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Search for "block copolymers" in Full Text gives 35 result(s) in Beilstein Journal of Organic Chemistry.

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  • of thermo-responsive micelles of end-group functionalized respectively block copolymers in aqueous solution have been investigated in previous studies [35][48][49]. Studies on hydrophobically PNIPAM have also demonstrated the formation of core-shell structures exhibiting a corona of PNIPAM chains [25
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Published 19 Mar 2014

Organotellurium-mediated living radical polymerization under photoirradiation by a low-intensity light-emitting diode

  • Yasuyuki Nakamura and
  • Shigeru Yamago

Beilstein J. Org. Chem. 2013, 9, 1607–1612, doi:10.3762/bjoc.9.183

Graphical Abstract
  • ], and facile living-end transformation for the synthesis of block copolymers [30][31][32][33][34] and end-functional polymers [35][36]. Furthermore, we recently reported that photochemical stimuli were efficient in the activation of organotellurium dormant species, and that TERP proceeded under mild
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Published 07 Aug 2013

The synthesis of well-defined poly(vinylbenzyl chloride)-grafted nanoparticles via RAFT polymerization

  • John Moraes,
  • Kohji Ohno,
  • Guillaume Gody,
  • Thomas Maschmeyer and
  • Sébastien Perrier

Beilstein J. Org. Chem. 2013, 9, 1226–1234, doi:10.3762/bjoc.9.139

Graphical Abstract
  • with narrow dispersity (<1.5) and complex architectures (i.e., block copolymers) [1]. By exploiting a dormant state of the propagating radical of a growing chain, it is possible to limit the proportion of irreversibly terminated chains in a radical polymerization, and thus to control the final
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Published 25 Jun 2013

Restructuring polymers via nanoconfinement and subsequent release

  • Alan E. Tonelli

Beilstein J. Org. Chem. 2012, 8, 1318–1332, doi:10.3762/bjoc.8.151

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  • ICs are formed with block copolymers or with two or more different homopolymers, the resulting coalesced samples can exhibit intimate mixing between the copolymer blocks, or between entire homopolymer chains. Each of the distinct behaviors observed for polymers coalesced from their ICs is a
  • -nucleated PET not only possesses improved properties, but contains no incompatible additives, and so may be readily recycled. Coalesced block copolymers The triblock copolymer PCL-PPG-PCL, with noncrystallizable central poly(propylene oxide blocks), was synthesized by coordinated ring-opening polymerization
  • preferentially degraded by the enzyme. Regulation of their biodegradation behavior, through formation of and coalescence from CD ICs, may enhance the use of block copolymers in drug delivery and controlled release systems, because of its decisive importance in these applications. Coalesced polymer blends
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Published 16 Aug 2012

Conjugated polymers containing diketopyrrolopyrrole units in the main chain

  • Bernd Tieke,
  • A. Raman Rabindranath,
  • Kai Zhang and
  • Yu Zhu

Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92

Graphical Abstract
  • presented. DPP-based polymers The first DPP-based polymer was described by Yu et al. in 1993 [13]. Conjugated block copolymers containing phenylene, thienylene and N-alkyl substituted diphenyl DPP units in the main chain were synthesized by Stille coupling. Photorefractive polymers were prepared containing
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Published 31 Aug 2010

Novel multi-responsive P2VP-block-PNIPAAm block copolymers via nitroxide-mediated radical polymerization

  • Cathrin Corten,
  • Katja Kretschmer and
  • Dirk Kuckling

Beilstein J. Org. Chem. 2010, 6, 756–765, doi:10.3762/bjoc.6.89

Graphical Abstract
  • block copolymers are able to form so called schizophrenic micelles in aqueous solution. Here, such polymers are prepared via nitroxide-mediated radical polymerization (NMRP). In a first step nitroxide-terminated poly(2-vinylpyridine) (P2VP) was prepared with different molecular weights and narrow
  • molecular weight distributions. The best reaction conditions, optimized by kinetic studies, were bulk polymerization at 110 °C. Using P2VP as a macroinitiator, the synthesis of new soluble linear block copolymers of P2VP and poly(N-isopropylacrylamide) (PNIPAAm) (P2VP-block-PNIPAAm) was possible. The
  • calorimetry (DSC). Block copolymers showed pH- and temperature-responsive solubility in aqueous media. By increasing the P2VP content, the phase transition temperature shifted to lower temperatures (e.g. 26 °C for P2VP114-block-PNIPAAm180). Depending on the resulting block length, temperature and pH value of
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Published 20 Aug 2010

Poly(glycolide) multi-arm star polymers: Improved solubility via limited arm length

  • Florian K. Wolf,
  • Anna M. Fischer and
  • Holger Frey

Beilstein J. Org. Chem. 2010, 6, No. 67, doi:10.3762/bjoc.6.67

Graphical Abstract
  • strategy it is possible to combine high molecular weight with good molecular weight control (up to 16,000 g/mol, PDI = 1.4–1.7), resulting in PGA multi-arm star block copolymers containing more than 90 wt % GA. The successful linkage of PGA arms and PG core via this core first/grafting from strategy was
  • environment when core–shell topologies for encapsulation are desired. Here we present a solvent-free synthetic strategy for multi-arm star block copolymers with a hyperbranched polyether core and PGA arms, systematically varying arm length. The combination of glycolide with a multifunctional initiator studied
  • penultimate unit at the same time). Hence H′ is predominantly observed for low glycolide fractions. This signal assignment is consistent with literature data for PGA-co-poly(ε-caprolactone) copolymers [36][37], as well as PLLA–PG star block copolymers which have recently been developed by our group [22]. The
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Published 21 Jun 2010

Synthesis and crossover reaction of TEMPO containing block copolymer via ROMP

  • Olubummo Adekunle,
  • Susanne Tanner and
  • Wolfgang H. Binder

Beilstein J. Org. Chem. 2010, 6, No. 59, doi:10.3762/bjoc.6.59

Graphical Abstract
  • polymerization in comparison to U1. The synthesis of block copolymers with molecular weights up to Mn = 31 000 g/mol with low polydispersities (Mw/Mn = 1.2) is reported. Keywords: block copolymer (BCP); crossover reaction; MALDI; NEOLYST™; ROMP; Introduction Block copolymers are macromolecules composed of
  • linear or non-linear arrangements of chemically different polymeric chains. If the different blocks are incompatible, a rich variety of well defined self-assembled structures both in bulk and selective solvents arises [1]. The synthetic approach to block copolymers has been widely discussed [1] and
  • achieved extensively via living polymerization methods. Thus, besides acyclic diene metathesis polymerization (ADMET) [2], ring opening metathesis polymerization (ROMP) [3][4][5] is another type of olefin metathesis polymerization that can be used for the synthesis of block copolymers. Early examples of
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Published 01 Jun 2010

New amphiphilic glycopolymers by click functionalization of random copolymers – application to the colloidal stabilisation of polymer nanoparticles and their interaction with concanavalin A lectin

  • Otman Otman,
  • Paul Boullanger,
  • Eric Drockenmuller and
  • Thierry Hamaide

Beilstein J. Org. Chem. 2010, 6, No. 58, doi:10.3762/bjoc.6.58

Graphical Abstract
  • stability and the biological points of view. In such block copolymers, the hydrophobic part is enhanced in comparison to molecular surfactants, which allows a better adsorption (by reducing the exchange dynamics) and increases the long term stability. This stronger adsorption also reduces the residual
  • nanoparticles, thus increasing their circulation in the body. The polyether triblock copolymer PEO-b-PPO-b-PEO Pluronic® F-68 (PF-68) is approved by the US Food and Drug Administration and is thus widely used in pharmaceutical formulations. Glycopolymers can advantageously replace these block copolymers. In
  • surfactants for mini-emulsion polymerization [5][6]. Amphiphilic block copolymers with pendant glucosamine units have been obtained by living cationic polymerization and their interaction with wheat germ agglutinin lectin investigated [7]. More recently, the synthesis of neoglycopolymers by living radical
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Published 01 Jun 2010

Ring opening metathesis polymerization-derived block copolymers bearing chelating ligands: synthesis, metal immobilization and use in hydroformylation under micellar conditions

  • Gajanan M. Pawar,
  • Jochen Weckesser,
  • Siegfried Blechert and
  • Michael R. Buchmeiser

Beilstein J. Org. Chem. 2010, 6, No. 28, doi:10.3762/bjoc.6.28

Graphical Abstract
  • micellar catalytic set up are discussed. Keywords: block copolymers; catalysis; hydrophilic polymers; metathesis; micelles; Introduction Catalysts bound to amphiphilic block copolymers find increasing use in micellar catalysis since they combine the advantages of both homogeneous and heterogeneous
  • was converted into M2 via quaternization of the tertiary amine with methyl iodide. Synthesis of homo- and block copolymers via ROMP [12][13] ROMP has already been used for the synthesis of micelle-forming block copolymers [14], however, the one used in this study, i.e. poly(M1-b-M2), required special
  • catalysts covalently bound to amphiphilic polymers are used [2][4][29][30][31][32][33], have been reported to present suitable catalysts for numerous catalytic reactions. The hydroformylation under micellar conditions using catalysts bound to amphiphilic block copolymers was first reported by Nuyken et al
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Published 23 Mar 2010
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