Synthesis of well‐defined second‐generation dendritic polymers of isoprene (I) and styrene (S): (S2I)3, (SI′I)3, (I″I′I)3, and (I′2I)4

Chalari, Ioanna; Hadjichristidis, Nikos

doi:10.1002/pola.10233

Cited by 92 publications

(89 citation statements)

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“…More recently numerous strategies have been devised to synthesize more complex branched architectures with various resulting structures and differing degrees of control, including syntheses of dendrigraft, dendritically branched and arborescent [8][9][10][11][12][13] polymers, much of this work has recently been reviewed by Gauthier and Teertstra 14 . A number of examples of well defined dendritically branched polymers, essentially analogues of classical dendrimers with an additional polymer chain between branch points have also been reported, notably by Hadjichristidis 15 , Gnanou 8,16 , Hedrick 17 and Hirao 18,19 .…”

Section: Introductionmentioning

confidence: 99%

DendriMacs. Well-Defined Dendritically Branched Polymers Synthesized by an Iterative Convergent Strategy Involving the Coupling Reaction of AB₂ Macromonomers

2006

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. (2006) 'DendriMacs : well-dened dendritically branched polymers synthesized by an iterative convergent strategy involving the coupling reaction of AB2 macromonomers. ', Macromolecules., 39 (6). pp. 2144-2152. Further information on publisher's website:http://dx.doi.org/10.1021/ma052627dPublisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Macromolecules, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://pubs.acs.org/doi/abs/10.1021/ma052627d. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACT. We describe here the first example of an iterative convergent strategy for the synthesis of dendritically branched polymers involving condensation coupling reactions of AB 2 macromonomers.The macromonomers were synthesized by living anionic polymerization, initiated with 3-tertbutyldimethylsiloxy-1-propyllithium and end capped with 1,1-bis(4-tert-butyldimethylsiloxyphenyl)ethylene. Following a deprotection reaction, the macromonomer, functionalized with two phenol groups and one primary alcohol group, can be built up into a dendritic structure by a series of Williamson coupling reactions and subsequent end group modification reactions. Since the Dendritic structures are built up from Macromonomers we have coined the term 'DendriMac' to describe these branched 2 polymers. In this paper we will discuss the synthesis of the macromonomer, the iterative reaction sequence and merits of a convergent strategy. Some preliminary characterization data will also be reported.

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Section: Introductionmentioning

confidence: 99%

DendriMacs. Well-Defined Dendritically Branched Polymers Synthesized by an Iterative Convergent Strategy Involving the Coupling Reaction of AB₂ Macromonomers

2006

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“…The optimal long chain branched polymer architecture for structure property correlation studies will have multiple generations of hierarchical branching in which not only is the molecular weight of each linear segment well defined but the position of each branch is also well controlled. These structures might be described as long chain branched analogues of dendrimers and the synthesis of such structures have been reported, notably by Hadjichristidis [22], Gnanou [9,23], Hedrick [24], Hirao [25,26], ourselves [27] and recently reviewed [28]. However in each case without exception the synthesis is time consuming involves multiple reaction steps and yields modest amounts of material.…”

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confidence: 99%

HyperMacs – long chain hyperbranched polymers: A dramatically improved synthesis and qualitative rheological analysis

Clarke

Luca

Dodds

et al. 2008

European Polymer Journal

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. (2008) 'HyperMacs long chain hyperbranched polymers : a dramatically improved synthesis and qualitative rheological analysis.', European polymer journal., 44 (3). pp. 665-676. Further information on publisher's website:http://dx.doi.org/10. 1016/j.eurpolymj.2007.12.022 Publisher's copyright statement: NOTICE: this is the author's version of a work that was accepted for publication in European Polymer Journal. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be re ected in this document. Changes may have been made to this work since it was submitted for publication. A de nitive version was subsequently published in European Polymer Journal, 44, 3, March 2008, 10.1016/j.eurpolymj.2007 Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Abstract.We have previously reported a novel (albeit modestly successful) strategy for the synthesis of polystyrene HyperMacs -long chain branched analogues of hyperbranched polymers.The building blocks for HyperMacs, AB 2 macromonomers are synthesized by living anionic polymerization and as such are well-defined in terms of molecular weight and polydispersity but the nature of the coupling reaction used to generate the highly branched HyperMacs results in branched polymers with a distribution of molecular weights and architectures. In our previously reported studies the extent of the coupling reaction was significantly hampered by side reactions, however, we report here dramatic improvements to the coupling chemistry which overcome the previously experienced limitations resulting in a four fold increase in the extent of the coupling reactions.Furthermore we report the effect of the addition of varying amounts of a B 3 core molecule to the coupling reaction and the resultant 'control' of the final molecular weight of the HyperMac. Melt rheology showed polystyrene HyperMacs to be thermorheologically simple, obeying WilliamLandel-Ferry (WLF) behaviour. HyperMacs showed little evidence for relaxation by reptation and when the molecular weight of the macromonomer was ≤ M e for polystyrene, HyperMacs resemble unentangled polymers below the gel point, despite being well above the entanglement molecular weight for linear polystyrene. Increasing the molecular weight of the macromonomer to substantially above Me seems to introduce some entangled nature to the HyperMac as evidenced by the emergence of a near horizontal plateau in G'' -the loss modulus.

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“…This strategy has already been successfully used in the stepwise convergent synthesis of dendritic polymers using living anionic polymerization. [ 26 ] However, to our best knowledge, this approach has never been used with living ROMP. The functional or nonfunctional termination of ROMP is typically achieved by using large excesses of ethyl vinyl ether, [ 27 ] vinyl lactones, [ 13 ] or other terminating agents [7][8][9][10] in order to ensure high reaction rates.…”

Section: Resultsmentioning

confidence: 99%

Branched Polymers via ROMP of Termimers

Hanik

Kilbinger

2016

Macromol. Rapid Commun.

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the desired chemical moiety. In the living ring-opening metathesis polymerization employing Grubbs' ruthenium carbene complexes the reactive site is the propagating catalyst species, i.e., the ruthenium alkylidene complex. However, when utilizing ruthenium carbene complexes, their high tolerance towards oxygen, water and many polar functional groups impede the desired transformation into a functional end group since the number of potential reactants other than olefi ns is limited. Thus, what is generally considered one of the great advantages of ruthenium catalyzed olefi n metathesis is a slight disadvantage in this particular case.Nonetheless, several methods have been recently reported by our group that allow the mono end-functionalization of ROMP polymers with specifi c functional groups such as alcohols, [ 10,11 ] aldehydes and carboxylic acids, [ 12 ] thiols, [ 13 ] and amines. [ 14 ] By end-functionalizing living ROMP polymers using a cyclohexene derivative, a catalytic living ring opening metathesis process could even be achieved. [ 15 ] Synthesizing these end-functional polymers becomes especially useful when using them as macroinitiators for multiblock copolymer syntheses, building blocks for model networks or as macromonomers or prepolymers to reach very high molecular weights in subsequent polymerizations.Here, we describe the synthesis of a functionalizable cis -vinyl ether end-capping reagent that allows the Today's olefi n metathesis catalysts show high reactivity, selectivity, and functional group tolerance and allow the design of new syntheses of precisely functionalized polymers. Here the synthesis of a new end-capping reagent is investigated allowing the introduction of a highly reactive activated ester end-group at the polymer chain end as well as its prefunctionalization to directly introduce functional moieties. The versatility of this new end-capping reagent is demonstrated by utilizing it to synthesize a so-called termimer (a monomer with termination capabilities). Copolymerization of a norbornene derivative with the termimer leads to hyperbranched ring-opening metathesis polymerization polymers as proven by gel permeation chromatography and MALDI-ToF-(matrix-assisted laser desorption/ ionization time of fl ight) mass spectrometry.

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Synthesis of well‐defined second‐generation dendritic polymers of isoprene (I) and styrene (S): (S₂I)₃, (SI′I)₃, (I″I′I)₃, and (I′₂I)₄

Cited by 92 publications

References 24 publications

DendriMacs. Well-Defined Dendritically Branched Polymers Synthesized by an Iterative Convergent Strategy Involving the Coupling Reaction of AB₂ Macromonomers

DendriMacs. Well-Defined Dendritically Branched Polymers Synthesized by an Iterative Convergent Strategy Involving the Coupling Reaction of AB₂ Macromonomers

HyperMacs – long chain hyperbranched polymers: A dramatically improved synthesis and qualitative rheological analysis

Branched Polymers via ROMP of Termimers

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Synthesis of well‐defined second‐generation dendritic polymers of isoprene (I) and styrene (S): (S2I)3, (SI′I)3, (I″I′I)3, and (I′2I)4

Cited by 92 publications

References 24 publications

DendriMacs. Well-Defined Dendritically Branched Polymers Synthesized by an Iterative Convergent Strategy Involving the Coupling Reaction of AB2 Macromonomers

DendriMacs. Well-Defined Dendritically Branched Polymers Synthesized by an Iterative Convergent Strategy Involving the Coupling Reaction of AB2 Macromonomers

HyperMacs – long chain hyperbranched polymers: A dramatically improved synthesis and qualitative rheological analysis

Branched Polymers via ROMP of Termimers

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Synthesis of well‐defined second‐generation dendritic polymers of isoprene (I) and styrene (S): (S₂I)₃, (SI′I)₃, (I″I′I)₃, and (I′₂I)₄

DendriMacs. Well-Defined Dendritically Branched Polymers Synthesized by an Iterative Convergent Strategy Involving the Coupling Reaction of AB₂ Macromonomers

DendriMacs. Well-Defined Dendritically Branched Polymers Synthesized by an Iterative Convergent Strategy Involving the Coupling Reaction of AB₂ Macromonomers