Linear-Hyperbranched Graft-Copolymers via Grafting-to Strategy Based on Hyperbranched Dendron Analogues and Reactive Ester Polymers

Abstract

The synthesis of hyperbranched polyglycerol dendron analogues with precisely one focal amino functionality (H 2 N-hbPG) and their use for the synthesis of linear-hyperbranched graftcopolymers in a grafting-to approach is reported. By use of N,Ndibenzyl tris(hydroxylmethyl) aminomethane as a novel initiator for the ring-opening multibranching polymerization of glycidol, dendron analogues with one focal amino functionality of molecular weights ranging from 500 to 15000 g mol −1 and narrow to moderate polydispersities (M w /M n = 1.2−1.9) were synthesized, as confirmed by NMR and SEC. After removal of the benzyl protective groups, the accessibility and selective transformation of the focal amino group was demonstrated by NMR and MALDI−ToF MS. H 2 N-hbPG was then selectively grafted to a linear reactive ester polymer backbone, poly(pentafluorophenol methacrylate) (PPFPMA), to obtain linear polymers with highly branched side chains of high molecular weights (M n > 126 kg mol −1 ) and low polydispersities (M w /M n = 1.1−1.3), as shown by SEC. Successful attachment of the hyperbranched polyether structure to the linear backbone was confirmed by 19 F NMR and fluorescence spectroscopy. The modular approach introduced bears some analogy to the convergent dendrimer synthesis and describes the first linearhyperbranched graft-copolymers prepared in a graf ting-to approach, resulting in hyperbranched brush-type polymers with the highest molecular weight reported to date.

Activated Ester Containing Polymers: Opportunities and Challenges for the Design of Functional Macromolecules

“…91,92 This makes the PPM approach effective for structure−property relationship studies of those biologically active polymers under physiological conditions. Frey et al 93 reported the synthesis of linear-hyperbranched graft-copolymers of polyHPMA via "grafting-to" approach by sequential modification of polyPFPMA backbone with a dendritic amine followed by 2-hydroxypropylamine. In a slightly different strategy, they synthesized polyHPMA with pendent β-cyclodextrin via triple PPM of polyPFPMA obtained by RAFT.…”

Directing the Self‐Assembly of Semiconducting Copolymers: The Consequences of Grafting Linear or Hyperbranched Polyether Side Chains

“…Subsequently, the PEG or hb PG side chains were introduced at the reactive PFPA block by a grafting‐to approach using their monoamino derivatives resulting in poly( para ‐(2,5‐bis pentyloxy)phenylene vinylene)‐ block ‐poly(poly(ethylene glycol) acryl amide) (BPO‐PPV‐ b ‐P(PEG)AA) and poly( para ‐(2,5‐bis pentyloxy)phenylene vinylene)‐ block ‐poly((hyperbranched polyglycerol) acryl amide) (BPO‐PPV‐ b ‐P( hb PG)AA). PFPA is an excellent component for this strategy, since the reactive esters react selectively and quantitatively with amines without cross‐linking, despite the presence of multiple alcohols in hb PG . Studies of the polymers by transmission electron microscopy (TEM) in various solvents revealed different self‐assembled structures, depending on the topology and the molecular weight of the polyether side chains.…”

“…For the synthesis of the graft copolymers with linear and hyperbranched side chains, P1 was reacted both with α‐methoxy‐ω‐amino polyethylene glycol (PEG‐NH 2 ) and hb PG dendron analogues with a single focal amino functionality ( hb PG‐NH 2 ), respectively in polymer modification reactions (Scheme and Table ). Commercially obtained PEG‐NH 2 with molecular weights () of 700 and 5000 g mol −1 was used to synthesize two graft copolymers ( P3 with PEG 750 and P4 with PEG 5000 ).…”

Hyperbranched aliphatic polyether polyols

“…145 In this work, hyperbranched polyglycerol dendron analogs with a single focal amino functionality (H 2 N-hbPG) were attached to a reactive ester polymer (poly(pentafluorophenol methacrylate), PPFPMA) (Fig. 28).…”