Influence of Reaction Conditions on Degree of Branching in Hyperbranched Aliphatic Polyethers from 3-Ethyl-3-(hydroxymethyl)oxetane

Magnusson, Heléne; Malmström, Eva; Hult, Anders

doi:10.1021/ma010495s

Cited by 73 publications

(55 citation statements)

References 25 publications

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“…Both types of hydroxyl groups may have different reactivity; thus, the relative contribution of both mechanisms may change during the polymerization. 47 Magnusson and Malmstrom 49 observed that the content of branched units increases with increasing monomer conversion. An increasing contribution of the AM mechanism in the course of the polymerization can be deduced.…”

Section: Anionic Ring-opening Multibranching Polymerizationmentioning

confidence: 99%

“…The polydispersity was generally slightly lower when a core molecule was used compared with the one-step homopolymerization. 49 Detailed mechanistic investigations led to the conclusion that the polymerization proceeds with participation of both the ACE and the AM mechanism. 81 An interesting finding is that M n does not increase with monomer conversion and that there seems to be an upper limit of achievable molecular weights, regardless of the reaction conditions.…”

Section: Polyglycerolmentioning

confidence: 99%

“…Only a small change of the DB value can be observed when the reaction temperature exceeds 20 C, which might explain why this effect was not observed by other groups. 49 The limitation of the molecular weight could partly be overcome by copolymerization of EHO with the dihydroxy-substituted dioxetane comonomer (diHO-diOX), yielding polymers with M n close to 7000 g mol À1 . 85 However, in the copolymerization, EHO is consumed first, and consequently, the process is not a true copolymerization, but can be rather described as coupling of PEHO macromolecules formed at the first stage by the difunctional monomer as a coupling agent.…”

Section: Highlightmentioning

confidence: 99%

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Hyperbranched aliphatic polyether polyols

Schömer

Schüll

Frey

2012

J. Polym. Sci. A Polym. Chem.

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Hyperbranched polymers, dendritic macromolecules with branch-on-branch structures, have become an important polymer class since the early 1990s. They combine several advantages of the perfectly branched dendrimers with easy accessibility, typically in a one-step synthesis. Hyperbranched polyethers are a particularly interesting class of chemically stable and often biocompatible materials. Multifunctional hyperbranched polyethers with controllable molar mass and comparably low polydispersities can been prepared using hydroxyl-functional epoxides or oxetanes for polymerization via anionic and cationic polymerization mechanisms. Here, we review the progress in the preparation, characterization, and application of these uniquely versatile aliphatic polyether polyols. Their unusual mechanical, thermal, and solution properties render them useful for a variety of applications, for example, as building blocks for various complex macromolecular architectures or in biomedical applications.

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Section: Anionic Ring-opening Multibranching Polymerizationmentioning

confidence: 99%

Section: Polyglycerolmentioning

confidence: 99%

Section: Highlightmentioning

confidence: 99%

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Hyperbranched aliphatic polyether polyols

Schömer

Schüll

Frey

2012

J. Polym. Sci. A Polym. Chem.

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“…1 Vandenberg et al 2 reported the synthesis of the polyethers by the cationic ring-opening polymerization of 3-ethyl-3-hydroxymethyloxetane (EHO) in the presence of aluminum complexes as cationic initiators. Recently, Hult et al 3 reported the synthesis of hyperbranched polyethers by the cationic ring-opening polymerization of EHO using various cationic initiators. Penczek et al 4 reported that the cationic ring-opening polymerizations of 3,3-bis(hydroxymethyl)oxetane (BHO), and the copolymerization of BHO with EHO were performed to give medium molecular-weight polymers in good yields.…”

mentioning

confidence: 99%

Synthesis of Hyperbranched Polymers by the Anionic Ring-Opening Polymerization of 3,3-Bis(hydroxymethyl)oxetane

Morita

Kudo

Nishikubo

2004

Polym J

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ABSTRACT:The anionic ring-opening polymerization of 3,3-bis(hydroxymethyl)oxetane (BHO) was carried out using t-BuOK as an initiator in the presence of 18-crown-6-ether (18-C-6) in NMP at 180 C, affording the corresponding hyperbranched polyethers, poly(BHO)s containing an oxetanyl group and many hydroxyl groups at the ends in 83-98% yields. Since the resulting poly(BHO)s were insoluble in common organic solvents, the poly(BHO)s were treated with acetic anhydride to obtain poly(BHO-Ac)s containing acetyl groups at the ends. The M n s and degree of branching (DB) of poly(BHO-Ac)s were in the range of 2600-4400 estimated by SEC and 0.09-0.55 calculated by 13 C NMR spectroscopy, respectively. The cationic copolymerization of poly(BHO-Ac) and 3-ethyl-3-phenoxymethyloxetane (EPO) was examined using BF 3 reported the synthesis of hyperbranched polyethers by the cationic ring-opening polymerization of EHO using various cationic initiators. Penczek et al. 4 reported that the cationic ring-opening polymerizations of 3,3-bis(hydroxymethyl)oxetane (BHO), and the copolymerization of BHO with EHO were performed to give medium molecular-weight polymers in good yields.Meanwhile, we have developed many new reactions of oxetanes with various protonic reagents such as phenols, 5 thiophenols, 6 carboxylic acids, 7 and thioesters 8 in the presence of quaternary onium salts or crown ether complexes as catalysts. These new reactions have been applied to the synthesis of polymers such as polyethers, 5 polyesters, 7,9 polyphosphonates, 10 and poly(silyl ether)s. 11 Furthermore, we have found anionic alternating ring-opening copolymerization of oxetanes with carboxylic anhydrides in the presence of the quaternary onium salts as initiators.12 Inoue and Endo et al. preformed the living anionic polymerization of oxetanes using metal complexes as catalysts. [13][14][15][16][17] More recently, we reported a new anionic ringopening polymerization of EHO and 3-methyl-3-hydroxymethyloxetane (MHO) containing hydroxyl groups using potassium tert-butoxide (t-BuOK) and 18-crown-6-ether (18-C-6), affording the hyperbranched polyether containing an oxetanyl group and many hydroxyl groups at the end (Scheme 1).18,19 Furthermore, we achieved the synthesis of a pseudo dendritic polymer with many pendant hydroxyl groups by the cationic ring-opening polymerization of the poly(EHO) derivative.19 These synthesized polymers poly(EHO), poly(MHO), and pseudo dendritic polymers are expected as useful functional materials, because they have many hydroxyl groups at the ends.In a series of the study for the synthesis of hyperbranched polyether by the anionic ring-opening polymerization of the oxetane with hydroxyl groups in this article, we examined the reaction of BHO containing two hydroxyl groups in the presence of t-BuOK in several conditions in detail. Furthermore, we also examined the reaction of the resulting polymers for the synthesis of new branched polymers containing pendant many hydroxyl groups. EXPERIMENTAL MaterialsThe solvents, chloroform (CHCl 3 ...

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“…2,3 Hyperbranched polymers by cationic ring-opening polymerization of EHO using sulfonium salts as cationic initiators have been reported. [4][5][6][7] Inoue et al performed living anionic polymerization of oxetanes using aluminum porphyrin/Lewis acid as catalyst. 8 The authors have developed useful reactions of oxetanes for synthetic organic chemistry and polymer synthesis.…”

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confidence: 99%

Synthesis of a Hetero Telechelic Hyperbranched Polyether. Anionic Ring-Opening Polymerization of 3-Ethyl-3-(hydroxymethyl)oxetane Using Potassium tert-Butoxide as an Initiator

Kudo

Morita

Nishikubo

2003

Polym J

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KEY WORDSHetero Telechelic Hyperbranched / Anionic Polymerization / Polyethers / 3-Ethyl-3-(hydroxymethyl)oxetane / Oxetanes with 4-membered ring are polymerized exclusively with cationic initiators, due to high basicity. 1 Vandenberg et al. reported that cationic ring-opening polymerization of 3-ethyl-3-(hydroxymethyl)-oxetane (EHO) in the presence of aluminum complexes as cationic initiators produced linear polymers with high crystallinity and no glass transition temperature. 2, 3 Hyperbranched polymers by cationic ring-opening polymerization of EHO using sulfonium salts as cationic initiators have been reported. [4][5][6][7] Inoue et al. performed living anionic polymerization of oxetanes using aluminum porphyrin/Lewis acid as catalyst. 8 The authors have developed useful reactions of oxetanes for synthetic organic chemistry and polymer synthesis. 9 No research has been done on the anionic polymerization of oxetanes using common anionic initiators such as butyllithium (BuLi), sodium methoxide (MeONa), potassium tert-butoxide (t-BuOK) and etc.Herein, we describe successful results of the anionic ring-opening polymerization of oxetane, 3-ethyl-(3-hydroxymethyl)oxetane (EHO), affording hetero telechelic hyperbranched polyethers, poly(EHO)s containing an oxetanyl and many hydroxyl groups at the ends. EXPERIMENTAL Materials18-Crown-6-ether (18-C-6) was recrystallized twice from acetnitrile. t-BuOK was purified by the sublimation. 3-Ethyl-3-(hydroxymethyl)-oxetane (EHO) was donated from Toagosei Co., Ltd. and distilled over MgSO 4 before use. InstrumentationInfrared (IR) absorption spectra were measured on a Jasco model IR-420 spectrometer. 1 H and 13 C NMR spectra were recorded on a JEOL model JNM α-500 (500 MHz for 1 H NMR and 125 MHz for 13 C NMR) in DMSO-d 6 with Me 4 Si (TMS) as internal standard. The degree of branching was calculated from relative intensity of the -CH 2 CH 3 in proton decoupled, quantitative 13 C NMR spectra. Number-average molecular weight (M n ) and weight-average molecular weight (M w ) of the polymers were estimated by gel permeation chromatography (GPC; TOSOH model HLC-8020) on TSK gel Multipore Hxl-M columns calibrated by narrow molecular weight polystyrene standards and with solution of LiBr and phosphoric acid (20 mM) in dimethylformamide (DMF) as eluent without correction with a refractive index detector. T g s were measured on a Seiko Electronic Instrument (SSC5200/DSC120) differential scanning calorimeter (DSC) at a heating rate of 10 • C min −1 under a nitrogen atmosphere. Thermal analysis was performed on a Seiko Electronic Instrument (TG/DTA 120) at a heating rate of 10 • C min −1 for thermogravimetric analysis (TGA) under nitrogen. Matrixassisted laser desorption ionization time-of flight mass (MALDI-TOF-MS) experiments were performed SHI-MAZU/KRATOS MALDI-TOF-MS using dihydroxy benzoic acid as matrix and chloroform as solvent. Synthesis of Hyperbranched Polyethers by the Polymerization of 3-Ethyl-(3-hydroxymethyl)oxetane (EHO).A typical procedure for the polymerization of E...

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Influence of Reaction Conditions on Degree of Branching in Hyperbranched Aliphatic Polyethers from 3-Ethyl-3-(hydroxymethyl)oxetane

Cited by 73 publications

References 25 publications

Hyperbranched aliphatic polyether polyols

Hyperbranched aliphatic polyether polyols

Synthesis of Hyperbranched Polymers by the Anionic Ring-Opening Polymerization of 3,3-Bis(hydroxymethyl)oxetane

Synthesis of a Hetero Telechelic Hyperbranched Polyether. Anionic Ring-Opening Polymerization of 3-Ethyl-3-(hydroxymethyl)oxetane Using Potassium tert-Butoxide as an Initiator

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