opening multibranching polymerization31 or so‐called self‐condensation ring‐opening polymerization 32. The linear subchains between branching points are produced due to the random copolymerization behavior among different monomers and inimers.…”

Convenient synthesis of thermo‐responsive PtBA‐g‐PPEGMEMA well‐defined amphiphilic graft copolymer without polymeric functional group transformation

“…The development of various controlled/living radical polymerization such as atom transfer radical polymerization (ATRP),18–20 single‐electron‐transfer living radical polymerization (SET‐LRP),21–25 and reversible addition fragmentation chain transfer (RAFT) polymerization26, 27 popularizes the grafting‐from approach, which utilizes the pendant initiation sites on the backbone to initiate the polymerization of another monomer to form the side chains 28. The synthesis of graft copolymers usually needs further postpolymerization modification of the prefabricated backbones to afford pendant initiation sites according to previous literatures 17, 29–37. For example, chemists often convert the hydroxyl side groups on the backbone into the pendant initiation groups by esterification 37, 38.…”

“…The synthesis of graft copolymers usually needs further postpolymerization modification of the prefabricated backbones to afford pendant initiation sites according to previous literatures 17, 29–37. For example, chemists often convert the hydroxyl side groups on the backbone into the pendant initiation groups by esterification 37, 38. Thus, developing a more convenient way to synthesize well‐defined graft copolymers without polymeric functional group transformation is highly desirable.…”