Hyperbranched–linear–hyperbranched ABA‐type block copolymers based on poly(ethylene oxide) and polyglycerol

Abstract

BACKGROUND: Until recently, hyperbranched polymers were thought to be ill‐defined materials that were not useful as building blocks for well‐defined complex polymer architectures. It is a current challenge to develop strategies that offer rapid access to well‐defined hyperbranched block copolymers. RESULTS: A convenient three‐step protocol for the synthesis of double‐hydrophilic hyperbranched–linear–hyperbranched ABA‐type triblock copolymers based on poly(ethylene oxide) (PEO) and hyperbranched polyglycerol (hbPG) is presented. The Bola‐type polymers exhibiting an aliphatic polyether structure were prepared from a linear (lin) linPG‐b‐PEO‐b‐linPG precursor triblock. The materials exhibit low polydispersities (Mw/Mn) in the range 1.19–1.45. The molecular weights of the block copolymers range from 6300 to 26 200 g mol−1, varying in the length of both the linear PEO chain as well as the hbPG segments. Detailed characterization of the thermal properties using differential scanning calorimetry demonstrates nanophase segregation of the blocks. CONCLUSION: The first example of well‐defined ABA hyperbranched–linear–hyperbranched triblock copolymers with PEO middle block and hbPG A‐blocks is presented. The biocompatible nature of the aliphatic polyether blocks renders these materials interesting for biomedical purposes. These new materials are also intriguing with respect to their supramolecular order and biomineralization properties. Copyright © 2009 Society of Chemical Industry

α,ωn‐Heterotelechelic Hyperbranched Polyethers Solubilize Carbon Nanotubes

“…13 C NMR spectra are referenced internally to solvent signals and were recorded at 100.15 MHz. FT-IR spectra were recorded on a Nicolet SDXC FT-IR spectrometer equipped with an ATR unit.…”

“…Ethoxyethyl glycidyl ether (EEGE) or isopropylidene(glyceryl glycidyl ether) (IGG) was prepared as described in literature, [13,17] dried over CaH 2 , and freshly distilled before used. The procedure for introduction of sulfate groups into hyperbranched poly(glycerol) can be found elsewhere and was adopted.…”

“…[12] Polydispersity can be further reduced (<1.3) by using a two-step protocol for the synthesis of double-hydrophilic linear-hyperbranched (linhb) block copolymers based on PEG and hbPG that are merely built up from biocompatible segments avoiding any other linkages than aliphatic ethers. [13] In related works, amphiphilic derivatives with hbPG segments have also been developed. [14] In order to obtain biocompatible conjugates of MWCNTs, PEG as one of the most important biocompatible, watersoluble polymers has been employed.…”

Polyethylene-block-hyperbranched polyglycerol diblock copolymers: synthesis, thermal property and compatibilization

“…Furthermore, the DP, M w /M n and DB of hyperbranched moieties were efficiently controlled by slow monomer addition (SMA) method, almost perfect hyperbranched structures were obtained [10][11][12][13][14]. Although a number of LHBCs containing hbPG segments have been reported, it is worth emphasizing that the linear polymer blocks are poly(ethylene oxide) (PEO) [15][16][17][18], poly(propylene oxide) (PPO) [19], polystyrene (PS) [20,21], polyethylene glycol (PEG) [22] and so on. To the best of our knowledge, these linear blocks are either polar or noncrystalline, as a result, the corresponding copolymers are doublehydrophilic or double-noncrystalline.…”

Hyperbranched aliphatic polyether polyols

“…These materials are available over a broad range of molecular weights and with up to 300 end groups. 138 Moreover, some other triblock copolymers with hyperbranched PEHO and linear PEG blocks, 136 or linear poly(tetrahydrofuran) (PTHF) and hbPG were described. 139 In summary, the use of aliphatic polyether polyols, especially hyperbranched polyglycerol as building blocks for the synthesis of LHBCs with controlled molecular weights and tailored molecular architecture, is advantageous.…”